Airworthiness Directives; Thrush Aircraft, Inc. Model 600 S2D and S2R Series Airplanes, 3127-3141 [2010-594]
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Federal Register / Vol. 75, No. 12 / Wednesday, January 20, 2010 / Rules and Regulations
TABLE 1—STRUCTURAL REPAIR MANUALS ACCEPTABLE BEFORE THE EFFECTIVE DATE OF THIS AD
Document
Airbus
Airbus
Airbus
Airbus
A330 Structural Repair Manual ................................................................................................................
A330 Structural Repair Manual ................................................................................................................
A340–200/–300 Structural Repair Manual ...............................................................................................
A340–200/–300 Structural Repair Manual ...............................................................................................
(4) As of the effective date of this AD, no
person may replace a movable flap track
fairing No. 3 on that airplane, unless the
replacement fairing has been modified or
repaired in accordance with the requirements
of this AD.
FAA AD Differences
Note 1: This AD differs from the MCAI
and/or service information as follows: The
MCAI prohibits replacement of the affected
part after modification, but this AD prohibits
replacing the affected part as of the effective
date of this AD.
Other FAA AD Provisions
(g) The following provisions also apply to
this AD:
(1) Alternative Methods of Compliance
(AMOCs): The Manager, International
Branch, ANM–116, FAA, has the authority to
approve AMOCs for this AD, if requested
using the procedures found in 14 CFR 39.19.
Send information to ATTN: Vladimir
Ulyanov, Aerospace Engineer, International
Branch, ANM–116, Transport Airplane
Directorate, FAA, 1601 Lind Avenue, SW.,
Renton, Washington 98057–3356; telephone
(425) 227–1138; fax (425) 227–1320. Before
using any approved AMOC on any airplane
to which the AMOC applies, notify your
principal maintenance inspector (PMI) or
principal avionics inspector (PAI), as
appropriate, or lacking a principal inspector,
your local Flight Standards District Office.
(2) Airworthy Product: For any requirement
in this AD to obtain corrective actions from
a manufacturer or other source, use these
actions if they are FAA-approved. Corrective
actions are considered FAA-approved if they
are approved by the State of Design Authority
(or their delegated agent). You are required
to assure the product is airworthy before it
is returned to service.
(3) Reporting Requirements: For any
reporting requirement in this AD, under the
provisions of the Paperwork Reduction Act,
the Office of Management and Budget (OMB)
has approved the information collection
requirements and has assigned OMB Control
Number 2120–0056.
pwalker on DSK8KYBLC1PROD with RULES
Revision
Bulletin A340–57–4103, Revision 01, dated
April 3, 2008; as applicable; to do the actions
required by this AD, unless the AD specifies
otherwise.
(1) The Director of the Federal Register
approved the incorporation by reference of
this service information under 5 U.S.C.
552(a) and 1 CFR part 51.
(2) For service information identified in
this AD, contact Airbus SAS—Airworthiness
Office—EAL, 1 Rond Point Maurice Bellonte,
31707 Blagnac Cedex, France; fax +33 5 61
93 45 80, e-mail airworthiness.A330–
A340@airbus.com; Internet https://
www.airbus.com.
(3) You may review copies of the service
information at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton,
Washington. For information on the
availability of this material at the FAA, call
425–227–1221 or 425–227–1152.
(4) You may also review copies of the
service information that is incorporated by
reference at the National Archives and
Records Administration (NARA). For
information on the availability of this
material at NARA, call 202–741–6030, or go
to: https://www.archives.gov/federal_register/
code_of_federal_regulations/
ibr_locations.html.
Issued in Renton, Washington, on
December 16, 2009.
Stephen P. Boyd,
Acting Manager,
Transport Airplane Directorate, Aircraft
Certification Service.
[FR Doc. 2010–487 Filed 1–19–10; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2007–27862; Directorate
Identifier 2007–CE–036–AD; Amendment
39–16150; AD 2009–26–11]
RIN 2120–AA64
Related Information
(h) Refer to MCAI European Aviation
Safety Agency Airworthiness Directive 2008–
0153, dated August 8, 2008; and Airbus
Mandatory Service BulletinsA330–57–3095,
Revision 02, and A340–57–4103, Revision
01, both dated April 3, 2008; for related
information.
AGENCY: Federal Aviation
Administration (FAA), DOT.
ACTION: Final rule.
Material Incorporated by Reference
(i) You must use Airbus Mandatory Service
Bulletin A330–57–3095, Revision 02, dated
April 3, 2008; or Airbus Mandatory Service
SUMMARY: We are adopting a new
airworthiness directive (AD) to
supersede AD (AD) 2006–07–15, which
applies to Thrush Aircraft, Inc. Model
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Airworthiness Directives; Thrush
Aircraft, Inc. Model 600 S2D and S2R
Series Airplanes
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Date
October
January
October
January
1,
1,
1,
1,
2008.
2009.
2008.
2009.
600 S2D and S2R (S–2R) series airplanes
(type certificate previously held by
Quality Aerospace, Inc. and Ayres
Corporation). AD 2006–07–15 currently
requires repetitive inspections of the
1/4-inch and 5/16-inch bolt hole areas
on the wing front lower spar caps for
fatigue cracking; replacement or repair
of any wing front lower spar cap where
fatigue cracks are found; and reporting
of any fatigue cracks found to the FAA.
AD 2006–07–15 also puts the affected
airplanes into groups for compliance
time and applicability purposes. Since
we issued AD 2006–07–15, FAA
analysis reveals that inspections are not
detecting all existing cracks and shows
the incidences of undetected cracks will
increase as the airplanes age.
Consequently, this AD retains the
actions of AD 2006–07–15 and imposes
a life limit on the wing front lower spar
caps that requires replacement of the
wing front lower spar caps when the life
limit is reached. This AD also changes
the requirements and applicability of
the groups discussed above and removes
the ultrasonic inspection method. We
are issuing this AD to prevent wing
front lower spar cap failure caused by
undetected fatigue cracks. Such failure
could result in loss of a wing in flight.
DATES: This AD becomes effective on
February 24, 2010.
On February 24, 2010, the Director of
the Federal Register approved the
incorporation by reference of Thrush
Aircraft, Inc. Custom Kit No. CK–AG–
41, Revision A, dated March 8, 2007,
listed in this AD.
As of May 20, 2003 (68 FR 15653), the
Director of the Federal Register
approved the incorporation by reference
of Quality Aerospace, Inc. Custom Kit
No. CK–AG–30, dated December 6,
2001, listed in this AD.
As of July 25, 2000 (65 FR 36055), the
Director of the Federal Register
approved the incorporation by reference
of Ayres Corporation Service Bulletin
No. SB–AG–39, dated September 17,
1996; and Ayres Corporation Custom Kit
No. CK–AG–29, dated December 23,
1997, listed in this AD.
ADDRESSES: To get the service
information identified in this AD,
contact Thrush Aircraft, Inc., 300 Old
Pretoria Road, P.O. Box 3149, Albany,
Georgia 31706–3149. The service
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information is also available on the
Internet at https://
www.thrushaircraft.com.
To view the AD docket, go to U.S.
Department of Transportation, Docket
Operations, M–30, West Building
Ground Floor, Room W12–140, 1200
New Jersey Avenue, SE., Washington,
DC 20590, or on the Internet at https://
www.regulations.gov. The docket
number is FAA–2007–27862;
Directorate Identifier 2007–CE–036–AD.
FOR FURTHER INFORMATION CONTACT:
—Cindy Lorenzen, Aerospace Engineer,
ACE–115A, Atlanta Aircraft
Certification Office, 1701 Columbia
Avenue, College Park, Georgia 30337;
telephone: (404) 474–5524; facsimile:
(404) 474–5606; e-mail:
cindy.lorenzen@faa.gov; or
—William O. Herderich, Aerospace
Engineer, ACE–117A, Atlanta Aircraft
Certification Office, 1701 Columbia
Avenue, College Park, Georgia 30337;
telephone: (404) 474–5547; facsimile:
(404) 474–5606; e-mail:
william.o.herderich@faa.gov.
SUPPLEMENTARY INFORMATION:
pwalker on DSK8KYBLC1PROD with RULES
Discussion
On April 27, 2009, we issued a
proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to
include an AD that would apply to
certain Thrush Aircraft, Inc. Model 600
S2D and S2R (S–2R) series airplanes
(type certificate previously held by
Quality Aerospace, Inc. and Ayres
Corporation). This proposal was
published in the Federal Register as a
notice of proposed rulemaking (NPRM)
on May 4, 2009 (74 FR 20431). The
NPRM proposed to supersede AD 2006–
07–15, Amendment 39–14542 (71 FR
19788, April 17, 2006) with a new AD
that would:
• Retain the actions of AD 2006–07–
15;
• Add life limits for the wing front
lower spar caps;
• Lower the initial and repetitive
inspection times for Group 5 airplanes;
• Correct some airplane Group
classifications;
• Add an airplane to the
Applicability section; and
• Remove the use of ultrasonic
inspection methods.
For replacement of the wing front
lower spar caps, the initial compliance
time for all airplanes will be at least an
additional 500 hours time-in-service
(TIS) after the effective date of this AD.
Calculated from actual flight hour data
from 285 S2R series airplanes, 500
hours TIS equates to the average yearly
operational time. The compliance
schedules should give owner/operators
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enough time to schedule the
replacement of the wing front lower
spar caps.
Although not required in this AD, we
recommend installing ‘‘big butterfly’’
and lower splice plates, P/N 20211–09
and P/N 20211–11, or Thrush Aircraft,
Inc. Custom Kit No. CK–AG–41,
Revision A, since they increase the
strength of the wing beyond the
minimum safety standards.
compliance times result in an average
operator having at least one year to
comply with the AD; however, most
operators will have much longer than
one year to replace the wing front lower
spar caps. These graduated compliance
times should allow enough time for
adequate supply of parts and repair
facility availability.
We are not changing the final rule AD
action based on this comment.
Comments
We provided the public the
opportunity to participate in developing
this AD. The following presents the
comments received on the proposal and
FAA’s response to each comment:
Comment Issue No. 2: Withdraw the AD
Charles Brumley states that the pilot
should be allowed to make his own
decision whether a new spar cap is
needed and requests an alternative to
this AD.
Mr. Brumley further states that he
believes the AD is unnecessary for the
following reasons:
• If the pilot is involved in the
maintenance of the airplane, then the
pilot can make an informed decision
about whether or not to install a new
spar cap and whether or not the aircraft
is in a condition for safe operation;
• The AD will cause undue economic
hardship on the airplane operators and
the farms that use aerial application
services;
• There have only been a few cracks
found, i.e., that there is not enough
service history to support issuance of an
AD; and
• The large butterfly plates are
adequate to ensure safety of the pilot
until a spar cap crack is found.
We infer this as a request for the FAA
to withdraw the AD.
We do not agree with the commenter.
While the commenter may have
maintained his airplane adequately, the
formation of fatigue cracks mainly
relates to the airplane’s design and
operation. Replacement of the wing
front lower spar caps when they have
reached their life limits is currently the
only means known to the FAA to
address the unsafe condition.
We have extensive crack data that
currently shows 176 wings on 123
airplanes had cracks in the wing front
lower spar caps. As the incidences of
cracking increase, which has occurred
in the Thrush airplanes, the chance of
an existing crack not being detected
during an inspection increases.
Airplanes with cracks in the wing front
lower spar caps are unable to meet
ultimate strength requirements, which
could lead to a wing failure. The only
known way of mitigating this risk is to
replace the wing front lower spar caps.
There are already procedures in place
for owner/operators to request an
alternative to any AD. Use the
alternative method of compliance
(AMOC) procedures provided in this AD
Comment Issue No. 1: Extend
Compliance Time To Replace the Spar
Caps
Marc Fries states that a large portion
of the affected airplanes will need to
address a spar replacement within a
very short period of time, overwhelming
a limited number of repair facilities. Mr.
Fries also states that most operators
have a short ‘‘down time’’ during their
season in which to do this type of
repair, and many operators will run out
of flying hours before a repair facility
can do the work or even get the kits
from the factory.
Mr. Fries requests an extension of the
compliance time because there are a
limited number of repair facilities, and
the replacement parts may not be
available immediately. Mr. Fries also
requests to insert into the AD an
allowance for an extension of the
compliance time while continuing the
spar cap inspections.
We do not agree with the commenter.
As stated in the NPRM, allowance for
the compliance time based on the
limited number of repair facilities and
the limited availability of replacement
parts has already been made. For
airplanes that have already exceeded the
life limit replacement time for the wing
front lower spar caps, the minimum
compliance time for those with the
highest hours TIS, which are the
airplanes with the highest risk of spar
cap failure, is 500 hours TIS. Five
hundred hours TIS equates to an
average year of operation for these
airplanes. Airplanes that have exceeded
the life limit replacement time, but are
not at the highest level of risk, will be
allowed an even longer compliance time
of 1,000 hours TIS, 1,500 hours TIS, or
2,000 hours TIS based on the current
number of hours TIS on the wing front
lower spar caps. Airplanes that have not
yet reached the life limit replacement
time are allowed a minimum of 2,000
hours TIS to comply with the AD. These
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to request an AMOC. The request for an
AMOC must include any substantiating
information, such as stress and fatigue
data. The AMOC will be approved if we
find it provides an acceptable level of
safety.
We are not changing the final rule AD
action based on this comment.
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Comment Issue No. 3: Adjusted Life
Limits Based on Environmental
Conditions
Avenger Aircraft and Services
(Avenger) states the life limits for the
wing front lower spar caps should be
adjusted if environmental conditions
were not taken into account when
determining the life limits. The
commenter states that metal fatigue is
influenced by environmental
conditions.
We do not agree with the commenter’s
request to adjust the life limits. We did
take environmental conditions into
consideration during our analysis for
determining the life limits. The riskbased analysis used by the FAA used
actual reported crack data from inservice airplanes. These in-service data
came from airplanes operated in a
variety of environments; therefore, the
raw data used in the FAA’s analysis
include the effects caused by
environmental conditions.
We are not changing the final rule AD
action based on this comment.
Comment Issue No. 4: Adjust Life
Limits Based on Crack Sizes
Avenger states that the life limit of the
wing front lower spar cap could be
much shorter if crack sizes are taken
into account during the risk assessment.
Avenger also states that this can be
particularly significant when some fleet
crack sizes may have exceeded the
critical size without failing due to the
airplane not exceeding limit load at that
particular time.
We do not agree with the commenter’s
request. Although we did not include
the crack size in our analysis, we did
use a statistical approach and took into
account the TIS on the wing front lower
spar cap when the crack was found and
reported to the FAA. There are other
factors in place in the AD to mitigate the
risk associated with not using crack size
to determine the life limit of the wing
front lower spar caps. We determined a
life limit for continued operational
safety of the S2R fleet and did not
propose a life limit as defined in FAA
guidance for type certification of newly
certificated airplanes. Our analysis of
the crack data, which includes
allowances for both the statistically
significant amount of crack data on the
Thrush fleet and the existence of an
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inspection program for the wing front
lower spar caps, yielded the life limits
times for the wing front lower spar caps
shown in the NPRM.
We are not changing the final rule AD
action based on this comment.
Comment Issue No. 5: Remove Magnetic
Particle Inspection Method
Avenger states that the flaw size that
can be detected by the magnetic particle
inspection method is 0.69 inches, which
is in excess of the flaw size that would
allow the wing front lower spar cap to
continue to carry limit load.
Avenger states, therefore, magnetic
particle inspections should not be
utilized as a valid inspection method
and should be removed from the AD.
We do not agree with the commenter.
The magnetic particle inspection
interval was originally set at 500 hours
TIS by AD 2000–11–16 and was based
on crack growth analysis provided by
Ayres Corporation (Ayres). We accepted
Ayres’ proposed usage of U.S. Air Force
data from Report AFWAL 3–5–852,
which showed a reliably detectable
crack size (90 percent probability/95
percent confidence) of 0.12 inch when
using magnetic particle inspection
methods. Using this detectable crack
size with a repetitive inspection of 500
hours TIS allowed for at least two
inspections to occur after crack
initiation and prior to a crack reaching
its critical size. As the fleet aged and as
more cracks occurred in-service, the risk
to the fleet increased. To help mitigate
this risk, we doubled the frequency of
the inspections required in AD 2006–
07–15. In this AD we are requiring
inspections every 250 hours TIS, which
allows for four chances of detecting a
crack based on the data originally used
by Ayres. This same 250-hour TIS
inspection interval, along with imposing
a wing front lower spar cap life limit to
further mitigate risk, was included in
the proposed AD. The detectable crack
size of 0.12 inch used by Ayres is very
near the values of detectable size
currently suggested for use by the FAA
(Ref. Website sponsored by the FAA in
conjunction with Iowa State University
https://www.cnde.iastate.edu/faa-casr/
engineers/) of 0.13 to 0.15
inch. With the added conservatism of
four inspections to detect cracks before
reaching a critical crack size, when two
inspections are what is normally
required in a more ideal environment,
the inspection interval in this AD is
well within the current guidelines.
We are not changing the final rule AD
action based on this comment.
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Comment Issue No. 6: Require
Calibration Standards and Level 2 NDT
Personnel To Perform Eddy Current
Inspections
Avenger states that calibration
standards and Level 2 Non-destructive
Testing (NDT) personnel are necessary
to achieve reliability and repeatability
in the inspections. These calibration
standards are designed to replicate the
structure being inspected with
simulated flaws and are used every time
as a setup tool by the inspector prior to
conducting the on-aircraft inspection.
Utilization of these standards is the
current practice by all major aircraft
manufacturers and should be required
for the Thrush inspections in order to
ensure a 90 percent probability of
detection. In addition, the inspectors
should be fully certified Level 2 NDT
personnel with bolt hole eddy current
qualifications.
We do not agree with the commenter’s
request that a change is needed to the
AD. This AD and the ADs that this AD
supersedes allow for eddy current
inspection procedures to be approved
only through the FAA’s Aircraft
Certification Office (ACO). The FAA
ACO already requires each procedure to
have the correct type of calibration
standard as this is a basic requirement
for ensuring a good inspection. The
FAA ACO has not and will not approve
an eddy current inspection procedure
that does not include a requirement to
use only Level 2, or even more qualified
Level 3, certified NDT inspectors for
these eddy current inspections.
We are not changing the final rule AD
action based on this comment.
Comment Issue No. 7: Allow Installing
Supplemental Type Certificate (STC)
SA03654AT as a Terminating Action in
This AD
Avenger states that a solution that was
not available at the time the proposed
AD was written is now currently on the
market. Avenger requests that the
following information be included in
the AD. This solution is the Avenger
STC SA03654AT Avenger Extended
Performance Front Spar Enhancement
Kit.
STC SA03654AT installs FAAapproved replacement wing front lower
spar caps for all airplanes that are the
subject of this AD, except for Model S2D
airplanes. The replacement spars have a
life limit of 40,000 hours TIS with a
parts cost of $40,000 and an installation
cost of $25,500.
Avenger’s FAA STC replacement kit
includes the following:
• 2 lower wing front lower spar caps
(made from stainless steel, not 4000
series steel);
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• 2 front spar web doublers;
• 1 large butterfly plate (redesigned);
• 2 larger splice blocks (redesigned);
and
• All associated hardware for
installation.
Avenger requests that the AD be
amended to include the installation of
the Avenger Extended Performance
(AXP) kit as a terminating action to this
AD.
We agree with the commenter. The
replacement wing front lower spar caps
and other modification parts that are
approved by STC SA03654AT,
Installation of Avenger Extended
Performance Front Spar Enhancement
Kit (new wing front spar lower caps,
center splice and doublers), in
accordance with Part II of Avenger
Master Data List AAS–MDL–08–001,
Revision B, dated November 26, 2008,
or later FAA-approved revision, are a
viable terminating action to this AD.
The installation of STC SA03654AT is
an alternative to replacing the wing
front lower spar caps with Ayres/
Thrush wing front lower spar caps.
We will change the final rule AD
action to allow installing STC
SA03654AT as a terminating action for
this AD.
Comment Issue No. 8: Require Reaming
Bolt Hole Before Cold Working
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Avenger states it is their opinion that
the cold working process accomplished
as part of the Ayres Corporation Service
Bulletin No. SB–AG–39, dated
September 17, 1996, is not being
conducted correctly, and fatigue damage
is being introduced and made more
critical than if cold working was not
accomplished at all. In order to utilize
mandrel expansion in a safe manner, the
hole in question must first be reamed to
remove any corrosion or existing cracks
that are too small to be detected. This
‘‘insurance cut’’ is required to remove
any anomaly in the hole that may cause
an issue during the cold working
process.
Avenger requests the AD be amended
to explicitly state that prior to mandrel
expansion, an insurance ream, capable
of cleaning up a .03 inch undetected
crack followed by a bolt hole eddy
current inspection using a calibration
standard, be accomplished prior to the
mandrel expansion process.
We do not agree with the commenter.
The AD already requires using the cold
working procedure found in Ayres
Service Bulletin SB–AG–39, dated
September 17, 1996. Steps 7 and 8 in
the Rework section of this service
bulletin require the bolt holes to be
reamed before cold working of the
holes. These procedures must be
accomplished in order to be in
compliance with this AD.
We are not changing the final rule AD
based on this comment.
Comment Issue No. 9: Require
Installing Big Butterfly Plates
Michael Morris and Mr. Brumley state
that instead of mandating the
replacement of the wing lower spar
caps, they would like the FAA to
require installing big butterfly plates. In
addition to installing the big butterfly
plates, Mr. Morris also requests to keep
the current inspection intervals for
magnetic particle and eddy current
inspections, and add a visual inspection
every 100 hours TIS.
Mr. Morris states that he believes
replacing the spar cap is unnecessary for
the following reasons:
• The inspection program will
continue to work;
• The economic impact is too great;
and
• Some operators do not fly as
aggressively as others and should not be
penalized for the actions of the other
pilots.
We do not agree with the commenters.
The ‘‘big butterfly’’ plate does not have
enough strength to carry all of the
possible flight loads in the event the
wing spar cap is severed. This plate
cannot be solely relied upon to ensure
the safety of the airplane.
Even if the spar cap is not completely
severed but has a crack that is large
enough to see when performing the
commenter’s proposed 100-hour TIS
visual inspection, the remaining
strength in the wing spar joint is not
enough to carry all of the possible flight
loads. As explained in the proposed AD,
inspection reliability for any type of
inspection method is not 100 percent;
therefore, over time the probability of an
inspection failing to detect a crack
increases and something more needs to
be done to ensure the safety of the
airplanes.
As shown in the Initial Regulatory
Flexibility Analysis section of the
proposed AD, the economic impact was
extensively studied. While we agree the
AD will have a significant economic
impact on small businesses, the only
known way to ensure the safety of the
airplane is to replace the wing front
lower spar caps.
We also agree that there are many
variables affecting the life limit of the
wing front lower spar caps, including
the operating weights and operating G
loads. Higher weights and higher G
loads reduce the life limit of the wing
front lower spar caps. The only way to
consider giving credit to those who
operate at lower weights and lower G
loads would be if each individual
airplane had recorded data for every
flight since the wings were installed
showing the weights and G loads. Each
individual airplane owner would then
need to have fatigue analysis and tests
done by a qualified engineer to
determine the life limit for that
particular set of wings based on that
recorded data. The expense of
conducting this type of study for each
airplane may be higher than the cost of
replacement wing front lower spar caps;
therefore, it may not be an economically
viable alternative.
We are not changing the final rule AD
action based on this comment.
Conclusion
We have carefully reviewed the
available data and determined that air
safety and the public interest require
adopting the AD as proposed except for
the changes previously discussed and
minor editorial corrections. We have
determined that these minor
corrections:
• Are consistent with the intent that
was proposed in the NPRM for
correcting the unsafe condition; and
• Do not add any additional burden
upon the public than was already
proposed in the NPRM.
Costs of Compliance
We estimate that this AD will affect
808 airplanes in the U.S. registry,
including those airplanes affected by
AD 2006–07–15.
We estimate the following costs to do
each inspection:
Labor cost
Parts cost
Total cost per
airplane
Total cost on
U.S. operators
3 work-hours × $80 = $240 .........................................................................................................
$525
$765
$618,120
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We estimate the following costs to do
cold work of bolt holes for the repair
that may be required based on the
results of the inspection. We have no
way of determining the number of
airplanes that may need such repair:
Labor cost
Parts cost
Total cost per
airplane
1 work-hour × $80 = $80 .................................................................................................................................
$100
$180
We estimate the following costs to do
any reaming of outer holes to 5/16-inch
diameter for the repair that may be
required based on the results of the
inspection. We have no way of
determining the number of airplanes
that may need such repair:
Labor cost
Parts cost
Total cost per
airplane
1 work-hour × $80 = $80 ....................................................................................................................................
None ...............
$80
We estimate the following costs to do
any drilling and reaming of outer holes
and adding three holes to install a
Kaplan splice block for the repair that
may be required based on the results of
the inspection. We have no way of
determining the number of airplanes
that may need such modification:
Labor cost
Parts cost
Total cost per
airplane
65 work-hours × $80 = $5,200 ...................................................
$4,400 for splice block and $600 for hardware .........................
$10,200
We estimate the following costs to do
any necessary wing front lower spar cap
replacement with the optional Ayres or
Thrush part numbers (P/Ns) 20207–1,
20207–2, 20207–11, 20207–12, 20207–
13, 20207–14, 20207–15, or 20207–16
that will be required based on the
results of the inspection or by the wing
Labor cost per wing front lower spar cap
Parts cost per
wing front
lower spar cap
200 work-hours × $80 = $16,000 ...............................................
$8,000
However, the supply of individual
wing front lower spar caps (new or
used) is very limited.
We estimate the following costs to do
the optional installation of Thrush
front lower spar cap reaching the life
limit:
Total cost per airplane
Each spar cap replacement = $24,000
Two wing front lower spar caps per airplane = $48,000.
Aircraft, Inc. Custom Kit No. CK–AG–
41, Revision A, dated March 8, 2007.
This kit may be used to do any
necessary wing front lower spar cap
replacements that will be required based
on the results of the inspection or that
will be required based on reaching the
life limit:
Labor cost
Parts cost
Total cost per
airplane
300 work-hours × $80 = $24,000 ....................................................................................................................
$40,000
$64,000
We estimate the following costs to do
the optional installation of Avenger
Aircraft and Services STC SA03654AT
for Avenger Extended Performance
Front Spar Enhancement Kit. This kit
may be used to do any necessary wing
front lower spar cap replacements that
will be required based on the results of
the inspection or that will be required
based on reaching the life limit:
Parts cost
Total cost per
airplane
319 work-hours × $80 = $25,520 ....................................................................................................................
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Labor cost
$40,000
$65,500
The FAA estimates that 501 airplanes
affected by this AD will retire before
their wing front lower spar cap life
limits are reached.
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Authority for This Rulemaking
Title 49 of the United States Code
specifies the FAA’s authority to issue
rules on aviation safety. Subtitle I,
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Section 106 describes the authority of
the FAA Administrator. Subtitle VII,
Aviation Programs, describes in more
detail the scope of the agency’s
authority.
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We are issuing this rulemaking under
the authority described in Subtitle VII,
Part A, Subpart III, Section 44701,
‘‘General requirements.’’ Under that
section, Congress charges the FAA with
promoting safe flight of civil aircraft in
air commerce by prescribing regulations
for practices, methods, and procedures
the Administrator finds necessary for
safety in air commerce. This regulation
is within the scope of that authority
because it addresses an unsafe condition
that is likely to exist or develop on
products identified in this AD.
Final Regulatory Flexibility Analysis
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Introduction and Purpose of This
Analysis
The Regulatory Flexibility Act of 1980
(Pub. L. 96–354) (RFA) establishes ‘‘as a
principle of regulatory issuance that
agencies shall endeavor, consistent with
the objectives of the rule and of
applicable statutes, to fit regulatory and
informational requirements to the scale
of the businesses, organizations, and
governmental jurisdictions subject to
regulation.’’ To achieve this principle,
the RFA requires agencies to solicit and
consider flexible regulatory proposals
and to explain the rationale for their
actions to assure that such proposals are
seriously considered. The RFA covers a
wide-range of small entities, including
small businesses, not-for-profit
organizations, and small governmental
jurisdictions.
Agencies must perform a review to
determine whether a rule will have
significant economic impact on a
substantial number of small entities. If
the agency determines that it will, the
agency must prepare a regulatory
flexibility analysis as described in the
RFA.
We determined that this final rule
will have a significant economic impact
on a substantial number of small entities
and, accordingly, as required by section
603(a) of the RFA, we prepared and
published an initial regulatory
flexibility analysis (IRFA) as part of the
NPRM for this final rule (74 FR 20431,
May 4, 2009). Section 604 of the RFA
also requires an agency to publish a
final regulatory flexibility analysis
(FRFA) in the Federal Register when
issuing a final rule. Section 604(a)
requires that each FRFA contain:
• A succinct statement of the need
for, and objectives of, the final rule;
• A summary of the significant issues
raised by the public comments in
response to the IRFA, a summary of
agency’s assessment of such issues, and
a statement of any changes made to the
proposed final rule resulting from such
comments;
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• A description of the steps the
agency has taken to minimize the
significant economic impact on small
entities consistent with the stated
objectives of applicable statues,
including a statement of the factual,
policy, and legal reasons for selecting
the alternative adopted in the final rule
and why each one of the other
significant alternatives to the final rule
considered by the agency that affect the
impact on small entities was rejected.
• A description of and an estimate of
the number of small entities for which
the final rule will apply; and
• A description of the projected
reporting, recordkeeping, and other
compliance requirements of the final
rule, including an estimate of the classes
of small entities that will be subject to
the requirement and the type of
professional skills necessary for
preparation of the report or record.
Need for, and Objectives of Final Rule
A series of ADs, beginning in 1997
and culminating in AD 2006–07–15 in
2006, addressed the issue of fatigue
cracking of the wing front lower spar
caps in Thrush Aircraft, Inc. Model 600
S2D and S2R (S–2R) series airplanes
(type certificate previously held by
Quality Aerospace, Inc. and Ayres
Corporation). This type of fatigue
cracking, if not addressed, could result
in catastrophic wing failure. The
original 1997 AD was issued after an
accident on an S2R series airplane in
which the wing separated from the
airplane in flight. Requirements of
inspection and possible replacement
were changed in 2000 to repetitive
inspections and possible replacement.
In 2006, the inspection rate was doubled
after a completely severed wing front
lower spar cap was found on one of the
affected airplanes and the FAA noted
that it was working with Thrush
Aircraft, Inc. to develop a future
terminating action. Analysis indicated
that an undetected crack had existed
during the previous two repetitive
inspections of that wing front lower spar
cap.
Subsequent FAA analysis has shown
that wing front lower spar cap fatigue
cracking has increased as the fleet has
aged and will continue to increase.
Consequently, the incidences of
undetected cracks will increase,
increasing the probability of
catastrophic wing failure. The FAA has
concluded that repetitive inspections, as
required since the 2000 AD, are
insufficient by themselves to ensure the
safety of these airplanes and,
accordingly, in this final rule the FAA
is requiring wing front lower spar cap
life limits to address this safety issue.
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Summary of Significant Issues Raised by
the Public in Response to the IRFA,
Summary of FAA’s Assessment of Such
Issues, Statement of Changes Made to
the Final Rule as a Result of Such
Issues, Description of the Steps the
Agency Has Taken To Minimize a
Significant Economic Impact on Small
Entities, and Why Other Significant
Alternatives to the Final Rule That
Affect Small Entities Were Rejected
There were no public comments to
the IRFA, but there were public
comments to the proposed rule, which
have relevance for small and large
entities alike.
As noted in the preamble to the final
rule, Avenger commented that it has
developed a wing front lower spar
replacement kit, which was not
available when the proposed rule was
issued. The FAA has approved their kit
for a 40,000-hour TIS life limit. Avenger
requested that the FAA approve the
installation of its kit as a terminating
action to the AD. As noted in the
preamble, the FAA agrees with Avenger
that installation of its kit is a viable
terminating action to this AD.
Accordingly, it is an alternative to
replacing the wing front lower spar caps
with Ayres/Thrush spar caps; and the
FAA has incorporated this change in the
final rule. This is a significant issue
because the Ayres/Thrush kit, although
priced slightly lower than the Avenger
kit, has a lower life limit (ranging from
5,400 to 28,800 hours TIS.) Many of the
affected airplanes with the Ayres/
Thrush kit installed will require
multiple replacements over their
lifetimes and installation of the Ayres/
Thrush kit does not eliminate the
requirement of repetitive inspections
and reporting requirements.
Consequently, the estimated cost of the
final rule is lower given the availability
of the Avenger kit as a terminating
action. In the cost analysis for the
proposed rule, we estimated the total
cost to be $37.1 million. In the final
rule, we estimate total cost to be $20.1
million.1
As an alternative to replacing the
wing front lower spar caps, two
commenters suggested that the FAA
require installation of ‘‘big butterfly’’
plates. But, as the FAA noted in the
preamble, the ‘‘big butterfly plate’’ does
not have enough strength to carry all the
1 Individual replacement of the two original
equipment spars is cheaper (for one installation)
than installing the Ayres/Thrush kit or the Avenger
kit, but as noted in the ‘‘Cost of Compliance’’
section, the supply of these spar caps is very
limited. Accordingly, total cost is overestimated,
but only slightly, by our assumption that all
operators would comply by installing a kit (NPRM:
Ayres/Thrush kit, final rule: Avenger kit).
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Federal Register / Vol. 75, No. 12 / Wednesday, January 20, 2010 / Rules and Regulations
possible flight loads if the wing front
lower spar caps were severed.
Accordingly, this plate cannot be solely
relied upon to ensure the safety of the
airplane and is not an acceptable
alternative method of compliance to
replacing the wing front lower spar
caps.
Additionally, one commenter
suggested 100-hour TIS visual
inspections. As discussed in the
preamble, even if the wing front lower
spar cap is not completely severed, but
has a crack that is large enough to see
when performing the 100-hour TIS
visual inspection, the remaining
strength in the wing spar joint is not
enough to carry all possible flight loads.
Therefore, the 100-hour TIS visual
inspection alone is not a sufficient
alternative method of compliance.
The FAA believes there are currently
no other available alternative methods
of compliance to the final rule that will
allow the safety objectives of the final
rule to be achieved. The FAA, however,
has allowed a generous compliance
period that will significantly reduce the
economic impact on small and large
entities alike. As already noted in the
preamble, airplanes that have already
exceeded the life limit on their wing
front lower spar caps are allowed 500,
1,000, 1,500, or 2,000 hours TIS to
comply with the final rule, depending
on the current number of accumulated
hours TIS. Since the average usage rate
for the affected airplanes is about 500
hours TIS per year, these allowances are
equivalent, on average, to 1, 2, 3, and 4
years to comply with the final rule.
Airplanes that have not yet reached
their wing front lower spar cap life limit
are allowed a minimum of 2,000 hours
TIS or, on average, 4 years to comply
with the final rule.
For a complete summary of public
comments and the FAA’s responses,
please see the Comments section in the
preamble above.
This final rule will affect 808 U.S.registered and -operated Thrush
Aircraft, Inc. Model 600S2D and S2R
(S–2R) series airplanes. 2 In conducting
this analysis, the FAA reviewed data
from the FAA Registry to ascertain how
many Thrush Aircraft, Inc. were
registered and operated by small
entities. The FAA Registry indicates that
these 808 airplanes are owned by 546
separate entities in agricultural aviation.
All but one of these entities are small
entities as defined by the Small
Business Administration (SBA).
Although the FAA Registry does not
record financial or business data about
the registered owners of aircraft, and
such data for these entities are not
readily available elsewhere, it appears
that most, if not all, of the 546 entities
are engaged in crop dusting, spraying,
and seeding operations. These activities
are classified in North American
Industry Classification System (NAICS)
industry, NAICS 115112—Soil
Preparation, Planting, and Cultivating
(including Crop Dusting, Crop
Spraying). The concentration of these
entities in a single NAICS industry
reflects the specialized nature of
agricultural airplanes with restricted
airworthiness certificates. Furthermore,
several of these entities were classified
in the Standard Industrial Classification
(SIC) equivalent of NAICS 115112 by
https://www.manta.com. Although a few
of these entities may also be engaged in
firefighting, which is classified in
NAICS 115310—Support Activities for
Forestry (including Forest Fire
Suppression), the FAA is unable to
identify any of these entities as being
principally engaged in firefighting. The
SBA small business classification for
NAICS 115112 is a maximum of $6.5
million in business receipts, and for
NAICS 115310 it is a maximum of $16.5
million in business receipts. Only one
entity in this sample appears to have
business receipts over $6.5 million, and
no entity has business receipts in excess
of $16.5 million. Using the total number
of airplanes owned as a size criterion,
the FAA selected a sample of 41 of the
largest affected entities and found
median sales shown by https://
www.manta.com to be just $250,000
annually. Firms in agricultural aviation
appear to be inherently of small size.
Accordingly, the FAA estimates that 545
small entities will be affected by this
final rule.
2 FAA Registry, https://www.faa.gov/
licenses_certificates/aircraft_certification/
aircraft_registry/releasable_aircraft_download/.
Data downloaded on 4/14/08.
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A Description of and an Estimate of the
Number of Small Entities for Which the
Final Rule Will Apply
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3133
Reporting, Record Keeping, and Other
Compliance Requirements
Small entities will incur no new
reporting and record-keeping
requirements as a result of this final
rule. In fact, such requirements, for
small and large firms alike, will be
greatly reduced since installation of the
Avenger kit has been incorporated as an
alternative terminating action to this
final rule.
This final rule will affect U.S.
operators of Thrush Aircraft, Inc. Model
600S2D and S2R (S–2R) series
agricultural airplanes airplanes. The
affected airplanes were produced by
Thrush Aircraft, Inc. predecessor firms
over the period 1965–2000. This final
rule largely retains the requirements of
superseded AD 2006–07–15 to inspect/
repair/replace the currently installed
Ayres/Thrush wing front lower spar
caps. The new requirements set life
limits on the Ayres/Thrush wing front
lower spar caps and requires replacing
of these wing front lower spar caps
when the life limits are reached.
Economic Impact on Small Entities
Replacing the wing front lower spar
caps is expensive and, consequently, as
we show below, the final rule will have
a significant economic impact on the
substantial number of small firms we
identified above.
The total compliance cost
(undiscounted) is $65,520 for an
affected airplane for which the wing
front lower spar caps are replaced before
retirement, or zero for an affected
airplane that will retire before its
compliance date. Individual airplane
compliance costs will result in costs to
the small entities that own these
airplanes and will vary depending on
the number of affected airplanes owned
by the entity. The ownership table
below shows the variation in the
number of owners with particular
numbers of airplanes. The table shows
that almost 75 percent of the 546
individual owners have only one
affected airplane, and more than 90
percent of owners have no more than
two affected airplanes. The average
(mean) number of affected airplanes
held is 1.48, while the median number
held is just 1.00, so the median airplane
cost is equivalent to the median owner
cost.
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NUMBER OF THRUSH AIRCRAFT, INC. OWNERS HAVING PARTICULAR NUMBERS OF AFFECTED AIRPLANES
Number of
affected airplanes held by
single owner
Total .............................................................................................................................................
Mean ............................................................................................................................................
Median .........................................................................................................................................
Number of
owners
Cumulative
%
1
2
3
4
5
6
7
8
9
13
........................
1.48
1.00
406
86
26
13
7
2
2
1
2
1
546
........................
........................
74.4
90.1
94.9
97.3
98.5
98.9
99.3
99.5
99.8
100.0
........................
........................
........................
Source: FAA Registry. Data downloaded on 4/18/08.
In the ‘‘Cost of Compliance’’ section of
this final rule, we estimate total cost
(undiscounted) to be $20.1 million and
the present value cost to be $18.2
million. As noted above, the FAA
estimates that 545 of the 546 affected by
this final rule are small firms, and, in
fact, 99.7 percent of the final rule’s
estimated cost is attributed to small
entities. The following document
analyzes the impact of this cost on the
substantial number of small firms
identified above.
Because the FAA Registry does not
collect financial or business data on
these entities, and such data are not
readily available elsewhere, the FAA
also used Census Bureau size
distribution data to assess the economic
impact on small firms. The FAA used
data from the 2002 Census since this is
the latest census for which size
distribution by business receipts is
readily available. These data are
available in a special census
compilation for the SBA.3 The FAA
used the data for NAICS 115112—Soil
Preparation, Planting, and Cultivating
(including Crop Dusting, Crop
Spraying), but did not use the data for
NAICS 115310—Support Activities for
Forestry (including Forest Fire
Suppression) since, as noted above, a
very high percentage of the affected
small firms, if not all, meet the
classification standard of NAICS
115112. Moreover, the size distribution
of NAICS 115310 appears to be similar
to that of NAICS 115112. The
concentration of the affected airplanes
in one NAICS industry, noted above,
makes the use of census data feasible
and appropriate.
The relevant census data are provided
in the table below:
2002 CENSUS DATA FOR NAICS 115112—SOIL PREPARATION, PLANTING, AND CULTIVATING (INCL. CROP DUSTING,
CROP SPRAYING)—SMALL SIZE CLASSES
Measure
Total
Firms ........................................................
Percentage of firms ..................................
Upper bound percentile ...........................
Est. Receipts ($000) ................................
Receipts/Firm ($) .....................................
2336
........................
........................
$1,531,004
$655,396
$0–100
thousand
$100–500
thousand
509
21.8%
21.8%
$25,681
$50,454
992
42.5%
64.3%
$257,447
$259,523
$500
thousand–
1 million
412
17.6%
81.9%
$286,462
$695,296
$1–5 million
394
16.9%
98.8%
$772,401
$1,960,409
$5–10 million
29
1.2%
100.0%
$189,013
$6,517,690
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Source: ‘‘Firms’’ and ‘‘Est. Receipts’’ from Small Business Administration, Office of Advocacy. https://www.sba.gov/advo/research/us_rec02.txt.
The table above shows the number of
firms and business receipt data for the
five smallest size classes of NAICS
115112 that encompass the size range of
the firms affected by this final rule. In
the ‘‘Percentage of firms’’ row, for each
size class, the FAA calculates that
class’s number of firms as a percentage
of the total number of firms in the five
size classes. Cumulating this percentage
from the smallest to largest size class
establishes the ‘‘Upper bound
percentile’’—the cumulated percentage
of firms of business receipt size ranging
up to the upper bound of the size class.
The final rule’s cost for the firms at the
upper bound percentiles is then
estimated as the corresponding
percentiles in the estimated firm-level
compliance cost data. In order to assess
the economic impact of the final rule,
these costs are calculated as a
percentage of the census data upper
bounds.
For example, the upper bound
percentile for the $100–500 thousand
size class is 64.3 percent, so we estimate
the NAICS 115112 firms at that
percentile to have business receipts of
$500,000. As shown in the table below,
the FAA then determined the estimated
compliance cost of firms at the same
percentile in the compliance cost data to
be $57,584. The FAA assumes these
firms are the same, so the percentage
cost impact (AD Cost/Firm Size) is 11.5
percent. This procedure assumes the
size distribution of the 808 firms
affected by the final rule has a
3 Small Business Administration, Office of
Advocacy. https://www.sba.gov/advo/research/
us_rec02.txt.
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distribution similar to the overall
distribution of the small firms in NAICS
115112. It also assumes there is a perfect
rank correlation between the size of the
affected firms and the firms’ present
value compliance cost. While the latter
assumption is certainly not the case, any
deviation from such perfect correlation
can only increase the impact of the final
rule because smaller firms will have
3135
larger costs. Accordingly, the FAA’s
determination that the final rule will
have a significant impact on a
substantial number of small entities is
unaffected.
ECONOMIC IMPACT OF AD ON SMALL FIRMS
AD cost to firm
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The table above shows a zero-cost
impact on a firm at the 21.8 percentile.
This result reflects the estimate in the
FRFA cost analysis (see docket) that
more than 500 older airplanes will retire
before their wing front lower spar cap
life limits are reached. As already
mentioned, the AD cost for a firm at the
64.3 percentile is $61,754, which as a
percentage of estimated firm size (size
class upper bound) is 11.5 percent of
annual business receipts. This impact
declines to 6.3 percent for a firm at the
81.9 percentile and to 4.1 percent for a
firm at the 98.8 percentile. The overall
pattern is zero impact for the smallest of
the small firms owners of the oldest
airplanes, but a highly positive impact
for the medium-sized small firms. In
percentage terms, this impact falls for
the largest small firms, but remains at a
substantial level. While the FAA can
make no definitive inference on the
impact of the final rule on firms
between the 21.8 and 64.3 percentiles,
the FAA notes the cost varies from 6.3
percent up to 11.5 percent of annual
business receipts for 96 firms between
the 81.9 and 64.3 percentiles and from
4.1 percent to 6.3 percent of annual
business receipts for 92 firms between
the 98.8 and 81.9 percentiles. These
estimated percentage impacts are
substantial. Therefore, the FAA
concludes that this final rule will have
a significant impact on a substantial
number of small entities.
International Trade Impact Analysis
The Trade Agreement Act of 1979
prohibits Federal agencies from
establishing any standards or engaging
in related activities that create
unnecessary obstacles to the foreign
commerce of the United States. The
statute does not consider legitimate
domestic objectives, such as safety, as
unnecessary. The statute also requires
consideration of international standards
and, where appropriate, that they be the
15:59 Jan 19, 2010
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21.8
64.3
81.9
98.8
percentile
percentile
percentile
percentile
Unfunded Mandates Reform Act
Assessment
Title II of the Unfunded Mandates
Reform Act of 1995 (Pub. L. 104–4)
requires each Federal agency to prepare
a written statement assessing the effects
of any Federal mandate in a proposed or
final agency rule that may result in an
expenditure of $100 million or more
(adjusted annually for inflation with the
base year 1995) in any one year by State,
local, and Tribal governments in the
aggregate, or by the private sector. The
Act deems such a mandate to be a
‘‘significant regulatory action.’’ The FAA
currently uses an inflation-adjusted
value of $136.1 million. This rule does
not contain such a mandate.
Regulatory Findings
We have determined that this AD will
not have federalism implications under
Executive Order 13132. This AD will
not have a substantial direct effect on
the States, on the relationship between
the national government and the States,
or on the distribution of power and
responsibilities among the various
levels of government.
For the reasons discussed above, I
certify that this AD:
1. Is not a ‘‘significant regulatory
action’’ under Executive Order 12866;
2. Is not a ‘‘significant rule’’ under the
DOT Regulatory Policies and Procedures
(44 FR 11034, February 26, 1979); and
3. Will have a significant economic
impact, positive or negative, on a
substantial number of small entities
under the criteria of the Regulatory
Flexibility Act.
Frm 00011
Cumulative
number of
firms
0.0%
11.5%
6.3%
4.1%
119.2
351.5
447.9
540.2
....................................................
....................................................
....................................................
....................................................
basis for U.S. standards. The FAA is
issuing this final rule because of a
known safety problem. Therefore, this
final rule AD action applies only to U.S.
registered airplanes and is not
considered an unnecessary obstacle to
international trade.
PO 00000
AD cost/firm
size
$100,000
$500,000
$1,000,000
$5,000,000
Firm percentile
$0 ........................................................................
$57,584 ...............................................................
$63,220 ...............................................................
$203,502 .............................................................
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Estimated firm
size (Census
Bureau’s
receipts upper
bound)
Fmt 4700
Sfmt 4700
We prepared a summary of the costs
to comply with this AD (and other
information as included in the
Regulatory Evaluation) and placed it in
the AD Docket. You may get a copy of
this summary by sending a request to us
at the address listed under ADDRESSES.
Include ‘‘Docket No. FAA–2007–27862;
Directorate Identifier 2007–CE–036–AD’’
in your request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation
safety, Incorporation by reference,
Safety.
Adoption of the Amendment
Accordingly, under the authority
delegated to me by the Administrator,
the Federal Aviation Administration
amends part 39 of the Federal Aviation
Regulations (14 CFR part 39) as follows:
■
PART 39—AIRWORTHINESS
DIRECTIVES
1. The authority citation for part 39
continues to read as follows:
■
Authority: 49 U.S.C. 106(g), 40113, 44701.
§ 39.13
[Amended]
2. The FAA amends § 39.13 by
removing Airworthiness Directive (AD)
2006–07–15, Amendment 39–14542 (71
FR 16691, April 4, 2006), and adding
the following new AD:
■
2009–26–11 Thrush Aircraft, Inc. (Type
Certificate Previously Held by Quality
Aerospace, Inc. and Ayres Corporation):
Amendment 39–16150; Docket No.
FAA–2007–27862; Directorate Identifier
2007–CE–036–AD.
Effective Date
(a) This AD becomes effective on February
24, 2010.
Affected ADs
(b) The following lists a history of the ADs
affected by this AD action:
(1) This AD supersedes AD 2006–07–15,
Amendment 39–14542;
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(2) AD 2006–07–15 superseded AD 2003–
07–01, Amendment 39–13097;
(3) AD 2003–07–01 superseded AD 2000–
11–16, Amendment 39–11764;
(4) AD 2000–11–16 superseded AD 97–17–
03, Amendment 39–10195; and
(5) AD 97–17–03 superseded AD 97–13–11,
Amendment 39–10071.
Applicability
(c) This AD affects the following airplane
models and serial numbers (S/Ns) in Table 1
that are certificated in any category when
wing front lower spar cap part numbers (P/
Ns) 20207–1, 20207–2, 20207–11, 20207–12,
20207–13, 20207–14, 20207–15, or 20207–16
are installed. This AD applies to the S/Ns in
Table 1 with or without a ‘‘DC’’ suffix. This
AD does not affect airplanes with any other
wing front lower spar cap part number, e.g.
Thrush P/N 22507 (any dash number) or
Supplemental Type Certificate (STC)
SA03654AT parts. The table also identifies
the group that each airplane belongs in when
determining inspection compliance times
and life limit times for the parts:
TABLE 1—APPLICABILITY AND AIRPLANE GROUPS
Model
(1)
(2)
(3)
(4)
(5)
S/Ns
S–2R .......................................................
S2R–G1 ..................................................
S2R–R1820 .............................................
S2R–T15 .................................................
S2R–T34 .................................................
(6) S2R–G10 ................................................
(7) S2R–G5 ..................................................
(8) S2R–G6 ..................................................
(9) S2RHG–T65 ............................................
(10) S2R–R1820 ...........................................
(11) S2R–T34 ...............................................
pwalker on DSK8KYBLC1PROD with RULES
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
(26)
S2R–T45 ...............................................
S2R–T65 ...............................................
600 S2D ................................................
S–2R .....................................................
S2R–R1340 ...........................................
S2R–R3S ..............................................
S2R–T11 ...............................................
S2R–G1 ................................................
S2R–G10 ..............................................
S2R–G6 ................................................
S2RHG–T34 ..........................................
S2R–T15 ...............................................
S2R–T34 ...............................................
S2R–T45 ...............................................
S–2R .....................................................
(d) The S/Ns of Model S2R–T15 airplanes
could incorporate T15-xxx and T27-xxx (xxx
is the variable for any of the S/Ns beginning
with T15- and T27-). This AD applies to both
of these S/N designations as they are both
Model S2R–T15 airplanes.
(e) The S/Ns of Model S2R–T34 airplanes
could incorporate T34-xxx, T36-xxx, T41xxx, or T42-xxx (xxx is the variable for any
of the S/Ns beginning with T34-, T36-,
T41-, and T42-). This AD applies to all of
these S/N designations as they are all Model
S2R–T34 airplanes.
(f) Any Group 3 airplane that has been
modified with a hopper of a capacity more
than 410 gallons, a piston engine greater than
600 horsepower, or a gas turbine engine
greater than 600 horsepower, is a Group 1
airplane for the purposes of this AD. Inspect
the airplane at the Group 1 compliance time
specified in this AD. Replace the wing front
lower spar caps in accordance with the
formulas given in paragraph (k) of this AD.
(g) Group 6 airplanes were originally
manufactured with higher horsepower radial
engines, but were converted to lower
horsepower radial engines. They are now
configured identically to Group 3 airplanes.
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Group
5000R through 5100R, except 5010R, 5031R, 5038R, 5047R, and 5085R .....................
G1–101 through G1–106 ....................................................................................................
R1820–001 through R1820–035 ........................................................................................
T15–001 through T15–033 (also see paragraph (d) of this AD) .......................................
6000R through 6049R, T34–001 through ..........................................................................
T34–143, T34–145, T34–171, T34-180, and .....................................................................
T34–181 (also see paragraph (e) of this AD) ....................................................................
G10–101 through G10–138, G10–140, and ......................................................................
G10–141 .............................................................................................................................
G5–101 through G5–105 ....................................................................................................
G6–101 through G6–147 ....................................................................................................
T65–002 through T65–018 .................................................................................................
R1820–036 .........................................................................................................................
T34–144, T34–146 through T34–170, T34–172 through T34–179, and T34–189
through T34–234 (also see paragraph (e) of this AD).
T45–001 through T45–014 .................................................................................................
T65–001 through T65–018 .................................................................................................
All serial numbers beginning with 600–1311D ...................................................................
1380R, 1416R through 2592R, 3000R, and 3002R ..........................................................
R1340–001 through R1340–035 ........................................................................................
R3S–001 through R3S–011 ...............................................................................................
T11–001 through T11–005 .................................................................................................
G1–107 through G1–115 ....................................................................................................
G10–139, G10–142 through G10–165 ...............................................................................
G6–148 through G6–155 ....................................................................................................
T34HG–102 ........................................................................................................................
T15–034 through T15–040 (also see paragraph (d) of this AD) .......................................
T34–236 through T34–270 (also see paragraph (e) of this AD) .......................................
T45–015 ..............................................................................................................................
5010R, 5031R, 5038R, 5047R, and 5085R .......................................................................
Unsafe Condition
(h) This AD is the result of the analysis of
data from 117 wing front lower spar cap
fatigue cracks found on similar design Model
600 S2D and S2R (S–2R) series airplanes and
the FAA’s determination that the
replacement of high time wing front lower
spar caps is necessary to address the unsafe
condition for certain airplanes. Since we
issued AD 2006–07–15, analysis reveals that
inspections are not detecting all existing
cracks, and incidences of undetected cracks
are increasing. This AD retains the actions of
AD 2006–07–15 and imposes a life limit on
the wing front lower spar caps that requires
you to replace the wing front lower spar caps
when the life limit is reached. This AD also
changes the requirements and applicability of
the groups discussed above and removes the
ultrasonic inspection method. We are issuing
this AD to prevent wing front lower spar cap
failure caused by undetected fatigue cracks.
Such failure could result in loss of a wing.
Compliance
(i) To address the problem, do the
following, unless already done:
(1) If you have already done an inspection
required by AD 2006–07–15, within the next
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1
1
1
1
2
2
2
2
2
2
2
2
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3
3
3
3
5
5
5
5
5
5
5
6
30 days after February 24, 2010 (the effective
date of this AD), identify the number of hours
time-in-service (TIS) since your last
inspection required by AD 2006–07–15. You
will need this to establish the inspection
interval for the next inspection required by
this AD.
(2) Inspect the two outboard bolt hole areas
(whether 1⁄4-inch and 5⁄16-inch diameter bolt
holes or both 5⁄16-inch diameter bolt holes) on
each wing front lower spar cap for fatigue
cracking using magnetic particle or eddy
current procedures. If Kaplan splice blocks,
P/N 22515–1/–3 or P/N 88–251, are installed
following Quality Aerospace, Inc. Custom Kit
No. CK–AG–30, dated December 6, 2001,
inspect the three outboard bolt hole areas on
each wing front lower spar cap for fatigue
cracking using magnetic particle or eddy
current procedures. Use the compliance
times listed in paragraph (i)(3) of this AD for
the initial inspection and the compliance
time listed in paragraphs (i)(5), (i)(6), or (i)(7)
of this AD for the repetitive inspections. The
cracks may emanate from the bolt hole on the
face of the wing front lower spar cap or they
may occur in the shaft of the hole. Inspect
both of those areas.
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(i) If using the magnetic particle method,
inspect using the ‘‘Inspection’’ portion of the
‘‘Accomplishment Instructions’’ and ‘‘Lower
Splice Fitting Removal and Installation
Instructions’’ in Ayres Corporation Service
Bulletin No. SB–AG–39, dated September 17,
1996. Do the inspection following FAA
Advisory Circular (AC) 43.13–1B, Chapter 5,
Section 4, Magnetic Particle Inspection, using
the wet particle method. You may obtain a
copy of AC 43.13–1B at https://www.faa.gov/
regulations_policies/. Caution: Firmly
support the wings during the inspection to
prevent movement of the wing front lower
spar caps when the splice blocks are
removed. This will allow easier realignment
of the splice block holes and the holes in the
wing front lower spar cap for bolt insertion
and prevent damage to the bolt hole. Damage
to the bolt hole inner surface or edge of the
bolt hole can cause cracks to begin
prematurely.
(ii) The inspection must be done by or
supervised by a Level 2 or Level 3 inspector
certified following the guidelines in FAA AC
65–31A. You may obtain a copy of AC 65–
31A at https://www.faa.gov/
regulations_policies/.
(iii) If using eddy current methods, a
procedure must be sent to the FAA, Atlanta
Aircraft Certification Office (ACO), for
approval before doing the inspection. Send
your proposed procedure to the FAA, Atlanta
ACO, Attn: Cindy Lorenzen, 1701 Columbia
Avenue, College Park, Georgia 30337. You
are not required to remove the splice block
for the eddy current inspections, unless
corrosion is visible. Eddy current inspection
3137
procedures previously approved under AD
2006–07–15, AD 2003–07–01, AD 2000–11–
16, AD 97–13–11, and/or AD 97–17–03
remain valid for this AD.
(iv) If you change the inspection method
used (magnetic particle or eddy current), the
TIS intervals for repetitive inspections are
based on the method used for the last
inspection.
(3) If airplanes have not yet reached the
threshold for the initial inspection required
in AD 2006–07–15, initially inspect
following the wing front lower spar cap
hours total TIS schedule below or within the
next 50 hours TIS after February 24, 2010
(the effective date of this AD), whichever
occurs later:
TABLE 2—INITIAL INSPECTION TIMES
Initially inspect upon accumulating
the following hours total TIS on
the wing front lower spar cap
Airplane group
(i) Group 1 ...........................................................................................................................................................
(ii) Group 2 ..........................................................................................................................................................
(iii) Group 3 ..........................................................................................................................................................
(iv) Group 5 .........................................................................................................................................................
(v) Group 6 ..........................................................................................................................................................
(vi) Any airplane with the entire Custom Kit CK–AG–41 installed ......................................................................
(4) Airplanes in all groups must meet the
following conditions before doing the
repetitive inspections required in paragraphs
(i)(5), (i)(6), or (i)(7) of this AD:
(i) No cracks have been found previously
on wing front lower spar cap; or
(ii) Small cracks have been repaired
through cold work (or done as an option if
never cracked) following Ayres Corporation
Service Bulletin No. SB–AG–39, dated
September 17, 1996; or
(iii) Small cracks have been repaired by
reaming the 1⁄4-inch bolt hole to 5⁄16 inches
diameter (or done as an option if never
cracked) following Ayres Corporation
Custom Kit No. CK–AG–29, Part I, dated
December 23, 1997; or
(iv) Small cracks have been repaired
through previous alternative methods of
compliance (AMOC); or
(v) Small cracks have been repaired by
installing Kaplan splice blocks, P/N 22515–
1/–3 or P/N 88–251 (or done as an option if
never cracked) following Quality Aerospace,
Inc. Custom Kit No. CK–AG–30, dated
December 6, 2001.
(5) Repetitively inspect Groups 1, 2, 3, and
6 airplanes that do not have ‘‘big butterfly’’
2,000 hours TIS.
1,400 hours TIS.
6,400 hours TIS.
1,000 hours TIS.
(A) S/N 5010R: 5,530 hours TIS.
(B) S/N 5038R: 5,900 hours TIS.
(C) S/N 5031R: 6,400 hours TIS.
(D) S/N 5047R: 6,400 hours TIS.
(E) S/N 5085R: 6,290 hours TIS.
2,000 hours TIS.
plates and lower splice plates, P/Ns 20211–
09 and 20211–11, installed following Ayres
Corporation Custom Kit No. CK–AG–29, Part
II, dated December 23, 1997; or that do not
have ‘‘big butterfly’’ plates and lower splice
plates, P/Ns 94418–5 and 94418–7 or P/Ns
94418–13 and 94418–15, installed following
Thrush Aircraft, Inc. Custom Kit No. CK–
AG–41, Revision A, dated March 8, 2007; and
meet the conditions in paragraph (i)(4) of this
AD. Follow the wing front lower spar cap
hours TIS compliance schedule below:
TABLE 3—REPETITIVE INSPECTION TIMES FOR AIRPLANE GROUPS 1, 2, 3, AND 6 WITHOUT ‘‘BIG BUTTERFLY’’ PLATES AND
LOWER SPLICE PLATES
Inspect within the following hours TIS
after the effective date of this AD,
Inspect thereafter at
intervals not to
exceed . . .
(i) Magnetic Particle inspection: ...........................................................................
(A) 350 or more hours TIS ............................................................................
(B) 175 through 349 hours TIS .....................................................................
(C) Less than 175 hours TIS ........................................................................
(ii) Eddy Current inspection: .................................................................................
(A) 500 or more hours TIS ............................................................................
(B) 275 through 499 hours TIS .....................................................................
(C) Less than 275 hours TIS ........................................................................
pwalker on DSK8KYBLC1PROD with RULES
When airplanes accumulate the following hours TIS on the wing front lower
spar cap since the last inspection required in AD 2006-07-15,
...............................................................
(A) 50 hours TIS.
(B) 75 hours TIS.
(C) upon accumulating 250 hours TIS.
...............................................................
(A) 50 hours TIS.
(B) 75 hours TIS.
(C) upon accumulating 350 hours TIS.
250 hours TIS.
(6) Repetitively inspect Groups 1, 2, 3, 5,
and 6 airplanes that have ‘‘big butterfly’’
plates and lower splice plates, P/Ns 20211–
09 and 20211–11, installed following Ayres
Corporation Custom Kit No. CK–AG–29, Part
VerDate Nov<24>2008
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II, dated December 23, 1997; or that have ‘‘big
butterfly’’ plates and lower splice plates,
P/Ns 94418–5 and 94418–7, or P/Ns 94418–
13 and 94418–15, installed following Thrush
Aircraft, Inc. Custom Kit No. CK–AG–41,
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350 hours TIS.
Revision A, dated March 8, 2007; and meet
the conditions in paragraph (i)(4) of this AD.
Follow the wing front lower spar cap hours
TIS compliance schedule below:
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Federal Register / Vol. 75, No. 12 / Wednesday, January 20, 2010 / Rules and Regulations
TABLE 4—REPETITIVE INSPECTIONS TIMES FOR AIRPLANE GROUPS 1, 2, 3, 5, AND 6 WITH ‘‘BIG BUTTERFLY’’ PLATES AND
LOWER SPLICE PLATES
When airplanes accumulate the following hours TIS on the wing front lower
spar cap since the last inspection required in AD 2006-07-15,
Inspect within the following hours TIS
after the effective date of this AD,
Inspect thereafter at
intervals not to
exceed . . .
(i) Magnetic particle inspection: ...........................................................................
(A) 650 or more hours TIS ............................................................................
(B) 375 through 649 hours TIS .....................................................................
(C) Less than 375 hours TIS ........................................................................
(ii) Eddy Current inspection: .................................................................................
(A) 900 or more hours TIS ............................................................................
(B) 550 through 899 hours TIS .....................................................................
(C) Less than 550 hours TIS ........................................................................
...............................................................
(A) 50 hours TIS.
(B) 75 hours TIS.
(C) upon accumulating 450 hours TIS.
...............................................................
(A) 50 hours TIS.
(B) 75 hours TIS.
(C) upon accumulating 625 hours TIS.
450 hours TIS.
Note 1: Group 5 airplanes had P/Ns 20211–
09 and 20211–11 installed at the factory.
(7) Repetitively inspect airplanes that
incorporate Thrush Aircraft, Inc. Custom Kit
No. CK–AG–41, Revision A, dated March 8,
2007, in its entirety that meet the conditions
625 hours TIS.
in paragraph (i)(4) of this AD. Follow the
wing front lower spar cap hours TIS
compliance schedule below:
TABLE 5—REPETITIVE INSPECTION TIMES FOR AIRPLANES WITH THRUSH AIRCRAFT, INC. CUSTOM KIT NO. CK–AG–41,
REVISION A, INCORPORATED IN ITS ENTIRETY
When using the following inspection methods,
Repetitively inspect at intervals not
to exceed . . .
(i) Magnetic particle inspection ............................................................................................................................
(ii) Eddy current inspection ..................................................................................................................................
900 hours TIS.
1,250 hours TIS.
(j) Initially replace the wing front lower
spar caps, P/Ns 20207–1, 20207–2, 20207–11,
20207–12, 20207–13, 20207–14, 20207–15, or
20207–16, at the times specified in Table 6
of this AD. Repetitively replace thereafter at
the life limit times specified in Table 7 of this
AD. Do the replacements as specified in
paragraph (l)(4) of this AD.
TABLE 6—INITIAL COMPLIANCE TIME FOR WING FRONT LOWER SPAR CAP REPLACEMENT
Replace the wing front lower spar
cap upon accumulating the
following hours TIS on the spar
cap after the effective date of this
AD
Total hours TIS on the wing front lower spar cap
pwalker on DSK8KYBLC1PROD with RULES
(i) Group 1 with a radial engine and more than 15,000 hours TIS ....................................................................
(ii) Group 1 with a radial engine and 12,000 to 15,000 hours TIS .....................................................................
(iii) Group 1 with a radial engine and 9,000 to 11,999 hours TIS ......................................................................
(iv) Group 1 with a radial engine and 7,400 to 8,999 hours TIS ........................................................................
(v) Group 1 with a radial engine and less than 7,400 hours TIS .......................................................................
(vi) Group 1 with a turbine engine and more than 14,000 hours TIS ................................................................
(vii) Group 1 with a turbine engine and 11,000 to 14,000 hours TIS .................................................................
(viii) Group 1 with a turbine engine and 8,000 to 10,999 hours TIS ..................................................................
(ix) Group 1 with a turbine engine and 4,200 to 7,999 hours TIS ......................................................................
(x) Group 1 with a turbine engine and less than 4,200 hours TIS .....................................................................
(xi) Group 2 with more than 9,000 hours TIS .....................................................................................................
(xii) Group 2 with 6,000 to 9,000 hours TIS .......................................................................................................
(xiii) Group 2 with 3,900 hours to 5,999 hours TIS ............................................................................................
(xiv) Group 2 with less than 3,900 hours TIS .....................................................................................................
(xv) Group 3 and 6 with more than 28,800 hours TIS ........................................................................................
(xvi) Group 3 and 6 with 27,800 to 28,799 hours TIS ........................................................................................
(xvii) Group 3 and 6 with less than 27,800 hours TIS ........................................................................................
(xviii) Group 5 with more than 8,000 hours TIS ..................................................................................................
(xix) Group 5 with 5,000 to 7,999 hours TIS ......................................................................................................
(xx) Group 5 with 2,400 to 4,999 hours TIS .......................................................................................................
(xxi) Group 5 with less than 2,400 hours TIS .....................................................................................................
500 hours.
1,000 hours.
1,500 hours.
2,000 hours.
Use Table 7(xxii).
500 hours.
1,000 hours.
1,500 hours.
2,000 hours.
Use Table 7(xxiii).
500 hours.
1,000 hours.
1,500 hours.
Use Table 7(xxiv).
500 hours.
1,000 hours.
Use Table 7(xxv).
500 hours.
1,000 hours.
1,500 hours.
Use Table 7(xxvi).
TABLE 7—WING FRONT LOWER SPAR CAP LIFE LIMITS
Airplane group
Replace wing front lower spar cap
upon the accumulation of the
following hours TIS on the spar
cap:
(xxii) Group 1 with a radial engine ......................................................................................................................
9,400 hours TIS.
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3139
TABLE 7—WING FRONT LOWER SPAR CAP LIFE LIMITS—Continued
Replace wing front lower spar cap
upon the accumulation of the
following hours TIS on the spar
cap:
Airplane group
(xxiii) Group 1 with a turbine engine ...................................................................................................................
(xxiv) Group 2 ......................................................................................................................................................
(xxv) Groups 3 and 6 ..........................................................................................................................................
(xxvi) Group 5 ......................................................................................................................................................
(ii) Equivalent Group 1 hours TIS = 9,400
× Usage Factor
(2) For airplanes that were originally Group
3 airplanes and later modified by installing
pwalker on DSK8KYBLC1PROD with RULES
(i) Usage factor =
(ii) Equivalent Group 1 hours TIS = 6,200
× Usage Factor
(3) When the equivalent Group 1 hours TIS
on the wing front lower spar cap equals the
life limit of 9,400 hours TIS if a radial piston
engine is installed or reaches 6,200 hours TIS
if a turbine engine is installed, the wing front
lower spar cap must be replaced. Use Table
6 if over the life limit.
(4) See the appendix to this AD for
examples of how to calculate the applicable
life limit.
(l) If any cracks are found during any
inspection required by this AD, you must
repair the cracks or replace the wing front
lower spar cap before further flight.
(1) Use the cold work process to ream out
small cracks as defined in Ayres Corporation
Service Bulletin No. SB–AG–39, dated
September 17, 1996, and deburr the bolt hole
edges with the splice blocks removed after
cold work is performed; or
(2) If the crack is found in a 1⁄4-inch bolt
hole, ream the 1⁄4-inch bolt hole to 5⁄16 inches
diameter as defined in Part I of Ayres
Corporation Custom Kit No. CK–AG–29,
dated December 23, 1997; or
(3) Install Kaplan splice blocks, P/N
22515–1/3 or P/N 88–251, following Quality
VerDate Nov<24>2008
15:59 Jan 19, 2010
Jkt 220001
(1) For airplanes that were originally Group
3 airplanes and later modified by installing
a piston engine of greater than 600
horsepower and/or a hopper capacity of
greater than 410 gallons, calculate the
equivalent Group 1 hours TIS on each spar
cap as follows:
Total hrs. on cap pre-mod.
Additional hrs. on cap post-mod.
+
28, 800
9, 400
a turbine engine of greater than 600
horsepower, with or without installing a
hopper with greater than 410 gallon capacity,
calculate the equivalent Group 1 hours TIS
on each spar cap as follows:
Total hrs. on cap pre-mod.
Additional hrs. on cap post-mod.
+
28, 800
6, 200
Aerospace, Inc. Custom Kit No. CK–AG–30,
dated December 6, 2001; or
(4) Replace the affected wing front lower
spar cap following an FAA-approved
procedure. Contact the FAA at the address in
paragraph (t) of this AD to obtain an FAAapproved replacement procedure unless
previously provided by the manufacturer at
delivery of the airplanes. An alternative to
replacing just the affected wing front lower
spar cap is to replace both wing front lower
spar caps and the surrounding structure
following Thrush Aircraft, Inc. Custom Kit
No. CK–AG–41, Revision A, dated March 8,
2007. Another alternative to replacing just
the affected wing front lower spar cap is to
replace both wing front lower spar caps and
the surrounding structure following Avenger
Aircraft and Services FAA STC SA03654AT
for Avenger Extended Performance Front
Spar Enhancement Kit. You may obtain a
copy of FAA STC SA03654AT at https://
www.faa.gov/aircraft/air_cert/
design_approvals/stc/. If you chose to install
Thrush Custom Kit No. CK–AG–41, the FAA
recommends installing Custom Kit No. CK–
AG–41, Revision A, in its entirety although
this is not mandatory. The additional
structure provided in Thrush Aircraft, Inc.
Custom Kit No. CK–AG–41, Revision A,
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dated March 8, 2007, will provide a greater
level of safety than the minimum acceptable
level of safety provided by replacing just the
wing front lower spar cap. If choosing to
install the Avenger FAA STC kit, it is
mandatory to install the entire FAA STC kit.
(m) If a crack is found, the reaming
associated with the cold work process may
remove a crack if it is small enough. Some
aircraft owners/operators were issued
AMOCs with AD 97–17–03 to ream the 1⁄4inch bolt hole to 5⁄16 inches diameter to
remove small cracks. Ayres Corporation
Custom Kit No. CK–AG–29, Part I, dated
December 23, 1997, also provides procedures
to ream the 1⁄4-inch bolt hole to 5⁄16 inches
diameter, which may remove a small crack.
Resizing the holes to the required size to
install a Kaplan splice block may also remove
small cracks. If you use any of these methods
to remove cracks and the airplane is reinspected before further flight and no cracks
are found, you may continue to follow the
repetitive inspection intervals for your
airplane listed in paragraphs (i)(5), (i)(6), or
(i)(7) of this AD.
(n) For all inspection methods (magnetic
particle or eddy current), hours TIS for initial
and repetitive inspection intervals and wing
front lower spar cap life limit start over when
E:\FR\FM\20JAR1.SGM
20JAR1
ER20JA10.001</MATH>
(i) Usage factor =
modified with a hopper of a capacity more
than 410 gallons, a piston engine greater than
600 horsepower, or a gas turbine engine
greater than 600 horsepower, is a Group 1
airplane for the purposes of this AD. Replace
the wing front lower spar caps using the
following formulas.
ER20JA10.000</MATH>
Note 2: There is evidence of sharp, uneven
edges on the spar cap bolt holes that resulted
from the manufacturing process in Group 5
airplanes. Once the original wing front lower
spar caps are replaced, the life limit
increases.
(k) As previously stated in paragraph (f) of
this AD, any Group 3 airplane that has been
6,200 hours TIS.
5,400 hours TIS.
28,800 hours TIS.
3,900 hours TIS with original wing
front lower spar cap P/N 20207–
11 or P/N 20207–12.
5,400 hours TIS after original wing
front lower spar cap has been
replaced with any P/N 20207-xx
wing front lower spar cap.
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Federal Register / Vol. 75, No. 12 / Wednesday, January 20, 2010 / Rules and Regulations
the wing front lower spar cap is replaced
with a new P/N 20207–1, 20207–2, 20207–
11, 20207–12, 20207–13, 20207–14, 20207–
15, or 20207–16. These wing front lower spar
caps must be inspected as specified in
paragraphs (i)(3), (i)(5), (i)(6), and (i)(7) of
this AD.
(1) If the wings or wing front lower spar
caps were replaced with new or used wings
or wing front lower spar caps during the life
of the airplane and the logbook records
positively show the hours TIS of the
replacement wings or wing front lower spar
caps, then initially inspect at applicable
times specified in paragraph (i)(3) of this AD.
Repetitively inspect thereafter at intervals
specified paragraphs (i)(5), (i)(6), or (i)(7) of
this AD. Replace the wing front lower spar
caps upon reaching the life limit specified in
Table 7 of this AD.
(2) If the wings or wing front lower spar
caps were replaced with new or used wings
or wing front lower spar caps during the life
of the airplane and logbook records do not
positively show the hours TIS of the
replacement wings or wing front lower spar
caps, then inspect within 50 hours TIS after
February 24, 2010 (the effective date of this
AD), unless already done. Repetitively
inspect thereafter at intervals specified in
paragraphs (i)(5), (i)(6), or (i)(7) of this AD.
Replace the wing front lower spar caps
within 500 hours TIS after February 24, 2010
(the effective date of this AD).
(3) If both wing front lower spar caps are
replaced by installing the entire Thrush
Aircraft, Inc. Custom Kit No. CK–AG–41,
Revision A, dated March 8, 2007, then
initially inspect at 2,000 hours TIS as shown
in paragraph (i)(3) of this AD. Repetitively
inspect thereafter at intervals specified in
paragraph (i)(7) of this AD. Replace the wing
front lower spar caps at times specified in
paragraph (i)(8) of this AD.
(o) Any wing front lower spar cap that is
removed and is at or beyond the replacement
time specified in this AD must be disposed
of following the procedures in 14 CFR Part
43.10.
(p) Replacement times start over when the
wing front lower spar cap is replaced with a
new P/N 20207–1, 20207–2, 20207–11,
20207–12, 20207–13, 20207–14, 20207–15, or
20207–16. These wing front lower spar caps
are now life-limited parts and must be
replaced upon the accumulation of the hours
TIS specified in Table 7 of this AD.
(q) Report any cracks you find within 10
days after the cracks are found or within 10
days after February 24, 2010 (the effective
date of this AD), whichever occurs later.
Send your report to Cindy Lorenzen,
Aerospace Engineer, ACE–115A, Atlanta
ACO, 1701 Columbia Avenue, College Park,
Georgia 30337; telephone: (404) 474–5524;
facsimile: (404) 474–5606; e-mail:
cindy.lorenzen@faa.gov. The Office of
Management and Budget (OMB) approved
the information collection requirements
contained in this regulation under the
provisions of the Paperwork Reduction Act
and assigned OMB Control Number 2120–
0056. Include in your report the following
information:
(1) Aircraft model and serial number;
(2) Engine model;
VerDate Nov<24>2008
15:59 Jan 19, 2010
Jkt 220001
(3) Aircraft hours TIS;
(4) Left and right wing front lower spar cap
hours TIS;
(5) Hours TIS on the spar cap since last
inspection;
(6) Crack location and size;
(7) Procedure (magnetic particle,
ultrasonic, or eddy current) used for the last
inspection;
(8) Description of any previous
modifications and hours TIS when the
modification was done, such as engine model
change, installation of winglets, hopper
capacity increase, cold working procedure
done on bolt holes, installation of butterfly
plates, or installation of Thrush Aircraft, Inc.
Custom Kit No. CK–AG–41.
(r) Installation of the replacement wing
front lower spar caps and other modification
parts that are approved by FAA STC
SA03654AT, Installation of Avenger
Extended Performance Front Spar
Enhancement Kit (new wing front spar lower
caps, center splice and doublers), in
accordance with Part II of Avenger Master
Data List AAS–MDL–08–001, Revision B,
dated November 26, 2008, terminates the
actions required by this AD. The installation
of FAA STC SA03654AT is an alternative to
replacing the wing front lower spar caps with
Ayres/Thrush wing front lower spar caps.
Special Flight Permits
(s) Under 14 CFR part 39.23, we are
limiting the special flight permits for this AD
by the following conditions:
(1) The hopper is empty;
(2) Vne is reduced to 126 miles per hour
(109 knots) indicated airspeed (IAS); and
(3) Flight into known turbulence is
prohibited.
Alternative Methods of Compliance
(AMOCs)
(t) The Manager, Atlanta Aircraft
Certification Office, (ACO) FAA, ATTN:
Cindy Lorenzen, Aerospace Engineer, ACE–
115A, Atlanta ACO, 1701 Columbia Avenue,
College Park, Georgia 30337; telephone: (404)
474–5524; facsimile: (404) 474–5606; e-mail:
cindy.lorenzen@faa.gov; or William O.
Herderich, Aerospace Engineer, ACE–117A,
Atlanta ACO, 1701 Columbia Avenue,
College Park, Georgia 30337; telephone: (404)
474–5547; facsimile: (404) 474–5606; e-mail:
william.o.herderich@faa.gov, has the
authority to approve AMOCs for this AD, if
requested using the procedures found in 14
CFR 39.19. Before using any approved AMOC
on any airplane to which the AMOC applies,
notify your appropriate principal inspector
(PI) in the FAA Flight Standards District
Office (FSDO), or lacking a PI, your local
FSDO.
(u) AMOCs approved for AD 2006–07–15,
AD 2003–07–01, AD 2000–11–16, AD 97–13–
11, and/or AD 97–17–03 are approved as
AMOCs for this AD except for those
pertaining to ultrasonic inspection methods.
Material Incorporated by Reference
(v) You must use Ayres Corporation
Service Bulletin No. SB–AG–39, dated
September 17, 1996; Ayres Corporation
Custom Kit No. CK–AG–29, dated December
23, 1997; Quality Aerospace, Inc. Custom Kit
No. CK–AG–30, dated December 6, 2001;
PO 00000
Frm 00016
Fmt 4700
Sfmt 4700
Thrush Aircraft, Inc. Custom Kit No. CK–
AG–41, Revision A, dated March 8, 2007; and
Part II of Avenger Master Data List AAS–
MDL–08–001, Revision B, dated November
26, 2008, to do the actions required by this
AD, unless the AD specifies otherwise.
(1) The Director of the Federal Register
approved the incorporation by reference of
Thrush Aircraft, Inc. Custom Kit No. CK–
AG–41, Revision A, dated March 8, 2007, and
Part II of Avenger Master Data List AAS–
MDL–08–001, Revision B, dated November
26, 2008, under 5 U.S.C. 552(a) and 1 CFR
part 51.
(2) On May 20, 2003 (68 FR 15653), the
Director of the Federal Register approved the
incorporation by reference of Quality
Aerospace, Inc. Custom Kit No. CK–AG–30,
dated December 6, 2001.
(3) On July 25, 2000 (65 FR 36055), the
Director of the Federal Register approved the
incorporation by reference of Ayres
Corporation Service Bulletin No. SB–AG–39,
dated September 17, 1996; and Ayres
Corporation Custom Kit No. CK–AG–29,
dated December 23, 1997.
(4) For service information identified in
this AD, contact Thrush Aircraft, Inc., 300
Old Pretoria Road, P.O. Box 3149, Albany,
Georgia 31706–3149, Internet: https://
www.thrushaircraft.com. To obtain
information about Avenger Master Data List
AAS–MDL–08–001 and the optional
installation of FAA STC SA03654AT, contact
Avenger Aircraft and Services, 103 N. Main
Street, Suite 106, Greenville, South Carolina
29601, Internet: https://
www.avengeraircraft.com.
(5) You may review copies of the service
information incorporated by reference for
this AD at the FAA, Central Region, Office of
the Regional Counsel, 901 Locust, Kansas
City, Missouri 64106. For information on the
availability of this material at the Central
Region, call (816) 329–3768.
(6) You may also review copies of the
service information incorporated by reference
for this AD at the National Archives and
Records Administration (NARA). For
information on the availability of this
material at NARA, call (202) 741–6030, or go
to: https://www.archives.gov/federal_register/
code_of_federal_regulations/
ibr_locations.html.
Appendix to AD 2009–26–11
The following are examples of calculating
equivalent Group 1 hours.
Example 1: S/N xxx was originally a Group
3 airplane; later it was modified with a
Wright R–1820–71, 1200 horsepower, radial
engine when the wing front lower spar caps
had 15,700 hours TIS on them. The wing
front lower spar caps have accumulated an
additional 8,200 hours since the engine
conversion for a total of 23,900 hours TIS on
the wing front lower spar caps.
Usage Factor = 15,700 hours/28,800 + 8,200
hours/9,400 = 1.417
Equivalent Group 1 hours = 9,400 × 1.417 =
13,320 hours.
The wing front lower spar caps will need
to be replaced within the next 1,000 hours
TIS after the effective date of this AD as
determined by Table 6 for a Group 1 airplane
E:\FR\FM\20JAR1.SGM
20JAR1
Federal Register / Vol. 75, No. 12 / Wednesday, January 20, 2010 / Rules and Regulations
with a radial engine with between 12,000 and
15,000 hours TIS.
Example 2: S/N yyy was originally a Group
3 airplane; later it was modified with a
PT6A–34, 750 horsepower, turbine engine
when the wing front lower spar caps had
5,300 hours TIS on them. The wing front
lower spar caps now have 7,700 hours TIS.
Usage Factor = 5,300 hours/28,800 + (7,700
¥ 5,300)/6,200 = 0.571
Equivalent Group 1 hours = 6,200 × 0.571 =
3,540 hours.
The wing front lower spar caps will need
to be replaced at 6,200 equivalent Group 1
total hours TIS, which is within the next
2,660 hours TIS (6,200 ¥ 3,540 = 2,660).
Issued in Kansas City, Missouri, on January
8, 2010.
Margaret Kline,
Acting Manager, Small Airplane Directorate,
Aircraft Certification Service.
[FR Doc. 2010–594 Filed 1–19–10; 8:45 am]
BILLING CODE 4910–13–P
cabin occupants or maintenance or
other support personnel.
DATES: This AD is effective February 4,
2010.
We must receive any comments on
this AD by March 8, 2010.
ADDRESSES: You may send comments by
any of the following methods:
• Federal eRulemaking Portal: Go to
https://www.regulations.gov. Follow the
instructions for submitting comments.
• Fax: 202–493–2251.
• Mail: U.S. Department of
Transportation, Docket Operations, M–
30, West Building Ground Floor, Room
W12–140, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.
• Hand Delivery: U.S. Department of
Transportation, Docket Operations, M–
30, West Building Ground Floor, Room
W12–140, 1200 New Jersey Avenue, SE.,
Washington, DC 20590, between 9 a.m.
and 5 p.m., Monday through Friday,
except Federal holidays.
DEPARTMENT OF TRANSPORTATION
Examining the AD Docket
Federal Aviation Administration
You may examine the AD docket on
the Internet at https://
www.regulations.gov; or in person at the
Docket Management Facility between 9
a.m. and 5 p.m., Monday through
Friday, except Federal holidays. The AD
docket contains this AD, the regulatory
evaluation, any comments received, and
other information. The street address for
the Docket Office (telephone 800–647–
5527) is in the ADDRESSES section.
Comments will be available in the AD
docket shortly after receipt.
FOR FURTHER INFORMATION CONTACT:
Nicholas Wilson, Aerospace Engineer,
Cabin Safety and Environmental
Systems Branch, ANM–150S, Seattle
Aircraft Certification Office, FAA, 1601
Lind Avenue, SW., Renton, Washington
98057–3356; telephone (425) 917–6476;
fax (425) 917–6590.
SUPPLEMENTARY INFORMATION:
14 CFR Part 39
[Docket No. FAA–2010–0029; Directorate
Identifier 2009–NM–262–AD; Amendment
39–16179; AD 2009–21–10 R1]
RIN 2120–AA64
Airworthiness Directives; AVOX
Systems and B/E Aerospace Oxygen
Cylinder Assemblies, as Installed on
Various Transport Airplanes
pwalker on DSK8KYBLC1PROD with RULES
AGENCY: Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Final rule; request for
comments.
SUMMARY: The FAA is revising an
existing airworthiness directive (AD),
which applies to certain AVOX Systems
and B/E Aerospace oxygen cylinder
assemblies, as installed on various
transport airplanes. That AD currently
requires removing certain oxygen
cylinder assemblies from the airplane.
This AD removes certain oxygen
cylinder part numbers from the
applicability. This AD was prompted by
the reported rupture of a high-pressure
gaseous oxygen cylinder, which had
insufficient strength characteristics due
to improper heat treatment. We are
issuing this AD to prevent an oxygen
cylinder from rupturing, which,
depending on the location, could result
in structural damage and rapid
decompression of the airplane, damage
to adjacent essential flight equipment,
deprivation of the necessary oxygen
supply for the flightcrew, and injury to
VerDate Nov<24>2008
15:59 Jan 19, 2010
Jkt 220001
Discussion
On November 25, 2009, we issued AD
2009–21–10, amendment 39–16049 (74
FR 63063, December 2, 2009). That AD
applies to certain AVOX Systems and B/
E Aerospace oxygen cylinder
assemblies, as installed on various
transport airplanes. That AD requires
removing certain oxygen cylinder
assemblies from the airplane. That AD
was prompted by the reported rupture
of a high-pressure gaseous oxygen
cylinder, which had insufficient
strength characteristics due to improper
heat treatment. The actions specified in
that AD are intended to prevent an
oxygen cylinder from rupturing, which,
depending on the location, could result
in structural damage and rapid
PO 00000
Frm 00017
Fmt 4700
Sfmt 4700
3141
decompression of the airplane, damage
to adjacent essential flight equipment,
deprivation of the necessary oxygen
supply for the flightcrew, and injury to
cabin occupants or maintenance or
other support personnel.
Actions Since AD Was Issued
Since we issued AD 2009–21–10, we
have been notified that its applicability
(in paragraph (c)) erroneously includes
oxygen cylinder assemblies having part
numbers B43570–3 and B43570–5.
Those oxygen cylinder assemblies are
manufactured from composite material,
instead of steel, and the erroneous part
numbers do not correspond to any serial
numbers listed in the AD. Composite
oxygen tanks are not subject to the
identified unsafe condition. These part
numbers have been removed from Table
1 of this AD.
We have also been notified that serial
numbers K617383 through K617423
inclusive and K757064 through
K757066 inclusive have been
withdrawn from service. These serial
numbers have been removed from Table
3 of this AD.
FAA’s Determination and Requirements
of This AD
Certain affected airplanes have been
approved by the aviation authorities of
other countries, and are approved for
operation in the United States.
The unsafe condition described
previously is likely to exist or develop
in other products of these same type
designs. For this reason, we are issuing
this AD to revise AD 2009–21–10. This
new AD retains the requirements of the
existing AD, but removes part numbers
B43570–3 and B43570–5 from the
applicability of this AD, and removes
certain serial numbers from Table 3 of
this AD.
Additional Change to AD
We have revised this AD to identify
the legal name of certain manufacturers
as published in the most recent type
certificate data sheet for the affected
airplane models.
FAA’s Justification and Determination
of the Effective Date
This AD addresses the consequences
of the potential rupture of certain
oxygen cylinder assemblies. Because of
our requirement to promote safe flight of
civil aircraft and thus the critical need
to ensure the proper functioning of the
oxygen cylinders and the short
compliance time involved with this
action, this AD must be issued
immediately.
Because an unsafe condition exists
that requires the immediate adoption of
E:\FR\FM\20JAR1.SGM
20JAR1
]]>Agencies
[Federal Register Volume 75, Number 12 (Wednesday, January 20, 2010)]
[Rules and Regulations]
[Pages 3127-3141]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-594]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-27862; Directorate Identifier 2007-CE-036-AD;
Amendment 39-16150; AD 2009-26-11]
RIN 2120-AA64
Airworthiness Directives; Thrush Aircraft, Inc. Model 600 S2D and
S2R Series Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: We are adopting a new airworthiness directive (AD) to
supersede AD (AD) 2006-07-15, which applies to Thrush Aircraft, Inc.
Model 600 S2D and S2R (S-2R) series airplanes (type certificate
previously held by Quality Aerospace, Inc. and Ayres Corporation). AD
2006-07-15 currently requires repetitive inspections of the 1/4-inch
and 5/16-inch bolt hole areas on the wing front lower spar caps for
fatigue cracking; replacement or repair of any wing front lower spar
cap where fatigue cracks are found; and reporting of any fatigue cracks
found to the FAA. AD 2006-07-15 also puts the affected airplanes into
groups for compliance time and applicability purposes. Since we issued
AD 2006-07-15, FAA analysis reveals that inspections are not detecting
all existing cracks and shows the incidences of undetected cracks will
increase as the airplanes age. Consequently, this AD retains the
actions of AD 2006-07-15 and imposes a life limit on the wing front
lower spar caps that requires replacement of the wing front lower spar
caps when the life limit is reached. This AD also changes the
requirements and applicability of the groups discussed above and
removes the ultrasonic inspection method. We are issuing this AD to
prevent wing front lower spar cap failure caused by undetected fatigue
cracks. Such failure could result in loss of a wing in flight.
DATES: This AD becomes effective on February 24, 2010.
On February 24, 2010, the Director of the Federal Register approved
the incorporation by reference of Thrush Aircraft, Inc. Custom Kit No.
CK-AG-41, Revision A, dated March 8, 2007, listed in this AD.
As of May 20, 2003 (68 FR 15653), the Director of the Federal
Register approved the incorporation by reference of Quality Aerospace,
Inc. Custom Kit No. CK-AG-30, dated December 6, 2001, listed in this
AD.
As of July 25, 2000 (65 FR 36055), the Director of the Federal
Register approved the incorporation by reference of Ayres Corporation
Service Bulletin No. SB-AG-39, dated September 17, 1996; and Ayres
Corporation Custom Kit No. CK-AG-29, dated December 23, 1997, listed in
this AD.
ADDRESSES: To get the service information identified in this AD,
contact Thrush Aircraft, Inc., 300 Old Pretoria Road, P.O. Box 3149,
Albany, Georgia 31706-3149. The service
[[Page 3128]]
information is also available on the Internet at https://www.thrushaircraft.com.
To view the AD docket, go to U.S. Department of Transportation,
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200
New Jersey Avenue, SE., Washington, DC 20590, or on the Internet at
https://www.regulations.gov. The docket number is FAA-2007-27862;
Directorate Identifier 2007-CE-036-AD.
FOR FURTHER INFORMATION CONTACT:
--Cindy Lorenzen, Aerospace Engineer, ACE-115A, Atlanta Aircraft
Certification Office, 1701 Columbia Avenue, College Park, Georgia
30337; telephone: (404) 474-5524; facsimile: (404) 474-5606; e-mail:
cindy.lorenzen@faa.gov; or
--William O. Herderich, Aerospace Engineer, ACE-117A, Atlanta Aircraft
Certification Office, 1701 Columbia Avenue, College Park, Georgia
30337; telephone: (404) 474-5547; facsimile: (404) 474-5606; e-mail:
william.o.herderich@faa.gov.
SUPPLEMENTARY INFORMATION:
Discussion
On April 27, 2009, we issued a proposal to amend part 39 of the
Federal Aviation Regulations (14 CFR part 39) to include an AD that
would apply to certain Thrush Aircraft, Inc. Model 600 S2D and S2R (S-
2R) series airplanes (type certificate previously held by Quality
Aerospace, Inc. and Ayres Corporation). This proposal was published in
the Federal Register as a notice of proposed rulemaking (NPRM) on May
4, 2009 (74 FR 20431). The NPRM proposed to supersede AD 2006-07-15,
Amendment 39-14542 (71 FR 19788, April 17, 2006) with a new AD that
would:
Retain the actions of AD 2006-07-15;
Add life limits for the wing front lower spar caps;
Lower the initial and repetitive inspection times for
Group 5 airplanes;
Correct some airplane Group classifications;
Add an airplane to the Applicability section; and
Remove the use of ultrasonic inspection methods.
For replacement of the wing front lower spar caps, the initial
compliance time for all airplanes will be at least an additional 500
hours time-in-service (TIS) after the effective date of this AD.
Calculated from actual flight hour data from 285 S2R series airplanes,
500 hours TIS equates to the average yearly operational time. The
compliance schedules should give owner/operators enough time to
schedule the replacement of the wing front lower spar caps.
Although not required in this AD, we recommend installing ``big
butterfly'' and lower splice plates, P/N 20211-09 and P/N 20211-11, or
Thrush Aircraft, Inc. Custom Kit No. CK-AG-41, Revision A, since they
increase the strength of the wing beyond the minimum safety standards.
Comments
We provided the public the opportunity to participate in developing
this AD. The following presents the comments received on the proposal
and FAA's response to each comment:
Comment Issue No. 1: Extend Compliance Time To Replace the Spar Caps
Marc Fries states that a large portion of the affected airplanes
will need to address a spar replacement within a very short period of
time, overwhelming a limited number of repair facilities. Mr. Fries
also states that most operators have a short ``down time'' during their
season in which to do this type of repair, and many operators will run
out of flying hours before a repair facility can do the work or even
get the kits from the factory.
Mr. Fries requests an extension of the compliance time because
there are a limited number of repair facilities, and the replacement
parts may not be available immediately. Mr. Fries also requests to
insert into the AD an allowance for an extension of the compliance time
while continuing the spar cap inspections.
We do not agree with the commenter. As stated in the NPRM,
allowance for the compliance time based on the limited number of repair
facilities and the limited availability of replacement parts has
already been made. For airplanes that have already exceeded the life
limit replacement time for the wing front lower spar caps, the minimum
compliance time for those with the highest hours TIS, which are the
airplanes with the highest risk of spar cap failure, is 500 hours TIS.
Five hundred hours TIS equates to an average year of operation for
these airplanes. Airplanes that have exceeded the life limit
replacement time, but are not at the highest level of risk, will be
allowed an even longer compliance time of 1,000 hours TIS, 1,500 hours
TIS, or 2,000 hours TIS based on the current number of hours TIS on the
wing front lower spar caps. Airplanes that have not yet reached the
life limit replacement time are allowed a minimum of 2,000 hours TIS to
comply with the AD. These compliance times result in an average
operator having at least one year to comply with the AD; however, most
operators will have much longer than one year to replace the wing front
lower spar caps. These graduated compliance times should allow enough
time for adequate supply of parts and repair facility availability.
We are not changing the final rule AD action based on this comment.
Comment Issue No. 2: Withdraw the AD
Charles Brumley states that the pilot should be allowed to make his
own decision whether a new spar cap is needed and requests an
alternative to this AD.
Mr. Brumley further states that he believes the AD is unnecessary
for the following reasons:
If the pilot is involved in the maintenance of the
airplane, then the pilot can make an informed decision about whether or
not to install a new spar cap and whether or not the aircraft is in a
condition for safe operation;
The AD will cause undue economic hardship on the airplane
operators and the farms that use aerial application services;
There have only been a few cracks found, i.e., that there
is not enough service history to support issuance of an AD; and
The large butterfly plates are adequate to ensure safety
of the pilot until a spar cap crack is found.
We infer this as a request for the FAA to withdraw the AD.
We do not agree with the commenter. While the commenter may have
maintained his airplane adequately, the formation of fatigue cracks
mainly relates to the airplane's design and operation. Replacement of
the wing front lower spar caps when they have reached their life limits
is currently the only means known to the FAA to address the unsafe
condition.
We have extensive crack data that currently shows 176 wings on 123
airplanes had cracks in the wing front lower spar caps. As the
incidences of cracking increase, which has occurred in the Thrush
airplanes, the chance of an existing crack not being detected during an
inspection increases. Airplanes with cracks in the wing front lower
spar caps are unable to meet ultimate strength requirements, which
could lead to a wing failure. The only known way of mitigating this
risk is to replace the wing front lower spar caps.
There are already procedures in place for owner/operators to
request an alternative to any AD. Use the alternative method of
compliance (AMOC) procedures provided in this AD
[[Page 3129]]
to request an AMOC. The request for an AMOC must include any
substantiating information, such as stress and fatigue data. The AMOC
will be approved if we find it provides an acceptable level of safety.
We are not changing the final rule AD action based on this comment.
Comment Issue No. 3: Adjusted Life Limits Based on Environmental
Conditions
Avenger Aircraft and Services (Avenger) states the life limits for
the wing front lower spar caps should be adjusted if environmental
conditions were not taken into account when determining the life
limits. The commenter states that metal fatigue is influenced by
environmental conditions.
We do not agree with the commenter's request to adjust the life
limits. We did take environmental conditions into consideration during
our analysis for determining the life limits. The risk-based analysis
used by the FAA used actual reported crack data from in-service
airplanes. These in-service data came from airplanes operated in a
variety of environments; therefore, the raw data used in the FAA's
analysis include the effects caused by environmental conditions.
We are not changing the final rule AD action based on this comment.
Comment Issue No. 4: Adjust Life Limits Based on Crack Sizes
Avenger states that the life limit of the wing front lower spar cap
could be much shorter if crack sizes are taken into account during the
risk assessment. Avenger also states that this can be particularly
significant when some fleet crack sizes may have exceeded the critical
size without failing due to the airplane not exceeding limit load at
that particular time.
We do not agree with the commenter's request. Although we did not
include the crack size in our analysis, we did use a statistical
approach and took into account the TIS on the wing front lower spar cap
when the crack was found and reported to the FAA. There are other
factors in place in the AD to mitigate the risk associated with not
using crack size to determine the life limit of the wing front lower
spar caps. We determined a life limit for continued operational safety
of the S2R fleet and did not propose a life limit as defined in FAA
guidance for type certification of newly certificated airplanes. Our
analysis of the crack data, which includes allowances for both the
statistically significant amount of crack data on the Thrush fleet and
the existence of an inspection program for the wing front lower spar
caps, yielded the life limits times for the wing front lower spar caps
shown in the NPRM.
We are not changing the final rule AD action based on this comment.
Comment Issue No. 5: Remove Magnetic Particle Inspection Method
Avenger states that the flaw size that can be detected by the
magnetic particle inspection method is 0.69 inches, which is in excess
of the flaw size that would allow the wing front lower spar cap to
continue to carry limit load.
Avenger states, therefore, magnetic particle inspections should not
be utilized as a valid inspection method and should be removed from the
AD.
We do not agree with the commenter. The magnetic particle
inspection interval was originally set at 500 hours TIS by AD 2000-11-
16 and was based on crack growth analysis provided by Ayres Corporation
(Ayres). We accepted Ayres' proposed usage of U.S. Air Force data from
Report AFWAL 3-5-852, which showed a reliably detectable crack size (90
percent probability/95 percent confidence) of 0.12 inch when using
magnetic particle inspection methods. Using this detectable crack size
with a repetitive inspection of 500 hours TIS allowed for at least two
inspections to occur after crack initiation and prior to a crack
reaching its critical size. As the fleet aged and as more cracks
occurred in-service, the risk to the fleet increased. To help mitigate
this risk, we doubled the frequency of the inspections required in AD
2006-07-15. In this AD we are requiring inspections every 250 hours
TIS, which allows for four chances of detecting a crack based on the
data originally used by Ayres. This same 250-hour TIS inspection
interval, along with imposing a wing front lower spar cap life limit to
further mitigate risk, was included in the proposed AD. The detectable
crack size of 0.12 inch used by Ayres is very near the values of
detectable size currently suggested for use by the FAA (Ref. Website
sponsored by the FAA in conjunction with Iowa State University https://www.cnde.iastate.edu/faa-casr/engineers/) of 0.13 to 0.15
inch. With the added conservatism of four inspections to detect cracks
before reaching a critical crack size, when two inspections are what is
normally required in a more ideal environment, the inspection interval
in this AD is well within the current guidelines.
We are not changing the final rule AD action based on this comment.
Comment Issue No. 6: Require Calibration Standards and Level 2 NDT
Personnel To Perform Eddy Current Inspections
Avenger states that calibration standards and Level 2 Non-
destructive Testing (NDT) personnel are necessary to achieve
reliability and repeatability in the inspections. These calibration
standards are designed to replicate the structure being inspected with
simulated flaws and are used every time as a setup tool by the
inspector prior to conducting the on-aircraft inspection. Utilization
of these standards is the current practice by all major aircraft
manufacturers and should be required for the Thrush inspections in
order to ensure a 90 percent probability of detection. In addition, the
inspectors should be fully certified Level 2 NDT personnel with bolt
hole eddy current qualifications.
We do not agree with the commenter's request that a change is
needed to the AD. This AD and the ADs that this AD supersedes allow for
eddy current inspection procedures to be approved only through the
FAA's Aircraft Certification Office (ACO). The FAA ACO already requires
each procedure to have the correct type of calibration standard as this
is a basic requirement for ensuring a good inspection. The FAA ACO has
not and will not approve an eddy current inspection procedure that does
not include a requirement to use only Level 2, or even more qualified
Level 3, certified NDT inspectors for these eddy current inspections.
We are not changing the final rule AD action based on this comment.
Comment Issue No. 7: Allow Installing Supplemental Type Certificate
(STC) SA03654AT as a Terminating Action in This AD
Avenger states that a solution that was not available at the time
the proposed AD was written is now currently on the market. Avenger
requests that the following information be included in the AD. This
solution is the Avenger STC SA03654AT Avenger Extended Performance
Front Spar Enhancement Kit.
STC SA03654AT installs FAA-approved replacement wing front lower
spar caps for all airplanes that are the subject of this AD, except for
Model S2D airplanes. The replacement spars have a life limit of 40,000
hours TIS with a parts cost of $40,000 and an installation cost of
$25,500.
Avenger's FAA STC replacement kit includes the following:
2 lower wing front lower spar caps (made from stainless
steel, not 4000 series steel);
[[Page 3130]]
2 front spar web doublers;
1 large butterfly plate (redesigned);
2 larger splice blocks (redesigned); and
All associated hardware for installation.
Avenger requests that the AD be amended to include the installation
of the Avenger Extended Performance (AXP) kit as a terminating action
to this AD.
We agree with the commenter. The replacement wing front lower spar
caps and other modification parts that are approved by STC SA03654AT,
Installation of Avenger Extended Performance Front Spar Enhancement Kit
(new wing front spar lower caps, center splice and doublers), in
accordance with Part II of Avenger Master Data List AAS-MDL-08-001,
Revision B, dated November 26, 2008, or later FAA-approved revision,
are a viable terminating action to this AD. The installation of STC
SA03654AT is an alternative to replacing the wing front lower spar caps
with Ayres/Thrush wing front lower spar caps.
We will change the final rule AD action to allow installing STC
SA03654AT as a terminating action for this AD.
Comment Issue No. 8: Require Reaming Bolt Hole Before Cold Working
Avenger states it is their opinion that the cold working process
accomplished as part of the Ayres Corporation Service Bulletin No. SB-
AG-39, dated September 17, 1996, is not being conducted correctly, and
fatigue damage is being introduced and made more critical than if cold
working was not accomplished at all. In order to utilize mandrel
expansion in a safe manner, the hole in question must first be reamed
to remove any corrosion or existing cracks that are too small to be
detected. This ``insurance cut'' is required to remove any anomaly in
the hole that may cause an issue during the cold working process.
Avenger requests the AD be amended to explicitly state that prior
to mandrel expansion, an insurance ream, capable of cleaning up a .03
inch undetected crack followed by a bolt hole eddy current inspection
using a calibration standard, be accomplished prior to the mandrel
expansion process.
We do not agree with the commenter. The AD already requires using
the cold working procedure found in Ayres Service Bulletin SB-AG-39,
dated September 17, 1996. Steps 7 and 8 in the Rework section of this
service bulletin require the bolt holes to be reamed before cold
working of the holes. These procedures must be accomplished in order to
be in compliance with this AD.
We are not changing the final rule AD based on this comment.
Comment Issue No. 9: Require Installing Big Butterfly Plates
Michael Morris and Mr. Brumley state that instead of mandating the
replacement of the wing lower spar caps, they would like the FAA to
require installing big butterfly plates. In addition to installing the
big butterfly plates, Mr. Morris also requests to keep the current
inspection intervals for magnetic particle and eddy current
inspections, and add a visual inspection every 100 hours TIS.
Mr. Morris states that he believes replacing the spar cap is
unnecessary for the following reasons:
The inspection program will continue to work;
The economic impact is too great; and
Some operators do not fly as aggressively as others and
should not be penalized for the actions of the other pilots.
We do not agree with the commenters. The ``big butterfly'' plate
does not have enough strength to carry all of the possible flight loads
in the event the wing spar cap is severed. This plate cannot be solely
relied upon to ensure the safety of the airplane.
Even if the spar cap is not completely severed but has a crack that
is large enough to see when performing the commenter's proposed 100-
hour TIS visual inspection, the remaining strength in the wing spar
joint is not enough to carry all of the possible flight loads. As
explained in the proposed AD, inspection reliability for any type of
inspection method is not 100 percent; therefore, over time the
probability of an inspection failing to detect a crack increases and
something more needs to be done to ensure the safety of the airplanes.
As shown in the Initial Regulatory Flexibility Analysis section of
the proposed AD, the economic impact was extensively studied. While we
agree the AD will have a significant economic impact on small
businesses, the only known way to ensure the safety of the airplane is
to replace the wing front lower spar caps.
We also agree that there are many variables affecting the life
limit of the wing front lower spar caps, including the operating
weights and operating G loads. Higher weights and higher G loads reduce
the life limit of the wing front lower spar caps. The only way to
consider giving credit to those who operate at lower weights and lower
G loads would be if each individual airplane had recorded data for
every flight since the wings were installed showing the weights and G
loads. Each individual airplane owner would then need to have fatigue
analysis and tests done by a qualified engineer to determine the life
limit for that particular set of wings based on that recorded data. The
expense of conducting this type of study for each airplane may be
higher than the cost of replacement wing front lower spar caps;
therefore, it may not be an economically viable alternative.
We are not changing the final rule AD action based on this comment.
Conclusion
We have carefully reviewed the available data and determined that
air safety and the public interest require adopting the AD as proposed
except for the changes previously discussed and minor editorial
corrections. We have determined that these minor corrections:
Are consistent with the intent that was proposed in the
NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.
Costs of Compliance
We estimate that this AD will affect 808 airplanes in the U.S.
registry, including those airplanes affected by AD 2006-07-15.
We estimate the following costs to do each inspection:
----------------------------------------------------------------------------------------------------------------
Total cost per Total cost on
Labor cost Parts cost airplane U.S. operators
----------------------------------------------------------------------------------------------------------------
3 work-hours x $80 = $240.................................... $525 $765 $618,120
----------------------------------------------------------------------------------------------------------------
[[Page 3131]]
We estimate the following costs to do cold work of bolt holes for
the repair that may be required based on the results of the inspection.
We have no way of determining the number of airplanes that may need
such repair:
------------------------------------------------------------------------
Total cost per
Labor cost Parts cost airplane
------------------------------------------------------------------------
1 work-hour x $80 = $80........... $100 $180
------------------------------------------------------------------------
We estimate the following costs to do any reaming of outer holes to
5/16-inch diameter for the repair that may be required based on the
results of the inspection. We have no way of determining the number of
airplanes that may need such repair:
------------------------------------------------------------------------
Total cost per
Labor cost Parts cost airplane
------------------------------------------------------------------------
1 work-hour x $80 = $80........ None................ $80
------------------------------------------------------------------------
We estimate the following costs to do any drilling and reaming of
outer holes and adding three holes to install a Kaplan splice block for
the repair that may be required based on the results of the inspection.
We have no way of determining the number of airplanes that may need
such modification:
------------------------------------------------------------------------
Total cost per
Labor cost Parts cost airplane
------------------------------------------------------------------------
65 work-hours x $80 = $5,200... $4,400 for splice $10,200
block and $600 for
hardware.
------------------------------------------------------------------------
We estimate the following costs to do any necessary wing front
lower spar cap replacement with the optional Ayres or Thrush part
numbers (P/Ns) 20207-1, 20207-2, 20207-11, 20207-12, 20207-13, 20207-
14, 20207-15, or 20207-16 that will be required based on the results of
the inspection or by the wing front lower spar cap reaching the life
limit:
------------------------------------------------------------------------
Parts cost per
Labor cost per wing front lower wing front Total cost per
spar cap lower spar cap airplane
------------------------------------------------------------------------
200 work-hours x $80 = $16,000. $8,000 Each spar cap
replacement = $24,000
Two wing front lower
spar caps per
airplane = $48,000.
------------------------------------------------------------------------
However, the supply of individual wing front lower spar caps (new
or used) is very limited.
We estimate the following costs to do the optional installation of
Thrush Aircraft, Inc. Custom Kit No. CK-AG-41, Revision A, dated March
8, 2007. This kit may be used to do any necessary wing front lower spar
cap replacements that will be required based on the results of the
inspection or that will be required based on reaching the life limit:
------------------------------------------------------------------------
Total cost per
Labor cost Parts cost airplane
------------------------------------------------------------------------
300 work-hours x $80 = $24,000.... $40,000 $64,000
------------------------------------------------------------------------
We estimate the following costs to do the optional installation of
Avenger Aircraft and Services STC SA03654AT for Avenger Extended
Performance Front Spar Enhancement Kit. This kit may be used to do any
necessary wing front lower spar cap replacements that will be required
based on the results of the inspection or that will be required based
on reaching the life limit:
------------------------------------------------------------------------
Total cost per
Labor cost Parts cost airplane
------------------------------------------------------------------------
319 work-hours x $80 = $25,520.... $40,000 $65,500
------------------------------------------------------------------------
The FAA estimates that 501 airplanes affected by this AD will
retire before their wing front lower spar cap life limits are reached.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, Section 106 describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the agency's authority.
[[Page 3132]]
We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this AD.
Final Regulatory Flexibility Analysis
Introduction and Purpose of This Analysis
The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA)
establishes ``as a principle of regulatory issuance that agencies shall
endeavor, consistent with the objectives of the rule and of applicable
statutes, to fit regulatory and informational requirements to the scale
of the businesses, organizations, and governmental jurisdictions
subject to regulation.'' To achieve this principle, the RFA requires
agencies to solicit and consider flexible regulatory proposals and to
explain the rationale for their actions to assure that such proposals
are seriously considered. The RFA covers a wide-range of small
entities, including small businesses, not-for-profit organizations, and
small governmental jurisdictions.
Agencies must perform a review to determine whether a rule will
have significant economic impact on a substantial number of small
entities. If the agency determines that it will, the agency must
prepare a regulatory flexibility analysis as described in the RFA.
We determined that this final rule will have a significant economic
impact on a substantial number of small entities and, accordingly, as
required by section 603(a) of the RFA, we prepared and published an
initial regulatory flexibility analysis (IRFA) as part of the NPRM for
this final rule (74 FR 20431, May 4, 2009). Section 604 of the RFA also
requires an agency to publish a final regulatory flexibility analysis
(FRFA) in the Federal Register when issuing a final rule. Section
604(a) requires that each FRFA contain:
A succinct statement of the need for, and objectives of,
the final rule;
A summary of the significant issues raised by the public
comments in response to the IRFA, a summary of agency's assessment of
such issues, and a statement of any changes made to the proposed final
rule resulting from such comments;
A description of the steps the agency has taken to
minimize the significant economic impact on small entities consistent
with the stated objectives of applicable statues, including a statement
of the factual, policy, and legal reasons for selecting the alternative
adopted in the final rule and why each one of the other significant
alternatives to the final rule considered by the agency that affect the
impact on small entities was rejected.
A description of and an estimate of the number of small
entities for which the final rule will apply; and
A description of the projected reporting, recordkeeping,
and other compliance requirements of the final rule, including an
estimate of the classes of small entities that will be subject to the
requirement and the type of professional skills necessary for
preparation of the report or record.
Need for, and Objectives of Final Rule
A series of ADs, beginning in 1997 and culminating in AD 2006-07-15
in 2006, addressed the issue of fatigue cracking of the wing front
lower spar caps in Thrush Aircraft, Inc. Model 600 S2D and S2R (S-2R)
series airplanes (type certificate previously held by Quality
Aerospace, Inc. and Ayres Corporation). This type of fatigue cracking,
if not addressed, could result in catastrophic wing failure. The
original 1997 AD was issued after an accident on an S2R series airplane
in which the wing separated from the airplane in flight. Requirements
of inspection and possible replacement were changed in 2000 to
repetitive inspections and possible replacement. In 2006, the
inspection rate was doubled after a completely severed wing front lower
spar cap was found on one of the affected airplanes and the FAA noted
that it was working with Thrush Aircraft, Inc. to develop a future
terminating action. Analysis indicated that an undetected crack had
existed during the previous two repetitive inspections of that wing
front lower spar cap.
Subsequent FAA analysis has shown that wing front lower spar cap
fatigue cracking has increased as the fleet has aged and will continue
to increase. Consequently, the incidences of undetected cracks will
increase, increasing the probability of catastrophic wing failure. The
FAA has concluded that repetitive inspections, as required since the
2000 AD, are insufficient by themselves to ensure the safety of these
airplanes and, accordingly, in this final rule the FAA is requiring
wing front lower spar cap life limits to address this safety issue.
Summary of Significant Issues Raised by the Public in Response to the
IRFA, Summary of FAA's Assessment of Such Issues, Statement of Changes
Made to the Final Rule as a Result of Such Issues, Description of the
Steps the Agency Has Taken To Minimize a Significant Economic Impact on
Small Entities, and Why Other Significant Alternatives to the Final
Rule That Affect Small Entities Were Rejected
There were no public comments to the IRFA, but there were public
comments to the proposed rule, which have relevance for small and large
entities alike.
As noted in the preamble to the final rule, Avenger commented that
it has developed a wing front lower spar replacement kit, which was not
available when the proposed rule was issued. The FAA has approved their
kit for a 40,000-hour TIS life limit. Avenger requested that the FAA
approve the installation of its kit as a terminating action to the AD.
As noted in the preamble, the FAA agrees with Avenger that installation
of its kit is a viable terminating action to this AD. Accordingly, it
is an alternative to replacing the wing front lower spar caps with
Ayres/Thrush spar caps; and the FAA has incorporated this change in the
final rule. This is a significant issue because the Ayres/Thrush kit,
although priced slightly lower than the Avenger kit, has a lower life
limit (ranging from 5,400 to 28,800 hours TIS.) Many of the affected
airplanes with the Ayres/Thrush kit installed will require multiple
replacements over their lifetimes and installation of the Ayres/Thrush
kit does not eliminate the requirement of repetitive inspections and
reporting requirements. Consequently, the estimated cost of the final
rule is lower given the availability of the Avenger kit as a
terminating action. In the cost analysis for the proposed rule, we
estimated the total cost to be $37.1 million. In the final rule, we
estimate total cost to be $20.1 million.\1\
---------------------------------------------------------------------------
\1\ Individual replacement of the two original equipment spars
is cheaper (for one installation) than installing the Ayres/Thrush
kit or the Avenger kit, but as noted in the ``Cost of Compliance''
section, the supply of these spar caps is very limited. Accordingly,
total cost is overestimated, but only slightly, by our assumption
that all operators would comply by installing a kit (NPRM: Ayres/
Thrush kit, final rule: Avenger kit).
---------------------------------------------------------------------------
As an alternative to replacing the wing front lower spar caps, two
commenters suggested that the FAA require installation of ``big
butterfly'' plates. But, as the FAA noted in the preamble, the ``big
butterfly plate'' does not have enough strength to carry all the
[[Page 3133]]
possible flight loads if the wing front lower spar caps were severed.
Accordingly, this plate cannot be solely relied upon to ensure the
safety of the airplane and is not an acceptable alternative method of
compliance to replacing the wing front lower spar caps.
Additionally, one commenter suggested 100-hour TIS visual
inspections. As discussed in the preamble, even if the wing front lower
spar cap is not completely severed, but has a crack that is large
enough to see when performing the 100-hour TIS visual inspection, the
remaining strength in the wing spar joint is not enough to carry all
possible flight loads. Therefore, the 100-hour TIS visual inspection
alone is not a sufficient alternative method of compliance.
The FAA believes there are currently no other available alternative
methods of compliance to the final rule that will allow the safety
objectives of the final rule to be achieved. The FAA, however, has
allowed a generous compliance period that will significantly reduce the
economic impact on small and large entities alike. As already noted in
the preamble, airplanes that have already exceeded the life limit on
their wing front lower spar caps are allowed 500, 1,000, 1,500, or
2,000 hours TIS to comply with the final rule, depending on the current
number of accumulated hours TIS. Since the average usage rate for the
affected airplanes is about 500 hours TIS per year, these allowances
are equivalent, on average, to 1, 2, 3, and 4 years to comply with the
final rule. Airplanes that have not yet reached their wing front lower
spar cap life limit are allowed a minimum of 2,000 hours TIS or, on
average, 4 years to comply with the final rule.
For a complete summary of public comments and the FAA's responses,
please see the Comments section in the preamble above.
A Description of and an Estimate of the Number of Small Entities for
Which the Final Rule Will Apply
This final rule will affect 808 U.S.-registered and -operated
Thrush Aircraft, Inc. Model 600S2D and S2R (S-2R) series airplanes. \2\
In conducting this analysis, the FAA reviewed data from the FAA
Registry to ascertain how many Thrush Aircraft, Inc. were registered
and operated by small entities. The FAA Registry indicates that these
808 airplanes are owned by 546 separate entities in agricultural
aviation. All but one of these entities are small entities as defined
by the Small Business Administration (SBA). Although the FAA Registry
does not record financial or business data about the registered owners
of aircraft, and such data for these entities are not readily available
elsewhere, it appears that most, if not all, of the 546 entities are
engaged in crop dusting, spraying, and seeding operations. These
activities are classified in North American Industry Classification
System (NAICS) industry, NAICS 115112--Soil Preparation, Planting, and
Cultivating (including Crop Dusting, Crop Spraying). The concentration
of these entities in a single NAICS industry reflects the specialized
nature of agricultural airplanes with restricted airworthiness
certificates. Furthermore, several of these entities were classified in
the Standard Industrial Classification (SIC) equivalent of NAICS 115112
by https://www.manta.com. Although a few of these entities may also be
engaged in firefighting, which is classified in NAICS 115310--Support
Activities for Forestry (including Forest Fire Suppression), the FAA is
unable to identify any of these entities as being principally engaged
in firefighting. The SBA small business classification for NAICS 115112
is a maximum of $6.5 million in business receipts, and for NAICS 115310
it is a maximum of $16.5 million in business receipts. Only one entity
in this sample appears to have business receipts over $6.5 million, and
no entity has business receipts in excess of $16.5 million. Using the
total number of airplanes owned as a size criterion, the FAA selected a
sample of 41 of the largest affected entities and found median sales
shown by https://www.manta.com to be just $250,000 annually. Firms in
agricultural aviation appear to be inherently of small size.
Accordingly, the FAA estimates that 545 small entities will be affected
by this final rule.
---------------------------------------------------------------------------
\2\ FAA Registry, https://www.faa.gov/licenses_certificates/aircraft_certification/aircraft_registry/releasable_aircraft_download/. Data downloaded on 4/14/08.
---------------------------------------------------------------------------
Reporting, Record Keeping, and Other Compliance Requirements
Small entities will incur no new reporting and record-keeping
requirements as a result of this final rule. In fact, such
requirements, for small and large firms alike, will be greatly reduced
since installation of the Avenger kit has been incorporated as an
alternative terminating action to this final rule.
This final rule will affect U.S. operators of Thrush Aircraft, Inc.
Model 600S2D and S2R (S-2R) series agricultural airplanes airplanes.
The affected airplanes were produced by Thrush Aircraft, Inc.
predecessor firms over the period 1965-2000. This final rule largely
retains the requirements of superseded AD 2006-07-15 to inspect/repair/
replace the currently installed Ayres/Thrush wing front lower spar
caps. The new requirements set life limits on the Ayres/Thrush wing
front lower spar caps and requires replacing of these wing front lower
spar caps when the life limits are reached.
Economic Impact on Small Entities
Replacing the wing front lower spar caps is expensive and,
consequently, as we show below, the final rule will have a significant
economic impact on the substantial number of small firms we identified
above.
The total compliance cost (undiscounted) is $65,520 for an affected
airplane for which the wing front lower spar caps are replaced before
retirement, or zero for an affected airplane that will retire before
its compliance date. Individual airplane compliance costs will result
in costs to the small entities that own these airplanes and will vary
depending on the number of affected airplanes owned by the entity. The
ownership table below shows the variation in the number of owners with
particular numbers of airplanes. The table shows that almost 75 percent
of the 546 individual owners have only one affected airplane, and more
than 90 percent of owners have no more than two affected airplanes. The
average (mean) number of affected airplanes held is 1.48, while the
median number held is just 1.00, so the median airplane cost is
equivalent to the median owner cost.
[[Page 3134]]
Number of Thrush Aircraft, Inc. Owners Having Particular Numbers of Affected Airplanes
----------------------------------------------------------------------------------------------------------------
Number of
affected
airplanes held Number of Cumulative %
by single owners
owner
----------------------------------------------------------------------------------------------------------------
1 406 74.4
2 86 90.1
3 26 94.9
4 13 97.3
5 7 98.5
6 2 98.9
7 2 99.3
8 1 99.5
9 2 99.8
13 1 100.0
Total........................................................... .............. 546 ..............
Mean............................................................ 1.48 .............. ..............
Median.......................................................... 1.00 .............. ..............
----------------------------------------------------------------------------------------------------------------
Source: FAA Registry. Data downloaded on 4/18/08.
In the ``Cost of Compliance'' section of this final rule, we
estimate total cost (undiscounted) to be $20.1 million and the present
value cost to be $18.2 million. As noted above, the FAA estimates that
545 of the 546 affected by this final rule are small firms, and, in
fact, 99.7 percent of the final rule's estimated cost is attributed to
small entities. The following document analyzes the impact of this cost
on the substantial number of small firms identified above.
Because the FAA Registry does not collect financial or business
data on these entities, and such data are not readily available
elsewhere, the FAA also used Census Bureau size distribution data to
assess the economic impact on small firms. The FAA used data from the
2002 Census since this is the latest census for which size distribution
by business receipts is readily available. These data are available in
a special census compilation for the SBA.\3\ The FAA used the data for
NAICS 115112--Soil Preparation, Planting, and Cultivating (including
Crop Dusting, Crop Spraying), but did not use the data for NAICS
115310--Support Activities for Forestry (including Forest Fire
Suppression) since, as noted above, a very high percentage of the
affected small firms, if not all, meet the classification standard of
NAICS 115112. Moreover, the size distribution of NAICS 115310 appears
to be similar to that of NAICS 115112. The concentration of the
affected airplanes in one NAICS industry, noted above, makes the use of
census data feasible and appropriate.
---------------------------------------------------------------------------
\3\ Small Business Administration, Office of Advocacy. https://www.sba.gov/advo/research/us_rec02.txt.
---------------------------------------------------------------------------
The relevant census data are provided in the table below:
2002 Census Data for NAICS 115112--Soil Preparation, Planting, and Cultivating (Incl. Crop Dusting, Crop Spraying)--Small Size Classes
--------------------------------------------------------------------------------------------------------------------------------------------------------
$0-100 $100-500 $500 thousand-
Measure Total thousand thousand 1 million $1-5 million $5-10 million
--------------------------------------------------------------------------------------------------------------------------------------------------------
Firms................................................... 2336 509 992 412 394 29
Percentage of firms..................................... .............. 21.8% 42.5% 17.6% 16.9% 1.2%
Upper bound percentile.................................. .............. 21.8% 64.3% 81.9% 98.8% 100.0%
Est. Receipts ($000).................................... $1,531,004 $25,681 $257,447 $286,462 $772,401 $189,013
Receipts/Firm ($)....................................... $655,396 $50,454 $259,523 $695,296 $1,960,409 $6,517,690
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: ``Firms'' and ``Est. Receipts'' from Small Business Administration, Office of Advocacy. https://www.sba.gov/advo/research/us_rec02.txt.
The table above shows the number of firms and business receipt data
for the five smallest size classes of NAICS 115112 that encompass the
size range of the firms affected by this final rule. In the
``Percentage of firms'' row, for each size class, the FAA calculates
that class's number of firms as a percentage of the total number of
firms in the five size classes. Cumulating this percentage from the
smallest to largest size class establishes the ``Upper bound
percentile''--the cumulated percentage of firms of business receipt
size ranging up to the upper bound of the size class. The final rule's
cost for the firms at the upper bound percentiles is then estimated as
the corresponding percentiles in the estimated firm-level compliance
cost data. In order to assess the economic impact of the final rule,
these costs are calculated as a percentage of the census data upper
bounds.
For example, the upper bound percentile for the $100-500 thousand
size class is 64.3 percent, so we estimate the NAICS 115112 firms at
that percentile to have business receipts of $500,000. As shown in the
table below, the FAA then determined the estimated compliance cost of
firms at the same percentile in the compliance cost data to be $57,584.
The FAA assumes these firms are the same, so the percentage cost impact
(AD Cost/Firm Size) is 11.5 percent. This procedure assumes the size
distribution of the 808 firms affected by the final rule has a
[[Page 3135]]
distribution similar to the overall distribution of the small firms in
NAICS 115112. It also assumes there is a perfect rank correlation
between the size of the affected firms and the firms' present value
compliance cost. While the latter assumption is certainly not the case,
any deviation from such perfect correlation can only increase the
impact of the final rule because smaller firms will have larger costs.
Accordingly, the FAA's determination that the final rule will have a
significant impact on a substantial number of small entities is
unaffected.
Economic Impact of AD on Small Firms
----------------------------------------------------------------------------------------------------------------
Estimated firm
size (Census Cumulative
AD cost to firm Firm percentile Bureau's AD cost/ number of
receipts upper firm size firms
bound)
----------------------------------------------------------------------------------------------------------------
$0....................................... 21.8 percentile............ $100,000 0.0% 119.2
$57,584.................................. 64.3 percentile............ $500,000 11.5% 351.5
$63,220.................................. 81.9 percentile............ $1,000,000 6.3% 447.9
$203,502................................. 98.8 percentile............ $5,000,000 4.1% 540.2
----------------------------------------------------------------------------------------------------------------
The table above shows a zero-cost impact on a firm at the 21.8
percentile. This result reflects the estimate in the FRFA cost analysis
(see docket) that more than 500 older airplanes will retire before
their wing front lower spar cap life limits are reached. As already
mentioned, the AD cost for a firm at the 64.3 percentile is $61,754,
which as a percentage of estimated firm size (size class upper bound)
is 11.5 percent of annual business receipts. This impact declines to
6.3 percent for a firm at the 81.9 percentile and to 4.1 percent for a
firm at the 98.8 percentile. The overall pattern is zero impact for the
smallest of the small firms owners of the oldest airplanes, but a
highly positive impact for the medium-sized small firms. In percentage
terms, this impact falls for the largest small firms, but remains at a
substantial level. While the FAA can make no definitive inference on
the impact of the final rule on firms between the 21.8 and 64.3
percentiles, the FAA notes the cost varies from 6.3 percent up to 11.5
percent of annual business receipts for 96 firms between the 81.9 and
64.3 percentiles and from 4.1 percent to 6.3 percent of annual business
receipts for 92 firms between the 98.8 and 81.9 percentiles. These
estimated percentage impacts are substantial. Therefore, the FAA
concludes that this final rule will have a significant impact on a
substantial number of small entities.
International Trade Impact Analysis
The Trade Agreement Act of 1979 prohibits Federal agencies from
establishing any standards or engaging in related activities that
create unnecessary obstacles to the foreign commerce of the United
States. The statute does not consider legitimate domestic objectives,
such as safety, as unnecessary. The statute also requires consideration
of international standards and, where appropriate, that they be the
basis for U.S. standards. The FAA is issuing this final rule because of
a known safety problem. Therefore, this final rule AD action applies
only to U.S. registered airplanes and is not considered an unnecessary
obstacle to international trade.
Unfunded Mandates Reform Act Assessment
Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement
assessing the effects of any Federal mandate in a proposed or final
agency rule that may result in an expenditure of $100 million or more
(adjusted annually for inflation with the base year 1995) in any one
year by State, local, and Tribal governments in the aggregate, or by
the private sector. The Act deems such a mandate to be a ``significant
regulatory action.'' The FAA currently uses an inflation-adjusted value
of $136.1 million. This rule does not contain such a mandate.
Regulatory Findings
We have determined that this AD will not have federalism
implications under Executive Order 13132. This AD will not have a
substantial direct effect on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.
For the reasons discussed above, I certify that this AD:
1. Is not a ``significant regulatory action'' under Executive Order
12866;
2. Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979); and
3. Will have a significant economic impact, positive or negative,
on a substantial number of small entities under the criteria of the
Regulatory Flexibility Act.
We prepared a summary of the costs to comply with this AD (and
other information as included in the Regulatory Evaluation) and placed
it in the AD Docket. You may get a copy of this summary by sending a
request to us at the address listed under ADDRESSES. Include ``Docket
No. FAA-2007-27862; Directorate Identifier 2007-CE-036-AD'' in your
request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
0
Accordingly, under the authority delegated to me by the Administrator,
the Federal Aviation Administration amends part 39 of the Federal
Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD)
2006-07-15, Amendment 39-14542 (71 FR 16691, April 4, 2006), and adding
the following new AD:
2009-26-11 Thrush Aircraft, Inc. (Type Certificate Previously Held
by Quality Aerospace, Inc. and Ayres Corporation): Amendment 39-
16150; Docket No. FAA-2007-27862; Directorate Identifier 2007-CE-
036-AD.
Effective Date
(a) This AD becomes effective on February 24, 2010.
Affected ADs
(b) The following lists a history of the ADs affected by this AD
action:
(1) This AD supersedes AD 2006-07-15, Amendment 39-14542;
[[Page 3136]]
(2) AD 2006-07-15 superseded AD 2003-07-01, Amendment 39-13097;
(3) AD 2003-07-01 superseded AD 2000-11-16, Amendment 39-11764;
(4) AD 2000-11-16 superseded AD 97-17-03, Amendment 39-10195;
and
(5) AD 97-17-03 superseded AD 97-13-11, Amendment 39-10071.
Applicability
(c) This AD affects the following airplane models and serial
numbers (S/Ns) in Table 1 that are certificated in any category when
wing front lower spar cap part numbers (P/Ns) 20207-1, 20207-2,
20207-11, 20207-12, 20207-13, 20207-14, 20207-15, or 20207-16 are
installed. This AD applies to the S/Ns in Table 1 with or without a
``DC'' suffix. This AD does not affect airplanes with any other wing
front lower spar cap part number, e.g. Thrush P/N 22507 (any dash
number) or Supplemental Type Certificate (STC) SA03654AT parts. The
table also identifies the group that each airplane belongs in when
determining inspection compliance times and life limit times for the
parts:
Table 1--Applicability and Airplane Groups
------------------------------------------------------------------------
Model S/Ns Group
------------------------------------------------------------------------
(1) S-2R.......................... 5000R through 5100R, 1
except 5010R, 5031R,
5038R, 5047R, and 5085R.
(2) S2R-G1........................ G1-101 through G1-106..... 1
(3) S2R-R1820..................... R1820-001 through R1820- 1
035.
(4) S2R-T15....................... T15-001 through T15-033 1
(also see paragraph (d)
of this AD).
(5) S2R-T34....................... 6000R through 6049R, T34- 1
001 through.
T34-143, T34-145, T34-171,
T34[dash]180, and.
T34-181 (also see
paragraph (e) of this AD).
(6) S2R-G10....................... G10-101 through G10-138, 2
G10-140, and.
G10-141...................
(7) S2R-G5........................ G5-101 through G5-105..... 2
(8) S2R-G6........................ G6-101 through G6-147..... 2
(9) S2RHG-T65..................... T65-002 through T65-018... 2
(10) S2R-R1820.................... R1820-036................. 2
(11) S2R-T34...................... T34-144, T34-146 through 2
T34-170, T34-172 through
T34-179, and T34-189
through T34-234 (also see
paragraph (e) of this AD).
(12) S2R-T45...................... T45-001 through T45-014... 2
(13) S2R-T65...................... T65-001 through T65-018... 2
(14) 600 S2D...................... All serial numbers 3
beginning with 600-1311D.
(15) S-2R......................... 1380R, 1416R through 3
2592R, 3000R, and 3002R.
(16) S2R-R1340.................... R1340-001 through R1340- 3
035.
(17) S2R-R3S...................... R3S-001 through R3S-011... 3
(18) S2R-T11...................... T11-001 through T11-005... 3
(19) S2R-G1....................... G1-107 through G1-115..... 5
(20) S2R-G10...................... G10-139, G10-142 through 5
G10-165.
(21) S2R-G6....................... G6-148 through G6-155..... 5
(22) S2RHG-T34.................... T34HG-102................. 5
(23) S2R-T15...................... T15-034 through T15-040 5
(also see paragraph (d)
of this AD).
(24) S2R-T34...................... T34-236 through T34-270 5
(also see paragraph (e)
of this AD).
(25) S2R-T45...................... T45-015................... 5
(26) S-2R......................... 5010R, 5031R, 5038R, 6
5047R, and 5085R.
------------------------------------------------------------------------
(d) The S/Ns of Model S2R-T15 airplanes could incorporate T15-
xxx and T27-xxx (xxx is the variable for any of the S/Ns beginning
with T15- and T27-). This AD applies to both of these S/N
designations as they are both Model S2R-T15 airplanes.
(e) The S/Ns of Model S2R-T34 airplanes could incorporate T34-
xxx, T36-xxx, T41-xxx, or T42-xxx (xxx is the variable for any of
the S/Ns beginning with T34-, T36-, T41-, and T42-). This AD applies
to all of these S/N designations as they are all Model S2R-T34
airplanes.
(f) Any Group 3 airplane that has been modified with a hopper of
a capacity more than 410 gallons, a piston engine greater than 600
horsepower, or a gas turbine engine greater than 600 horsepower, is
a Group 1 airplane for the purposes of this AD. Inspect the airplane
at the Group 1 compliance time specified in this AD. Replace the
wing front lower spar caps in accordance with the formulas given in
paragraph (k) of this AD.
(g) Group 6 airplanes were originally manufactured with higher
horsepower radial engines, but were converted to lower horsepower
radial engines.
