Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800 and -900 Series Airplanes, 29280-29282 [E7-10137]
Download as PDF
29280
Federal Register / Vol. 72, No. 101 / Friday, May 25, 2007 / Proposed Rules
Issued in Renton, Washington, on May 17,
2007.
Ali Bahrami,
Manager, Transport Airplane Directorate,
Aircraft Certification Service.
[FR Doc. E7–10138 Filed 5–24–07; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2007–28283; Directorate
Identifier 2006–NM–254–AD]
RIN 2120–AA64
Airworthiness Directives; Boeing
Model 737–600, –700, –700C, –800 and
–900 Series Airplanes
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking
(NPRM).
cprice-sewell on PROD1PC71 with PROPOSALS
AGENCY:
SUMMARY: The FAA proposes to adopt a
new airworthiness directive (AD) for
certain Boeing Model 737–600, –700,
–700C, –800 and –900 series airplanes.
This proposed AD would require a onetime general visual inspection of frames
between body station (BS) 360 and BS
907 to determine if certain support
brackets of the air conditioning (A/C)
outlet extrusions are installed; mediumand high-frequency eddy current
inspections for cracking of the frames
around the attachment holes of the
subject brackets; and repair if necessary.
This proposed AD would also require
installing new, improved fittings for all
support brackets of the A/C outlet
extrusions between BS 360 and BS 907.
This proposed AD results from
numerous reports of multiple cracks in
the frames around the attachment holes
of certain support brackets of the A/C
outlet extrusions. We are proposing this
AD to detect and correct frame cracking,
which, if not corrected, could lead to a
severed frame that, combined with
cracking of the skin lap splice above
stringer 10, could result in rapid
decompression of the airplane.
DATES: We must receive comments on
this proposed AD by July 9, 2007.
ADDRESSES: Use one of the following
addresses to submit comments on this
proposed AD.
• DOT Docket Web site: Go to
https://dms.dot.gov and follow the
instructions for sending your comments
electronically.
• Government-wide rulemaking Web
site: Go to https://www.regulations.gov
VerDate Aug<31>2005
15:35 May 24, 2007
Jkt 211001
and follow the instructions for sending
your comments electronically.
• Mail: Docket Management Facility,
U.S. Department of Transportation, 400
Seventh Street, SW., Nassif Building,
Room PL–401, Washington, DC 20590.
• Fax: (202) 493–2251.
• Hand Delivery: Room PL–401 on
the plaza level of the Nassif Building,
400 Seventh Street, SW., Washington,
DC, between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
Contact Boeing Commercial
Airplanes, P.O. Box 3707, Seattle,
Washington 98124–2207, for the service
information identified in this proposed
AD.
FOR FURTHER INFORMATION CONTACT:
Wayne Lockett, Aerospace Engineer,
Airframe Branch, ANM–120S, FAA,
Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton,
Washington 98057–3356; telephone
(425) 917–6447; fax (425) 917–6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to submit any relevant
written data, views, or arguments
regarding this proposed AD. Send your
comments to an address listed in the
ADDRESSES section. Include the docket
number ‘‘FAA–2007–28283; Directorate
Identifier 2006–NM–254–AD’’ at the
beginning of your comments. We
specifically invite comments on the
overall regulatory, economic,
environmental, and energy aspects of
the proposed AD. We will consider all
comments received by the closing date
and may amend the proposed AD in
light of those comments.
We will post all comments we
receive, without change, to https://
dms.dot.gov, including any personal
information you provide. We will also
post a report summarizing each
substantive verbal contact with FAA
personnel concerning this proposed AD.
Using the search function of that Web
site, anyone can find and read the
comments in any of our dockets,
including the name of the individual
who sent the comment (or signed the
comment on behalf of an association,
business, labor union, etc.). You may
review DOT’s complete Privacy Act
Statement in the Federal Register
published on April 11, 2000 (65 FR
19477–78), or you may visit https://
dms.dot.gov.
Examining the Docket
You may examine the AD docket on
the Internet at https://dms.dot.gov, or in
person at the Docket Management
Facility office between 9 a.m. and 5
p.m., Monday through Friday, except
PO 00000
Frm 00003
Fmt 4702
Sfmt 4702
Federal holidays. The Docket
Management Facility office (telephone
(800) 647–5227) is located on the plaza
level of the Nassif Building at the DOT
street address stated in the ADDRESSES
section. Comments will be available in
the AD docket shortly after the Docket
Management System receives them.
Discussion
We have received numerous reports of
multiple cracks in the frame around the
attachment holes of certain support
brackets of the air conditioning (A/C)
outlet extrusions on Model 737–200,
–300, –400, and –500 series airplanes.
Investigation has revealed that the frame
cracks occur due to fatigue caused by a
combination of forward and aft loads
from fuselage expansion, and down
loads from fuselage deflection on the
attached structure. The subject frame
cracks radiate from one side of the
attachment hole, nearest the frame
flanges; further, frame cracks up to 0.6
inch long have also been found on the
inboard flange of the body station (BS)
907 frame adjacent to the support
bracket. With continued fatigue cycling,
frame cracking, if not corrected, could
lead to a severed frame that, combined
with cracking of the skin lap splice
above stringer 10, could result in rapid
decompression of the airplane.
The subject area on Model 737–600,
–700, –700C, –800 and –900 series
airplanes is almost identical to that on
the affected Model 737–200, –300, –400,
and –500 series airplanes. Therefore,
certain Model 737–600, –700, –700C,
–800 and –900 series airplanes are
subject to the unsafe condition revealed
on the Model 737–200, –300, –400, and
–500 series airplanes.
The inspection threshold specified for
the Model 737–600, –700, –700C, –900,
and –900 series airplanes is later than
the total flight cycles accumulated by
some Model 737–200, –300, –400, and
–500 series airplanes with reported
cracks. We have determined that this is
acceptable based on growth rate and
cracking pattern of the cracks.
Relevant Service Information
We have reviewed Boeing Special
Attention Service Bulletin 737–25–
1544, dated October 4, 2006. The service
bulletin describes procedures for doing
a general visual inspection (GVI) of the
frames between BS 360 and BS 907 to
identify support brackets of the A/C
outlet extrusions that have a two-rivet
attachment fitting. The service bulletin
also describes procedures for doing
medium- and high-frequency eddy
current (MFEC and HFEC) inspections
for cracking of the frames around the
attachment holes of the identified
E:\FR\FM\25MYP1.SGM
25MYP1
29281
Federal Register / Vol. 72, No. 101 / Friday, May 25, 2007 / Proposed Rules
support brackets. The service bulletin
also describes frame repair, if necessary,
which includes installing reinforcing
repair angles. The service bulletin also
describes procedures for installing new,
improved support fittings for all A/C
outlet extrusions between BS 360 and
BS 907. Accomplishing the actions
specified in the service information is
intended to adequately address the
unsafe condition.
FAA’s Determination and Requirements
of the Proposed AD
We have evaluated all pertinent
information and identified an unsafe
condition that is likely to exist or
develop on other airplanes of this same
type design. For this reason, we are
proposing this AD, which would require
accomplishing the actions specified in
the service information described
previously.
Clarification of Purpose of GVI
Operators should note that, although
the service bulletin indicates that the
GVI is part of the procedure to detect
cracking in the areas previously
described, the primary intent of the GVI
is to determine which support brackets
between BS 360 and BS 907 are attached
to the airframe with two rivets. Only
those support brackets are subject to the
inspections for cracking specified by the
service bulletin. Therefore, this
proposed AD would require a GVI to
identify those support brackets between
BS 360 and BS 907 that are attached to
the airframe with two rivets.
Related Rulemaking
This unsafe condition may also exist
in Boeing Model 737–200, –300, –400,
and –500 series airplanes. Therefore, we
have issued AD 2006–26–09,
Amendment 39–14867 (72 FR 252,
January 4, 2007), which has similar
requirements, to address the unsafe
condition in those airplane models.
That unsafe condition, if uncorrected,
could result in a severed frame that,
combined with existing multi-site
damage at the stringer 10 lap splice,
could result in rapid decompression of
the airplane.
Costs of Compliance
There are about 1,679 airplanes of the
affected design in the worldwide fleet.
This proposed AD would affect about
626 airplanes of U.S. registry. The
following table provides the estimated
costs for U.S. operators to comply with
this proposed AD, at an average labor
rate of $80 per work hour. Operators
should note that special cold working
tools and sleeves will be needed if any
repair is required, which may increase
costs.
ESTIMATED COSTS
Action
Work hours
Parts
Cost per airplane
General visual inspection ..
MFEC and HFEC inspections.
Replace support fittings .....
1 ........................................
Between 170 and 216 .......
No parts required ..............
No parts required ..............
Between 258 and 346 .......
Between $56,095 and
$81,339.
$80 ....................................
Between $13,600 and
$17,280.
Between $76,735 and
$109,019.
Authority for This Rulemaking
cprice-sewell on PROD1PC71 with PROPOSALS
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.
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 rulemaking
action.
Regulatory Findings
We have determined that this
proposed AD would not have federalism
implications under Executive Order
13132. This proposed AD would not
have a substantial direct effect on the
States, on the relationship between the
national Government and the States, or
VerDate Aug<31>2005
15:35 May 24, 2007
Jkt 211001
on the distribution of power and
responsibilities among the various
levels of government.
For the reasons discussed above, I
certify that the proposed regulation:
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 not 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 regulatory evaluation
of the estimated costs to comply with
this proposed AD and placed it in the
AD docket. See the ADDRESSES section
for a location to examine the regulatory
evaluation.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation
safety, Safety.
The Proposed Amendment
Accordingly, under the authority
delegated to me by the Administrator,
the FAA proposes to amend 14 CFR part
39 as follows:
PO 00000
Frm 00004
Fmt 4702
Sfmt 4702
Fleet cost
$50,080.
Up to $10,817,280.
Up to $68,245,894.
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 Federal Aviation
Administration (FAA) amends § 39.13
by adding the following new
airworthiness directive (AD):
Boeing: Docket No. FAA–2007–28283;
Directorate Identifier 2006–NM–254–AD.
Comments Due Date
(a) The FAA must receive comments on
this AD action by July 9, 2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737–
600, –700, –700C, –800 and –900 series
airplanes; certificated in any category; as
identified in Boeing Special Attention
Service Bulletin 737–25–1544, dated October
4, 2006.
Unsafe Condition
(d) This AD results from numerous reports
of multiple cracks in the frame around the
attachment holes of the support bracket of
the air conditioning (A/C) outlet extrusion.
We are issuing this AD to detect and correct
E:\FR\FM\25MYP1.SGM
25MYP1
29282
Federal Register / Vol. 72, No. 101 / Friday, May 25, 2007 / Proposed Rules
frame cracking, which, if not corrected, could
lead to a severed frame that, combined with
cracking of the skin lap splice above stringer
10, could result in rapid decompression of
the airplane.
Compliance
(e) You are responsible for having the
actions required by this AD performed within
the compliance times specified, unless the
actions have already been done.
Service Bulletin Reference
(f) The term ‘‘service bulletin,’’ as used in
this AD, means Boeing Special Attention
Service Bulletin 737–25–1544, dated October
4, 2006.
Inspections
(g) Before the accumulation of 36,000 total
flight cycles, or within 72 months after the
effective date of this AD, whichever occurs
later: Do a general visual inspection to
determine if the support bracket of any A/C
outlet extrusion between body station (BS)
360 and BS 907 has a two-rivet attachment
fitting, then do the actions described by
paragraph (g)(1) and (g)(2) of this AD; in
accordance with part 2 of the
accomplishment instructions of the service
bulletin.
(1) For any subject support bracket not
attached with a two-rivet attachment fitting,
no further action is required by paragraph (g)
of this AD.
(2) For any subject support bracket having
a two-rivet attachment fitting, do mediumand high-frequency eddy current inspections
for cracking of the frame around the
attachment holes of the support bracket. If
any cracking is discovered, before further
flight, repair the cracking in accordance with
part 3 of the accomplishment instructions of
the service bulletin.
cprice-sewell on PROD1PC71 with PROPOSALS
Modification
(h) Before the accumulation of 36,000 total
flight cycles, or within 72 months after the
effective date of this AD, whichever occurs
later, replace the support fittings of all A/C
outlet extrusions between BS 360 and BS 907
with new, improved support fittings, in
accordance with part 4 of the
accomplishment instructions of the service
bulletin.
Alternative Methods of Compliance
(AMOCs)
(i)(1) The Manager, Seattle Aircraft
Certification Office (ACO), FAA, has the
authority to approve AMOCs for this AD, if
requested in accordance with the procedures
found in 14 CFR 39.19.
(2) To request a different method of
compliance or a different compliance time
for this AD, follow the procedures 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.
(3) An AMOC that provides an acceptable
level of safety may be used for any repair
required by this AD, if it is approved by an
Authorized Representative for the Boeing
Commercial Airplanes Delegation Option
VerDate Aug<31>2005
15:35 May 24, 2007
Jkt 211001
Authorization Organization who has been
authorized by the Manager, Seattle ACO, to
make those findings. For a repair method to
be approved, the repair must meet the
certification basis of the airplane, and the
approval must specifically refer to this AD.
Issued in Renton, Washington, on May 15,
2007.
Ali Bahrami,
Manager, Transport Airplane Directorate,
Aircraft Certification Service.
[FR Doc. E7–10137 Filed 5–24–07; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2007–28281; Directorate
Identifier 2006–NM–238–AD]
Comments Invited
RIN 2120–AA64
Airworthiness Directives; Boeing
Model 767 Airplanes
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking
(NPRM).
AGENCY:
SUMMARY: The FAA proposes to adopt a
new airworthiness directive (AD) for all
Boeing Model 767 airplanes. This
proposed AD would require repetitive
replacement of the internal electrical
feed-through connectors of the main
fuel tank boost pumps. This proposed
AD results from a report of cracking in
the epoxy potting compound on the
internal feed-through connector of the
fuel boost pump in the area of the
soldered wire connector lugs. We are
proposing this AD to prevent a
hazardous electrical path from the dry
side to the wet side of the fuel boost
pump through a cracked feed-through
connector, which could create an
ignition source on the wet side of the
fuel boost pump and lead to subsequent
explosion of the fuel tank.
DATES: We must receive comments on
this proposed AD by July 9, 2007.
ADDRESSES: Use one of the following
addresses to submit comments on this
proposed AD.
• DOT Docket Web site: Go to
https://dms.dot.gov and follow the
instructions for sending your comments
electronically.
• Government-wide rulemaking Web
site: Go to https://www.regulations.gov
and follow the instructions for sending
your comments electronically.
• Mail: Docket Management Facility,
U.S. Department of Transportation, 400
PO 00000
Frm 00005
Fmt 4702
Seventh Street, SW., Nassif Building,
Room PL–401, Washington, DC 20590.
• Fax: (202) 493–2251.
• Hand Delivery: Room PL–401 on
the plaza level of the Nassif Building,
400 Seventh Street, SW., Washington,
DC, between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
Contact Boeing Commercial
Airplanes, P.O. Box 3707, Seattle,
Washington 98124–2207, for the service
information identified in this proposed
AD.
FOR FURTHER INFORMATION CONTACT: Judy
Coyle, Aerospace Engineer, Propulsion
Branch, ANM–140S, FAA, Seattle
Aircraft Certification Office, 1601 Lind
Avenue, SW., Renton, Washington
98057–3356; telephone (425) 917–6497;
fax (425) 917–6590.
SUPPLEMENTARY INFORMATION:
Sfmt 4702
We invite you to submit any relevant
written data, views, or arguments
regarding this proposed AD. Send your
comments to an address listed in the
ADDRESSES section. Include the docket
number ‘‘FAA–2007–28281; Directorate
Identifier 2006–NM–238–AD’’ at the
beginning of your comments. We
specifically invite comments on the
overall regulatory, economic,
environmental, and energy aspects of
the proposed AD. We will consider all
comments received by the closing date
and may amend the proposed AD in
light of those comments.
We will post all comments we
receive, without change, to https://
dms.dot.gov, including any personal
information you provide. We will also
post a report summarizing each
substantive verbal contact with FAA
personnel concerning this proposed AD.
Using the search function of that web
site, anyone can find and read the
comments in any of our dockets,
including the name of the individual
who sent the comment (or signed the
comment on behalf of an association,
business, labor union, etc.). You may
review DOT’s complete Privacy Act
Statement in the Federal Register
published on April 11, 2000 (65 FR
19477–78), or you may visit https://
dms.dot.gov.
Examining the Docket
You may examine the AD docket on
the Internet at https://dms.dot.gov, or in
person at the Docket Management
Facility office between 9 a.m. and 5
p.m., Monday through Friday, except
Federal holidays. The Docket
Management Facility office (telephone
(800) 647–5227) is located on the plaza
level of the Nassif Building at the DOT
E:\FR\FM\25MYP1.SGM
25MYP1
Agencies
[Federal Register Volume 72, Number 101 (Friday, May 25, 2007)]
[Proposed Rules]
[Pages 29280-29282]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-10137]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-28283; Directorate Identifier 2006-NM-254-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800
and -900 Series Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Boeing Model 737-600, -700, -700C, -800 and -900 series
airplanes. This proposed AD would require a one-time general visual
inspection of frames between body station (BS) 360 and BS 907 to
determine if certain support brackets of the air conditioning (A/C)
outlet extrusions are installed; medium- and high-frequency eddy
current inspections for cracking of the frames around the attachment
holes of the subject brackets; and repair if necessary. This proposed
AD would also require installing new, improved fittings for all support
brackets of the A/C outlet extrusions between BS 360 and BS 907. This
proposed AD results from numerous reports of multiple cracks in the
frames around the attachment holes of certain support brackets of the
A/C outlet extrusions. We are proposing this AD to detect and correct
frame cracking, which, if not corrected, could lead to a severed frame
that, combined with cracking of the skin lap splice above stringer 10,
could result in rapid decompression of the airplane.
DATES: We must receive comments on this proposed AD by July 9, 2007.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed AD.
DOT Docket Web site: Go to https://dms.dot.gov and follow
the instructions for sending your comments electronically.
Government-wide rulemaking Web site: Go to https://
www.regulations.gov and follow the instructions for sending your
comments electronically.
Mail: Docket Management Facility, U.S. Department of
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401,
Washington, DC 20590.
Fax: (202) 493-2251.
Hand Delivery: Room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207, for the service information identified in this
proposed AD.
FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6447; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to submit any relevant written data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
28283; Directorate Identifier 2006-NM-254-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of the proposed AD. We will
consider all comments received by the closing date and may amend the
proposed AD in light of those comments.
We will post all comments we receive, without change, to https://
dms.dot.gov, including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA
personnel concerning this proposed AD. Using the search function of
that Web site, anyone can find and read the comments in any of our
dockets, including the name of the individual who sent the comment (or
signed the comment on behalf of an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
may visit https://dms.dot.gov.
Examining the Docket
You may examine the AD docket on the Internet at https://
dms.dot.gov, or in person at the Docket Management Facility office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT
street address stated in the ADDRESSES section. Comments will be
available in the AD docket shortly after the Docket Management System
receives them.
Discussion
We have received numerous reports of multiple cracks in the frame
around the attachment holes of certain support brackets of the air
conditioning (A/C) outlet extrusions on Model 737-200, -300, -400, and
-500 series airplanes. Investigation has revealed that the frame cracks
occur due to fatigue caused by a combination of forward and aft loads
from fuselage expansion, and down loads from fuselage deflection on the
attached structure. The subject frame cracks radiate from one side of
the attachment hole, nearest the frame flanges; further, frame cracks
up to 0.6 inch long have also been found on the inboard flange of the
body station (BS) 907 frame adjacent to the support bracket. With
continued fatigue cycling, frame cracking, if not corrected, could lead
to a severed frame that, combined with cracking of the skin lap splice
above stringer 10, could result in rapid decompression of the airplane.
The subject area on Model 737-600, -700, -700C, -800 and -900
series airplanes is almost identical to that on the affected Model 737-
200, -300, -400, and -500 series airplanes. Therefore, certain Model
737-600, -700, -700C, -800 and -900 series airplanes are subject to the
unsafe condition revealed on the Model 737-200, -300, -400, and -500
series airplanes.
The inspection threshold specified for the Model 737-600, -700, -
700C, -900, and -900 series airplanes is later than the total flight
cycles accumulated by some Model 737-200, -300, -400, and -500 series
airplanes with reported cracks. We have determined that this is
acceptable based on growth rate and cracking pattern of the cracks.
Relevant Service Information
We have reviewed Boeing Special Attention Service Bulletin 737-25-
1544, dated October 4, 2006. The service bulletin describes procedures
for doing a general visual inspection (GVI) of the frames between BS
360 and BS 907 to identify support brackets of the A/C outlet
extrusions that have a two-rivet attachment fitting. The service
bulletin also describes procedures for doing medium- and high-frequency
eddy current (MFEC and HFEC) inspections for cracking of the frames
around the attachment holes of the identified
[[Page 29281]]
support brackets. The service bulletin also describes frame repair, if
necessary, which includes installing reinforcing repair angles. The
service bulletin also describes procedures for installing new, improved
support fittings for all A/C outlet extrusions between BS 360 and BS
907. Accomplishing the actions specified in the service information is
intended to adequately address the unsafe condition.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other airplanes
of this same type design. For this reason, we are proposing this AD,
which would require accomplishing the actions specified in the service
information described previously.
Clarification of Purpose of GVI
Operators should note that, although the service bulletin indicates
that the GVI is part of the procedure to detect cracking in the areas
previously described, the primary intent of the GVI is to determine
which support brackets between BS 360 and BS 907 are attached to the
airframe with two rivets. Only those support brackets are subject to
the inspections for cracking specified by the service bulletin.
Therefore, this proposed AD would require a GVI to identify those
support brackets between BS 360 and BS 907 that are attached to the
airframe with two rivets.
Related Rulemaking
This unsafe condition may also exist in Boeing Model 737-200, -300,
-400, and -500 series airplanes. Therefore, we have issued AD 2006-26-
09, Amendment 39-14867 (72 FR 252, January 4, 2007), which has similar
requirements, to address the unsafe condition in those airplane models.
That unsafe condition, if uncorrected, could result in a severed frame
that, combined with existing multi-site damage at the stringer 10 lap
splice, could result in rapid decompression of the airplane.
Costs of Compliance
There are about 1,679 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 626 airplanes of
U.S. registry. The following table provides the estimated costs for
U.S. operators to comply with this proposed AD, at an average labor
rate of $80 per work hour. Operators should note that special cold
working tools and sleeves will be needed if any repair is required,
which may increase costs.
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Action Work hours Parts Cost per airplane Fleet cost
----------------------------------------------------------------------------------------------------------------
General visual inspection....... 1................. No parts required. $80............... $50,080.
MFEC and HFEC inspections....... Between 170 and No parts required. Between $13,600 Up to $10,817,280.
216. and $17,280.
Replace support fittings........ Between 258 and Between $56,095 Between $76,735 Up to $68,245,894.
346. and $81,339. and $109,019.
----------------------------------------------------------------------------------------------------------------
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.
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
rulemaking action.
Regulatory Findings
We have determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 the proposed
regulation:
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 not 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 regulatory evaluation of the estimated costs to
comply with this proposed AD and placed it in the AD docket. See the
ADDRESSES section for a location to examine the regulatory evaluation.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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.
Sec. 39.13 [Amended]
2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by
adding the following new airworthiness directive (AD):
Boeing: Docket No. FAA-2007-28283; Directorate Identifier 2006-NM-
254-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by July 9,
2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-600, -700, -700C, -800
and -900 series airplanes; certificated in any category; as
identified in Boeing Special Attention Service Bulletin 737-25-1544,
dated October 4, 2006.
Unsafe Condition
(d) This AD results from numerous reports of multiple cracks in
the frame around the attachment holes of the support bracket of the
air conditioning (A/C) outlet extrusion. We are issuing this AD to
detect and correct
[[Page 29282]]
frame cracking, which, if not corrected, could lead to a severed
frame that, combined with cracking of the skin lap splice above
stringer 10, could result in rapid decompression of the airplane.
Compliance
(e) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.
Service Bulletin Reference
(f) The term ``service bulletin,'' as used in this AD, means
Boeing Special Attention Service Bulletin 737-25-1544, dated October
4, 2006.
Inspections
(g) Before the accumulation of 36,000 total flight cycles, or
within 72 months after the effective date of this AD, whichever
occurs later: Do a general visual inspection to determine if the
support bracket of any A/C outlet extrusion between body station
(BS) 360 and BS 907 has a two-rivet attachment fitting, then do the
actions described by paragraph (g)(1) and (g)(2) of this AD; in
accordance with part 2 of the accomplishment instructions of the
service bulletin.
(1) For any subject support bracket not attached with a two-
rivet attachment fitting, no further action is required by paragraph
(g) of this AD.
(2) For any subject support bracket having a two-rivet
attachment fitting, do medium- and high-frequency eddy current
inspections for cracking of the frame around the attachment holes of
the support bracket. If any cracking is discovered, before further
flight, repair the cracking in accordance with part 3 of the
accomplishment instructions of the service bulletin.
Modification
(h) Before the accumulation of 36,000 total flight cycles, or
within 72 months after the effective date of this AD, whichever
occurs later, replace the support fittings of all A/C outlet
extrusions between BS 360 and BS 907 with new, improved support
fittings, in accordance with part 4 of the accomplishment
instructions of the service bulletin.
Alternative Methods of Compliance (AMOCs)
(i)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, has the authority to approve AMOCs for this AD, if requested in
accordance with the procedures found in 14 CFR 39.19.
(2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures 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.
(3) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD, if it is approved by an
Authorized Representative for the Boeing Commercial Airplanes
Delegation Option Authorization Organization who has been authorized
by the Manager, Seattle ACO, to make those findings. For a repair
method to be approved, the repair must meet the certification basis
of the airplane, and the approval must specifically refer to this
AD.
Issued in Renton, Washington, on May 15, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-10137 Filed 5-24-07; 8:45 am]
BILLING CODE 4910-13-P