Airworthiness Directives; Boeing Model 747 Airplanes, 54751-54755 [E8-22215]
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Federal Register / Vol. 73, No. 185 / Tuesday, September 23, 2008 / Proposed Rules
(NPA) 2002–043. The identified noncompliances were assessed using Transport
Canada Policy Letter No. 525–001 to
determine if mandatory corrective action was
required.
The assessment showed that due to the
close proximity of intrinsically safe fuel
system wiring with other wiring, a single
failure from wire chafing at various locations
of the fuselage could result in an ignition
source inside the fuel tank. In addition,
chafing of the temperature sensor wiring
against the high power wiring in the avionics
compartment could lead to overheating of the
temperature sensor and hot surface ignition.
The presence of an ignition source inside the
fuel tank could result in a fuel tank
explosion.
To correct the unsafe condition, this
directive mandates the installation of conduit
and the addition of spacers to protect fuel
tank wiring.
Actions and Compliance
(f) Unless already done, do the following
actions.
(1) Within 4,500 flight hours after the
effective date of this AD, modify the fuel
system wiring along the fuselage and in the
avionics compartment by installing
protective conduit and spacers, in
accordance with the Accomplishment
Instructions of Bombardier Service Bulletin
670BA–24–011, Revision C, dated November
28, 2005.
(2) Actions done before the effective date
of this AD in accordance with Bombardier
Service Bulletin 670BA–24–011, dated
September 7, 2004; Revision A, dated
December 14, 2004; or Revision B, dated
February 28, 2005; are acceptable for
compliance with the corresponding
requirements of this AD.
FAA AD Differences
jlentini on PROD1PC65 with PROPOSALS
Note: This AD differs from the MCAI and/
or service information as follows: No
differences.
Other FAA AD Provisions
(g) The following provisions also apply to
this AD:
(1) Alternative Methods of Compliance
(AMOCs): The Manager, New York Aircraft
Certification Office (ACO), 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: Rocco
Viselli, Aerospace Engineer, Airframe and
Propulsion Branch, ANE–171, FAA, New
York ACO, 1600 Stewart Avenue, Suite 410,
Westbury, New York 11590; telephone (516)
228–7331; fax (516) 794–5531. 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.
(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 FAAapproved 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.
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(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.
54751
result in inability of the structure to
carry horizontal stabilizer flight loads,
and loss of controllability of the
airplane.
[Docket No. FAA–2008–0981; Directorate
Identifier 2008–NM–073–AD]
We must receive comments on
this proposed AD by November 7, 2008.
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.
For service information identified in
this AD, contact Boeing Commercial
Airplanes, P.O. Box 3707, Seattle,
Washington 98124–2207.
RIN 2120–AA64
Examining the AD Docket
Airworthiness Directives; Boeing
Model 747 Airplanes
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 proposed 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: Ivan
Li, Aerospace Engineer, Airframe
Branch, ANM–120S, FAA, Seattle
Aircraft Certification Office, 1601 Lind
Avenue, SW., Renton, Washington
98057–3356; telephone (425) 917–6437;
fax (425) 917–6590.
SUPPLEMENTARY INFORMATION:
Related Information
(h) Refer to MCAI Canadian Airworthiness
Directive CF–2008–25, dated July 3, 2008,
and Bombardier Service Bulletin 670BA–24–
011, Revision C, dated November 28, 2005,
for related information.
Issued in Renton, Washington, on
September 12, 2008.
Michael Kaszycki,
Acting Manager, Transport Airplane
Directorate, Aircraft Certification Service.
[FR Doc. E8–22218 Filed 9–22–08; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking
(NPRM).
AGENCY:
SUMMARY: The FAA proposes to
supersede an existing airworthiness
directive (AD) that applies to certain
Boeing Model 747 airplanes. The
existing AD currently requires repetitive
inspections of the body station (BS)
2598 bulkhead, and corrective actions if
necessary. The existing AD also
currently requires a terminating
modification for the repetitive
inspections and a post-modification
inspection of the modified area. This
proposed AD would continue requiring
those actions with revised service
information. For certain airplanes, this
proposed AD would require new
repetitive inspections, an interim
modification, and post-interim
modification inspections. For certain
airplanes, this proposed AD also would
require replacing any previously
repaired aft inner chord and reinstalling
the terminating modification. This
proposed AD results from reports of
cracked aft inner chords on airplanes
after certain requirements of the existing
AD were done. We are proposing this
AD to prevent fatigue cracking of the BS
2598 bulkhead structure, which could
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DATES:
Comments Invited
We invite you to send any written
relevant data, views, or arguments about
this proposed AD. Send your comments
to an address listed under the
ADDRESSES section. Include ‘‘Docket No.
FAA–2008–0981; Directorate Identifier
2008–NM–073–AD’’ at the beginning of
your comments. We specifically invite
comments on the overall regulatory,
economic, environmental, and energy
aspects of this proposed AD. We will
consider all comments received by the
closing date and may amend this
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Federal Register / Vol. 73, No. 185 / Tuesday, September 23, 2008 / Proposed Rules
proposed AD because of those
comments.
We will post all comments we
receive, without change, to https://
www.regulations.gov, including any
personal information you provide. We
will also post a report summarizing each
substantive verbal contact we receive
about this proposed AD.
Discussion
On February 22, 2006, we issued AD
2006–05–06, amendment 39–14503 (71
FR 12125, March 9, 2006), for certain
Boeing Model 747 airplanes. That AD
requires repetitive inspections of the
body station (BS) 2598 bulkhead, and
corrective action if necessary. That AD
also requires modification of the
bulkhead, including a one-time
inspection and corrective action if
necessary, which terminates certain
repetitive inspections. In addition, that
AD also requires a post-modification
inspection of the modified area. That
AD resulted from reports of fatigue
cracking on BS 2598 bulkhead. We
issued that AD to prevent fatigue
cracking of the BS 2598 bulkhead
structure, which could result in
inability of the structure to carry
horizontal stabilizer flight loads, and
loss of controllability of the airplane.
jlentini on PROD1PC65 with PROPOSALS
Actions Since Existing AD Was Issued
Since we issued AD 2006–05–06, we
have received a report of a cracked aft
inner chord that was completely severed
and a 0.5-inch crack in the adjacent
frame support on an in-service airplane.
These cracks have been attributed to
fatigue. The airplane had accumulated
9,988 total flight cycles and 68,081 total
flight hours. A surface high frequency
eddy current (HFEC) inspection had
been done on the aft inner chord as
required by AD 2006–05–06. In
addition, we have received reports of
cracked aft inner chords that had been
previously repaired and not replaced
before the bulkhead was modified in
accordance with AD 2006–05–06.
Repaired chords can have an active
crack tip that may continue to
propagate, even if the area has been
reinforced.
Therefore, we have determined that in
addition to the repetitive surface HFEC
inspections required by AD 2006–05–
06, repetitive open hole surface HFEC
inspections are necessary to detect
cracks that are beneath the surface of the
aft inner chords. We also have
determined that the terminating
modification, if installed with a repaired
aft inner chord in place as required by
AD 2006–05–06, does not adequately
address the identified unsafe condition,
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16:39 Sep 22, 2008
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and that further rulemaking is
necessary.
Relevant Service Information
We have reviewed Revision 4 of
Boeing Alert Service Bulletin 747–
53A2427, dated March 6, 2008 (AD
2006–05–06 refers to Boeing Alert
Service Bulletin 747–53A2427, Revision
2, dated October 5, 2000; or Revision 3,
dated September 27, 2001; as
appropriate sources of service
information for accomplishing certain
requirements). The repetitive surface
HFEC inspections described in Revision
4 are identical to those in earlier
revisions of the service bulletin.
Revision 4 adds new repetitive open
hole HFEC inspections to detect cracks
in the bulkhead splice fitting, frame
support fitting, and forward and aft
inner chords on the left and right side
of the BS 2598 bulkhead, and repair if
necessary. Revision 4 also adds a new
interim modification for the aft inner
chords, which defers the repetitive
surface and open hole HFEC
inspections. The compliance time for
accomplishing the initial open hole
inspection is before 6,000 or 16,000 total
flight cycles (depending on the airplane
configuration), or within 1,500 flight
cycles after the date on Revision 4 of the
service bulletin, whichever occurs later.
The compliance time for accomplishing
repetitive surface and open hole HFEC
inspections is within 1,500 flight cycles
after the last surface HFEC inspection of
the forward side of the bulkhead or
within 6,000 flight cycles after
installation of the structural repair
manual repair or interim modification,
depending on the airplane
configuration.
We also have reviewed Revision 1 of
Boeing Service Bulletin 747–53–2473,
dated February 20, 2007 (AD 2006–05–
06 refers to Boeing Service Bulletin
747–53–2473, dated March 24, 2005; as
an appropriate source of service
information for accomplishing the
terminating modification). Revision 1
removes the option to re-install an aft
inner chord that has been repaired
before accomplishing the terminating
modification. The modification and
related investigative and corrective
actions are essentially identical to those
specified in Boeing Service Bulletin
747–53–2473, dated March 24, 2005.
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
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condition that is likely to develop on
other airplanes of the same type design.
For this reason, we are proposing this
AD, which would supersede AD 2006–
05–06 and would retain the
requirements of the existing AD. This
proposed AD would also require
accomplishing the actions specified in
service information described
previously, except as discussed under
‘‘Differences Between the Proposed AD
and Service Information.’’
Differences Between the Proposed AD
and Service Information
The service information described
previously specifies to contact the
manufacturer for instructions on how to
repair certain conditions, but this
proposed AD would require repairing
those conditions in one of the following
ways:
• Using a method that we approve; or
• Using data that meet the
certification basis of the airplane, and
that have been approved by an
Authorized Representative for the
Boeing Commercial Airplanes
Delegation Option Authorization
Organization whom we have authorized
to make those findings.
For certain airplanes, Boeing Service
Bulletin 747–53–2473, Revision 1, does
not specify a compliance time for
replacing the previously repaired aft
inner chord and reinstalling the
terminating modification. In developing
an appropriate compliance time for
these proposed actions, we considered
the degree of urgency associated with
the subject unsafe condition, the
manufacturer’s recommendation for an
appropriate compliance time, and the
average utilization of the affected fleet.
In light of these factors, we find that a
compliance time of within 3,000 flight
cycles after doing the modification
required by paragraph (l) of this AD, or
within 1,500 flight cycles after the
effective date of this AD, whichever
occurs later, represents an appropriate
interval of time for affected airplanes to
continue to operate without
compromising safety. This difference
has been coordinated with Boeing.
Explanation of Change Made to
Requirements of AD 2006–05–06
Retained in This AD
We have simplified paragraphs (g), (i),
and (k) of this AD by referring to the
‘‘Alternative Methods of Compliance
(AMOCs)’’ paragraph of this AD for
repair methods.
Costs of Compliance
There are about 998 airplanes of the
affected design in the worldwide fleet.
The following table provides the
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Federal Register / Vol. 73, No. 185 / Tuesday, September 23, 2008 / Proposed Rules
estimated costs for U.S. operators to
comply with this proposed AD.
ESTIMATED COSTS
Action
Work hours
Average
labor rate
per hour
Parts
Number of
U.S.registered
airplanes
Cost per airplane
Fleet cost
Surface HFEC inspections
and open hole HFEC inspections.
Detailed inspections ..........
2
$80
None ...........
$160, per inspection cycle
162
$25,920, per inspection
cycle.
2
80
None ...........
$160, per inspection cycle
162
Interim modification ...........
Replacement of Previously
Repaired Aft Inner
Chords.
Terminating modification ...
Post-terminating modification inspection.
4
2
80
80
$4,000 .........
None ...........
$4,320 ..............................
$160 .................................
162
162
$25,920, per inspection
cycle.
$699,840.
$25,920.
126
4
80
80
$33,716 .......
None ...........
$43,796 ............................
$320 .................................
162
162
$7,094,952.
$51,840.
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.
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Regulatory Findings
16:39 Sep 22, 2008
Jkt 214001
series airplanes, certificated in any category,
line numbers 1 through 1307 inclusive.
Unsafe Condition
Air transportation, Aircraft, Aviation
safety, Safety.
(d) This AD results from reports of cracked
aft inner chords on airplanes after certain
requirements of the existing AD were done.
We are issuing this AD to prevent fatigue
cracking of the body station (BS) 2598
bulkhead structure, which could result in
inability of the structure to carry horizontal
stabilizer flight loads, and loss of
controllability of the airplane.
The Proposed Amendment
Compliance
Accordingly, under the authority
delegated to me by the Administrator,
the FAA proposes to amend 14 CFR part
39 as follows:
Requirements of AD 2006–05–06
List of Subjects in 14 CFR Part 39
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
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
VerDate Aug<31>2005
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.
[Amended]
2. The Federal Aviation
Administration (FAA) amends § 39.13
by removing amendment 39–14503 (71
FR 12125, March 9, 2006) and adding
the following new airworthiness
directive (AD):
Boeing: Docket No. FAA–2008–0981;
Directorate Identifier 2008–NM–073–AD.
Comments Due Date
(a) The FAA must receive comments on
this AD action by November 7, 2008.
Affected ADs
(b) This AD supersedes AD 2006–05–06.
Applicability
(c) This AD applies to Boeing Model 747–
100, 747–100B, 747–100B SUD, 747–200B,
747–200C, 747–200F, 747–300, 747–400,
747–400D, 747–400F, 747SR, and 747SP
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(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.
Repetitive High Frequency Eddy Current
(HFEC) Inspections of the Bulkhead Frame
Supports
(f) Before the accumulation of 10,000 total
flight cycles, or within 1,000 flight cycles
after August 16, 2001 (the effective date of
AD 2001–14–07), whichever occurs later: Do
an open-hole HFEC inspection to find
cracking of the bulkhead frame support
under the hinge support fittings of the
horizontal stabilizer on the left and right
sides at BS 2598, in accordance with Figure
2 of the Accomplishment Instructions of
Boeing Service Bulletin 747–53A2449,
Revision 1, dated May 24, 2001; or Revision
2, dated March 14, 2002. Repeat the
inspection after that at intervals not to exceed
3,000 flight cycles. Inspections accomplished
before August 16, 2001, per Boeing Alert
Service Bulletin 747–53A2449, dated June 8,
2000, are considered acceptable for
compliance with the applicable inspection
specified in this paragraph.
Repair of Any Cracked Bulkhead Frame
Support
(g) If any cracking is found during any
inspection required by paragraph (f) of this
AD, before further flight, repair using a
method approved in accordance with the
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procedures specified in paragraph (w) of this
AD.
Repetitive Inspections of Inner Chords,
Frame Support, and Splice Fitting
(h) Except as provided by paragraph (n) of
this AD: Do a surface HFEC inspection of the
forward and aft inner chords, the frame
support, and the splice fitting of the forward
inner chord of the upper corners of the
station 2598 bulkhead to find cracking, in
accordance with the Accomplishment
Instructions of Boeing Alert Service Bulletin
747–53A2427, Revision 2, dated October 5,
2000; or Revision 3, dated September 27,
2001; at the latest of the times specified in
paragraphs (h)(1) and (h)(2) of this AD, as
applicable. Repeat the inspection after that at
intervals not to exceed 1,500 flight cycles.
(1) For airplanes having line numbers 1
through 1241 inclusive:
(i) Before the accumulation of 6,000 total
flight cycles.
(ii) Within 500 flight cycles after August
28, 2001 (the effective date of AD 2001–15–
03).
(iii) For airplanes inspected before August
28, 2001, in accordance with Boeing Alert
Service Bulletin 747–53A2427, dated
December 17, 1998 (including inspections of
the splice fitting), or Revision 1, dated
October 28, 1999: Within 1,500 flight cycles
after accomplishment of the last inspection
done in accordance with the original service
bulletin or Revision 1, as applicable.
(2) For airplanes having line numbers 1242
through 1307 inclusive:
(i) Before the accumulation of 16,000 total
flight cycles.
(ii) Within 500 flight cycles after August
28, 2001.
(iii) For airplanes inspected before August
28, 2001, in accordance with Boeing Alert
Service Bulletin 747–53A2427, dated
December 17, 1998 (including inspections of
the splice fitting), or Revision 1, dated
October 28, 1999: Within 1,500 flight cycles
after accomplishment of the last inspection
done in accordance with the original service
bulletin or Revision 1, as applicable.
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Repair of Any Cracked Inner Chord, Frame
Support, or Splice Fitting
(i) If any cracking is found during the
inspections required by paragraph (h) of this
AD, before further flight, repair in accordance
with the Accomplishment Instructions of
Boeing Alert Service Bulletin 747–53A2427,
Revision 2, dated October 5, 2000; or
Revision 3, dated September 27, 2001; except
as provided by paragraph (n) of this AD, and
except where the alert service bulletin
specifies that the manufacturer may be
contacted for disposition of certain repair
conditions, before further flight, repair using
a method approved in accordance with the
procedures specified in paragraph (w) of this
AD.
Repetitive Detailed Inspections of BS 2598
Bulkhead
(j) Before the accumulation of 10,000 total
flight cycles, or within 1,000 flight cycles
after October 27, 2003 (the effective date of
AD 2003–19–08), whichever is later: Do a
detailed inspection of the BS 2598 bulkhead
for discrepancies (cracking, elongated
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16:39 Sep 22, 2008
Jkt 214001
fastener holes) of the areas specified in
paragraphs (j)(1) and (j)(2) of this AD, in
accordance with the Accomplishment
Instructions of Boeing Alert Service Bulletin
747–53A2467, dated July 26, 2001; or
Revision 1, dated April 28, 2005. Repeat the
inspections after that at intervals not to
exceed 3,000 flight cycles.
(1) The lower aft inner chords.
(2) The upper aft outer chords, and the
diagonal brace attachment fittings, flanges,
and rods.
Note 1: For the purposes of this AD, a
detailed inspection is ‘‘an intensive
examination of a specific item, installation,
or assembly to detect damage, failure, or
irregularity. Available lighting is normally
supplemented with a direct source of good
lighting at an intensity deemed appropriate.
Inspection aids such as mirrors, magnifying
lenses, etc. may be necessary. Surface
cleaning and elaborate procedures may be
required.’’
Repair of Any Cracked BS 2598 Bulkhead
(k) If any discrepancy is found during any
inspection required by paragraph (j) of this
AD: Before further flight, repair in
accordance with the Accomplishment
Instructions of Boeing Alert Service Bulletin
747–53A2467, dated July 26, 2001; or
Revision 1, dated April 28, 2005. If the
service bulletin specifies to contact Boeing
for appropriate action: Before further flight,
repair using a method approved in
accordance with the procedures specified in
paragraph (w) of this AD.
Terminating Modification
(l) Except as provided by paragraphs (p)
and (q) of this AD: Before the accumulation
of 20,000 total flight cycles, or within 48
months after April 13, 2006 (the effective
date of AD 2006–05–06), whichever occurs
later, modify the bulkhead by doing all
applicable actions including surface and
open-hole HFEC inspections for cracking of
the upper forward inner chords, aft inner
chords, upper splice fittings, and frame
support fittings, as specified in the
Accomplishment Instructions of Boeing
Service Bulletin 747–53–2473, dated March
24, 2005. Repair any cracks before further
flight in accordance with the service bulletin.
Where the service bulletin specifies that the
manufacturer may be contacted for
disposition of certain repair conditions:
Before further flight, repair the cracks using
a method approved in accordance with the
procedures specified in paragraph (w) of this
AD. Accomplishment of the modification
terminates the requirements of paragraph (f),
(h), and (j)(1) of this AD.
Post-Modification Inspection and Repair
(m) Within 20,000 flight cycles after the
modification required by paragraph (l) of this
AD, inspect the BS 2598 bulkhead for cracks,
and repair any cracks before further flight, in
accordance with a method approved by the
Manager, Seattle Aircraft Certification Office
(ACO).
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New Requirements of This AD
New Revision of Service Bulletin
(n) As of the effective date of this AD, use
only the Accomplishment Instructions of
Boeing Alert Service Bulletin 747–53A2427,
Revision 4, dated March 6, 2008, to do the
repetitive surface HFEC inspections required
by paragraph (h) of this AD and the repair
required by paragraph (i) of this AD.
Terminating Repair for Repetitive Surface
HFEC Inspections
(o) As of the effective date of this AD,
accomplishment of the aft inner chord repair
required by paragraph (i) of this AD in
accordance with the applicable structural
repair manual (SRM) specified in the
Accomplishment Instructions of Boeing Alert
Service Bulletin 747–53A2427, Revision 4,
dated March 6, 2008, ends the repetitive
surface HFEC inspections required by
paragraph (h) of this AD for that side of the
bulkhead only.
Replacement of Previously Repaired Aft
Inner Chord and Reinstallation of
Terminating Modification
(p) For airplanes on which the terminating
modification required by paragraph (l) of this
AD has been done before the effective date
of this AD, and on which any previously
repaired aft inner chord was not replaced
during that terminating modification: Within
3,000 flight cycles after doing the
modification, or within 1,500 flight cycles
after the effective date of this AD, whichever
occurs later, replace any previously repaired
aft inner chord with a new aft inner chord
and reinstall the terminating modification
using a method approved in accordance with
the procedures specified in paragraph (w) of
this AD. Accomplishment of the replacement
and reinstallation of the terminating
modification terminates the requirements of
paragraphs (l) and (m) of this AD and
repetitive inspections required by this AD,
except for the inspections specified in
paragraph (r) of this AD.
Revised Terminating Modification
(q) For airplanes on which the terminating
modification required by paragraph (l) of this
AD has not been done as of the effective date
of this AD: Before the accumulation of 20,000
total flight cycles, or within 18 months after
the effective date of this AD, whichever
occurs later, modify and do applicable
relative investigative and corrective actions
by doing all the applicable actions specified
in the Accomplishment Instructions of
Boeing Service Bulletin 747–53–2473,
Revision 1, dated February 20, 2007; except
where the service bulletin specifies that the
manufacturer may be contacted for
disposition of certain repair conditions,
before further flight, repair the cracks using
a method approved in accordance with the
procedures specified in paragraph (w) of this
AD. The applicable related investigative and
corrective actions must be done before
further flight. Accomplishment of the
replacement and reinstallation of the
terminating modification terminates the
requirements of paragraphs (l) and (m) of this
AD and repetitive inspections required by
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Federal Register / Vol. 73, No. 185 / Tuesday, September 23, 2008 / Proposed Rules
this AD, except for the inspections specified
in paragraph (r) of this AD.
Post-Modification Inspection and Repair
(r) Within 20,000 flight cycles after the
modification required by paragraph (p) or (q)
of this AD, as applicable, inspect the BS 2598
bulkhead for cracks, and repair any crack
before further flight, in accordance with a
method approved by the Manager, Seattle
ACO.
Open Hole HFEC Inspection(s) and
Terminating Repair
(s) For airplanes on which the terminating
modification required by paragraph (l) or (q)
of this AD has not been done: Do an initial
open hole HFEC inspection to detect cracks
in the bulkhead splice fitting, frame support
fitting, and forward and aft inner chords on
the left and right sides of the BS 2598
bulkhead, in accordance with the
Accomplishment Instructions of Boeing Alert
Service Bulletin 747–53A2427, Revision 4,
dated March 6, 2008. Do the initial
inspection at the applicable time specified in
Table 1 or 3 of paragraph 1.E., ‘‘Compliance,’’
of the service bulletin; except, where the
service bulletin specifies a compliance time
after the date on the service bulletin, this AD
requires compliance within the specified
compliance time after the effective date of
this AD.
(1) If no crack is detected, repeat the open
hole HFEC inspection thereafter at intervals
not to exceed 1,500 flight cycles.
(2) If any crack is detected, before further
flight, repair it in accordance with the service
bulletin; except, where the service bulletin
specifies to contact Boeing for appropriate
action, before further flight, repair the crack
using a method approved in accordance with
the procedures specified in paragraph (w) of
this AD. Accomplishment of the aft inner
chord repair in accordance with the
applicable SRM specified in the
Accomplishment Instructions of the service
bulletin ends the repetitive open hole HFEC
inspections required by paragraphs (h) and
(s)(1) of this AD for that side of the bulkhead
only.
jlentini on PROD1PC65 with PROPOSALS
Interim Modification
(t) For Group 1 airplanes, as identified in
Boeing Alert Service Bulletin 747–53A2427,
Revision 4, dated March 6, 2008, on which
the terminating modification required by
paragraph (l) or (q) of this AD has not been
done: Before the accumulation of 12,000 total
flight cycles, or within 1,500 flight cycles
after the effective date of this AD, whichever
occurs later, install the interim modification
for the aft inner chords, in accordance with
the Accomplishment Instructions of the
service bulletin. Accomplishment of the
interim modification ends the repetitive open
hole and surface HFEC inspections required
by paragraphs (h) and (s)(1) of this AD.
Post-Interim Modification/Repair Repetitive
Surface and Open Hole HFEC Inspections
(u) For airplanes on which the interim
modification required by paragraph (t) of this
AD has been done or the repair of any
cracked aft inner chord has been done in
accordance with the SRM specified in the
Accomplishment Instructions of Boeing Alert
VerDate Aug<31>2005
16:39 Sep 22, 2008
Jkt 214001
54755
Service Bulletin 747–53A2427, Revision 4,
dated March 6, 2008, as required by
paragraph (i) or (s)(2) of this AD; and on
which the terminating modification required
by paragraph (l) or (q) of this AD has not been
done: At the applicable times specified in
Table 1, 2, or 3 of paragraph 1.E.,
‘‘Compliance,’’ of the service bulletin, do a
surface HFEC inspection to detect cracks on
the forward side (unmodified area) of the
bulkhead and open hole and surface HFEC
inspections to detect cracks in the modified
or repaired area, in accordance with the
Accomplishment Instructions of Boeing Alert
Service Bulletin 747–53A2427, Revision 4,
dated March 6, 2008. Repeat the open hole
and surface HFEC inspections thereafter at
intervals not to exceed 1,500 flight cycles,
until the modification required by paragraph
(q) of this AD is done, as applicable; except,
for airplanes on which the repair of any
cracked aft inner chord has been done on
only one side of the bulkhead in accordance
with the applicable SRM as required by
paragraph (i) or (s)(2) of this AD, the
repetitive open hole and surface HFEC
inspections required by paragraph (h) and
(s)(1) of this AD must continue to be done for
the other side of the bulkhead.
(4) AMOCs approved previously in
accordance with AD 2006–05–06 are
approved as AMOCs for the corresponding
provisions of this AD.
Repair of Any Cracked Inner Chord, Splice
Fitting, or Frame Support Fitting
(v) If any crack is detected during any open
hole or surface HFEC inspection required by
paragraph (u) of this AD, before further flight,
repair any cracked inner chord, splice fitting,
or frame support fitting, in accordance with
the Accomplishment Instructions of Boeing
Alert Service Bulletin 747–53A2427,
Revision 4, dated March 6, 2008; except,
where the service bulletin specifies to contact
Boeing for appropriate action, before further
flight, repair the crack using a method
approved in accordance with the procedures
specified in paragraph (w) of this AD.
AGENCY:
Alternative Methods of Compliance
(AMOCs)
(w)(1) The Manager, Seattle ACO, FAA,
ATTN: Ivan Li, Aerospace Engineer, Airframe
Branch, ANM–120S, FAA, Seattle ACO, 1601
Lind Avenue, SW., Renton, Washington
98057–3356; telephone (425) 917–6437; fax
(425) 917–6590; has the authority to approve
AMOCs for this AD, if requested using 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.
PO 00000
Frm 00016
Fmt 4702
Sfmt 4702
Issued in Renton, Washington, on
September 11, 2008.
Michael Kaszycki,
Acting Manager, Transport Airplane
Directorate, Aircraft Certification Service.
[FR Doc. E8–22215 Filed 9–22–08; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2008–1006; Directorate
Identifier 2008–NM–110–AD]
RIN 2120–AA64
Airworthiness Directives; Boeing
Model 747–100, 747–100B, 747–200B,
747–200C, 747–200F, 747–300, 747SR,
and 747SP Series Airplanes
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking
(NPRM).
SUMMARY: The FAA proposes to
supersede an existing airworthiness
directive (AD) that applies to certain
Boeing Model 747–100, 747–100B, 747–
200B, 747–200C, 747–200F, 747–300,
747SR, and 747SP series airplanes. The
existing AD currently requires an
inspection to determine if acceptable
external skin doublers are installed at
the stringer 6 (S–6) lap splices, between
station (STA) 340 and STA 400. For
airplanes without the acceptable
external skin doublers, the existing AD
requires repetitive related investigative
actions and corrective actions if
necessary. The existing AD also
provides an optional terminating
modification for the repetitive related
investigative actions. This proposed AD
would mandate the optional terminating
modification. This proposed AD results
from a report of cracked fastener holes
at the right S–6 lap splice between STA
340 and STA 380. We are proposing this
AD to prevent cracking in the fuselage
skin, which could result in rapid
decompression and loss of structural
integrity of the airplane.
DATES: We must receive comments on
this proposed AD by November 7, 2008.
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.
E:\FR\FM\23SEP1.SGM
23SEP1
]]>Agencies
[Federal Register Volume 73, Number 185 (Tuesday, September 23, 2008)]
[Proposed Rules]
[Pages 54751-54755]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-22215]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-0981; Directorate Identifier 2008-NM-073-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: The FAA proposes to supersede an existing airworthiness
directive (AD) that applies to certain Boeing Model 747 airplanes. The
existing AD currently requires repetitive inspections of the body
station (BS) 2598 bulkhead, and corrective actions if necessary. The
existing AD also currently requires a terminating modification for the
repetitive inspections and a post-modification inspection of the
modified area. This proposed AD would continue requiring those actions
with revised service information. For certain airplanes, this proposed
AD would require new repetitive inspections, an interim modification,
and post-interim modification inspections. For certain airplanes, this
proposed AD also would require replacing any previously repaired aft
inner chord and reinstalling the terminating modification. This
proposed AD results from reports of cracked aft inner chords on
airplanes after certain requirements of the existing AD were done. We
are proposing this AD to prevent fatigue cracking of the BS 2598
bulkhead structure, which could result in inability of the structure to
carry horizontal stabilizer flight loads, and loss of controllability
of the airplane.
DATES: We must receive comments on this proposed AD by November 7,
2008.
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.
For service information identified in this AD, contact Boeing
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.
Examining the AD Docket
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 proposed 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: Ivan Li, Aerospace Engineer, Airframe
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6437;
fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2008-0981;
Directorate Identifier 2008-NM-073-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this
[[Page 54752]]
proposed AD because of those comments.
We will post all comments we receive, without change, to https://
www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.
Discussion
On February 22, 2006, we issued AD 2006-05-06, amendment 39-14503
(71 FR 12125, March 9, 2006), for certain Boeing Model 747 airplanes.
That AD requires repetitive inspections of the body station (BS) 2598
bulkhead, and corrective action if necessary. That AD also requires
modification of the bulkhead, including a one-time inspection and
corrective action if necessary, which terminates certain repetitive
inspections. In addition, that AD also requires a post-modification
inspection of the modified area. That AD resulted from reports of
fatigue cracking on BS 2598 bulkhead. We issued that AD to prevent
fatigue cracking of the BS 2598 bulkhead structure, which could result
in inability of the structure to carry horizontal stabilizer flight
loads, and loss of controllability of the airplane.
Actions Since Existing AD Was Issued
Since we issued AD 2006-05-06, we have received a report of a
cracked aft inner chord that was completely severed and a 0.5-inch
crack in the adjacent frame support on an in-service airplane. These
cracks have been attributed to fatigue. The airplane had accumulated
9,988 total flight cycles and 68,081 total flight hours. A surface high
frequency eddy current (HFEC) inspection had been done on the aft inner
chord as required by AD 2006-05-06. In addition, we have received
reports of cracked aft inner chords that had been previously repaired
and not replaced before the bulkhead was modified in accordance with AD
2006-05-06. Repaired chords can have an active crack tip that may
continue to propagate, even if the area has been reinforced.
Therefore, we have determined that in addition to the repetitive
surface HFEC inspections required by AD 2006-05-06, repetitive open
hole surface HFEC inspections are necessary to detect cracks that are
beneath the surface of the aft inner chords. We also have determined
that the terminating modification, if installed with a repaired aft
inner chord in place as required by AD 2006-05-06, does not adequately
address the identified unsafe condition, and that further rulemaking is
necessary.
Relevant Service Information
We have reviewed Revision 4 of Boeing Alert Service Bulletin 747-
53A2427, dated March 6, 2008 (AD 2006-05-06 refers to Boeing Alert
Service Bulletin 747-53A2427, Revision 2, dated October 5, 2000; or
Revision 3, dated September 27, 2001; as appropriate sources of service
information for accomplishing certain requirements). The repetitive
surface HFEC inspections described in Revision 4 are identical to those
in earlier revisions of the service bulletin. Revision 4 adds new
repetitive open hole HFEC inspections to detect cracks in the bulkhead
splice fitting, frame support fitting, and forward and aft inner chords
on the left and right side of the BS 2598 bulkhead, and repair if
necessary. Revision 4 also adds a new interim modification for the aft
inner chords, which defers the repetitive surface and open hole HFEC
inspections. The compliance time for accomplishing the initial open
hole inspection is before 6,000 or 16,000 total flight cycles
(depending on the airplane configuration), or within 1,500 flight
cycles after the date on Revision 4 of the service bulletin, whichever
occurs later. The compliance time for accomplishing repetitive surface
and open hole HFEC inspections is within 1,500 flight cycles after the
last surface HFEC inspection of the forward side of the bulkhead or
within 6,000 flight cycles after installation of the structural repair
manual repair or interim modification, depending on the airplane
configuration.
We also have reviewed Revision 1 of Boeing Service Bulletin 747-53-
2473, dated February 20, 2007 (AD 2006-05-06 refers to Boeing Service
Bulletin 747-53-2473, dated March 24, 2005; as an appropriate source of
service information for accomplishing the terminating modification).
Revision 1 removes the option to re-install an aft inner chord that has
been repaired before accomplishing the terminating modification. The
modification and related investigative and corrective actions are
essentially identical to those specified in Boeing Service Bulletin
747-53-2473, dated March 24, 2005.
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 develop on other airplanes of the
same type design. For this reason, we are proposing this AD, which
would supersede AD 2006-05-06 and would retain the requirements of the
existing AD. This proposed AD would also require accomplishing the
actions specified in service information described previously, except
as discussed under ``Differences Between the Proposed AD and Service
Information.''
Differences Between the Proposed AD and Service Information
The service information described previously specifies to contact
the manufacturer for instructions on how to repair certain conditions,
but this proposed AD would require repairing those conditions in one of
the following ways:
Using a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by an Authorized Representative
for the Boeing Commercial Airplanes Delegation Option Authorization
Organization whom we have authorized to make those findings.
For certain airplanes, Boeing Service Bulletin 747-53-2473,
Revision 1, does not specify a compliance time for replacing the
previously repaired aft inner chord and reinstalling the terminating
modification. In developing an appropriate compliance time for these
proposed actions, we considered the degree of urgency associated with
the subject unsafe condition, the manufacturer's recommendation for an
appropriate compliance time, and the average utilization of the
affected fleet. In light of these factors, we find that a compliance
time of within 3,000 flight cycles after doing the modification
required by paragraph (l) of this AD, or within 1,500 flight cycles
after the effective date of this AD, whichever occurs later, represents
an appropriate interval of time for affected airplanes to continue to
operate without compromising safety. This difference has been
coordinated with Boeing.
Explanation of Change Made to Requirements of AD 2006-05-06 Retained in
This AD
We have simplified paragraphs (g), (i), and (k) of this AD by
referring to the ``Alternative Methods of Compliance (AMOCs)''
paragraph of this AD for repair methods.
Costs of Compliance
There are about 998 airplanes of the affected design in the
worldwide fleet. The following table provides the
[[Page 54753]]
estimated costs for U.S. operators to comply with this proposed AD.
Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of
Average U.S.-
Action Work hours labor rate Parts Cost per airplane registered Fleet cost
per hour airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Surface HFEC inspections and open 2 $80 None.................... $160, per inspection 162 $25,920, per inspection
hole HFEC inspections. cycle. cycle.
Detailed inspections................. 2 80 None.................... $160, per inspection 162 $25,920, per inspection
cycle. cycle.
Interim modification................. 4 80 $4,000.................. $4,320................. 162 $699,840.
Replacement of Previously Repaired 2 80 None.................... $160................... 162 $25,920.
Aft Inner Chords.
Terminating modification............. 126 80 $33,716................. $43,796................ 162 $7,094,952.
Post-terminating modification 4 80 None.................... $320................... 162 $51,840.
inspection.
--------------------------------------------------------------------------------------------------------------------------------------------------------
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
removing amendment 39-14503 (71 FR 12125, March 9, 2006) and adding the
following new airworthiness directive (AD):
Boeing: Docket No. FAA-2008-0981; Directorate Identifier 2008-NM-
073-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by November
7, 2008.
Affected ADs
(b) This AD supersedes AD 2006-05-06.
Applicability
(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-
400F, 747SR, and 747SP series airplanes, certificated in any
category, line numbers 1 through 1307 inclusive.
Unsafe Condition
(d) This AD results from reports of cracked aft inner chords on
airplanes after certain requirements of the existing AD were done.
We are issuing this AD to prevent fatigue cracking of the body
station (BS) 2598 bulkhead structure, which could result in
inability of the structure to carry horizontal stabilizer flight
loads, and loss of controllability 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.
Requirements of AD 2006-05-06
Repetitive High Frequency Eddy Current (HFEC) Inspections of the
Bulkhead Frame Supports
(f) Before the accumulation of 10,000 total flight cycles, or
within 1,000 flight cycles after August 16, 2001 (the effective date
of AD 2001-14-07), whichever occurs later: Do an open-hole HFEC
inspection to find cracking of the bulkhead frame support under the
hinge support fittings of the horizontal stabilizer on the left and
right sides at BS 2598, in accordance with Figure 2 of the
Accomplishment Instructions of Boeing Service Bulletin 747-53A2449,
Revision 1, dated May 24, 2001; or Revision 2, dated March 14, 2002.
Repeat the inspection after that at intervals not to exceed 3,000
flight cycles. Inspections accomplished before August 16, 2001, per
Boeing Alert Service Bulletin 747-53A2449, dated June 8, 2000, are
considered acceptable for compliance with the applicable inspection
specified in this paragraph.
Repair of Any Cracked Bulkhead Frame Support
(g) If any cracking is found during any inspection required by
paragraph (f) of this AD, before further flight, repair using a
method approved in accordance with the
[[Page 54754]]
procedures specified in paragraph (w) of this AD.
Repetitive Inspections of Inner Chords, Frame Support, and Splice
Fitting
(h) Except as provided by paragraph (n) of this AD: Do a surface
HFEC inspection of the forward and aft inner chords, the frame
support, and the splice fitting of the forward inner chord of the
upper corners of the station 2598 bulkhead to find cracking, in
accordance with the Accomplishment Instructions of Boeing Alert
Service Bulletin 747-53A2427, Revision 2, dated October 5, 2000; or
Revision 3, dated September 27, 2001; at the latest of the times
specified in paragraphs (h)(1) and (h)(2) of this AD, as applicable.
Repeat the inspection after that at intervals not to exceed 1,500
flight cycles.
(1) For airplanes having line numbers 1 through 1241 inclusive:
(i) Before the accumulation of 6,000 total flight cycles.
(ii) Within 500 flight cycles after August 28, 2001 (the
effective date of AD 2001-15-03).
(iii) For airplanes inspected before August 28, 2001, in
accordance with Boeing Alert Service Bulletin 747-53A2427, dated
December 17, 1998 (including inspections of the splice fitting), or
Revision 1, dated October 28, 1999: Within 1,500 flight cycles after
accomplishment of the last inspection done in accordance with the
original service bulletin or Revision 1, as applicable.
(2) For airplanes having line numbers 1242 through 1307
inclusive:
(i) Before the accumulation of 16,000 total flight cycles.
(ii) Within 500 flight cycles after August 28, 2001.
(iii) For airplanes inspected before August 28, 2001, in
accordance with Boeing Alert Service Bulletin 747-53A2427, dated
December 17, 1998 (including inspections of the splice fitting), or
Revision 1, dated October 28, 1999: Within 1,500 flight cycles after
accomplishment of the last inspection done in accordance with the
original service bulletin or Revision 1, as applicable.
Repair of Any Cracked Inner Chord, Frame Support, or Splice Fitting
(i) If any cracking is found during the inspections required by
paragraph (h) of this AD, before further flight, repair in
accordance with the Accomplishment Instructions of Boeing Alert
Service Bulletin 747-53A2427, Revision 2, dated October 5, 2000; or
Revision 3, dated September 27, 2001; except as provided by
paragraph (n) of this AD, and except where the alert service
bulletin specifies that the manufacturer may be contacted for
disposition of certain repair conditions, before further flight,
repair using a method approved in accordance with the procedures
specified in paragraph (w) of this AD.
Repetitive Detailed Inspections of BS 2598 Bulkhead
(j) Before the accumulation of 10,000 total flight cycles, or
within 1,000 flight cycles after October 27, 2003 (the effective
date of AD 2003-19-08), whichever is later: Do a detailed inspection
of the BS 2598 bulkhead for discrepancies (cracking, elongated
fastener holes) of the areas specified in paragraphs (j)(1) and
(j)(2) of this AD, in accordance with the Accomplishment
Instructions of Boeing Alert Service Bulletin 747-53A2467, dated
July 26, 2001; or Revision 1, dated April 28, 2005. Repeat the
inspections after that at intervals not to exceed 3,000 flight
cycles.
(1) The lower aft inner chords.
(2) The upper aft outer chords, and the diagonal brace
attachment fittings, flanges, and rods.
Note 1: For the purposes of this AD, a detailed inspection is
``an intensive examination of a specific item, installation, or
assembly to detect damage, failure, or irregularity. Available
lighting is normally supplemented with a direct source of good
lighting at an intensity deemed appropriate. Inspection aids such as
mirrors, magnifying lenses, etc. may be necessary. Surface cleaning
and elaborate procedures may be required.''
Repair of Any Cracked BS 2598 Bulkhead
(k) If any discrepancy is found during any inspection required
by paragraph (j) of this AD: Before further flight, repair in
accordance with the Accomplishment Instructions of Boeing Alert
Service Bulletin 747-53A2467, dated July 26, 2001; or Revision 1,
dated April 28, 2005. If the service bulletin specifies to contact
Boeing for appropriate action: Before further flight, repair using a
method approved in accordance with the procedures specified in
paragraph (w) of this AD.
Terminating Modification
(l) Except as provided by paragraphs (p) and (q) of this AD:
Before the accumulation of 20,000 total flight cycles, or within 48
months after April 13, 2006 (the effective date of AD 2006-05-06),
whichever occurs later, modify the bulkhead by doing all applicable
actions including surface and open-hole HFEC inspections for
cracking of the upper forward inner chords, aft inner chords, upper
splice fittings, and frame support fittings, as specified in the
Accomplishment Instructions of Boeing Service Bulletin 747-53-2473,
dated March 24, 2005. Repair any cracks before further flight in
accordance with the service bulletin. Where the service bulletin
specifies that the manufacturer may be contacted for disposition of
certain repair conditions: Before further flight, repair the cracks
using a method approved in accordance with the procedures specified
in paragraph (w) of this AD. Accomplishment of the modification
terminates the requirements of paragraph (f), (h), and (j)(1) of
this AD.
Post-Modification Inspection and Repair
(m) Within 20,000 flight cycles after the modification required
by paragraph (l) of this AD, inspect the BS 2598 bulkhead for
cracks, and repair any cracks before further flight, in accordance
with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO).
New Requirements of This AD
New Revision of Service Bulletin
(n) As of the effective date of this AD, use only the
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2427, Revision 4, dated March 6, 2008, to do the repetitive
surface HFEC inspections required by paragraph (h) of this AD and
the repair required by paragraph (i) of this AD.
Terminating Repair for Repetitive Surface HFEC Inspections
(o) As of the effective date of this AD, accomplishment of the
aft inner chord repair required by paragraph (i) of this AD in
accordance with the applicable structural repair manual (SRM)
specified in the Accomplishment Instructions of Boeing Alert Service
Bulletin 747-53A2427, Revision 4, dated March 6, 2008, ends the
repetitive surface HFEC inspections required by paragraph (h) of
this AD for that side of the bulkhead only.
Replacement of Previously Repaired Aft Inner Chord and Reinstallation
of Terminating Modification
(p) For airplanes on which the terminating modification required
by paragraph (l) of this AD has been done before the effective date
of this AD, and on which any previously repaired aft inner chord was
not replaced during that terminating modification: Within 3,000
flight cycles after doing the modification, or within 1,500 flight
cycles after the effective date of this AD, whichever occurs later,
replace any previously repaired aft inner chord with a new aft inner
chord and reinstall the terminating modification using a method
approved in accordance with the procedures specified in paragraph
(w) of this AD. Accomplishment of the replacement and reinstallation
of the terminating modification terminates the requirements of
paragraphs (l) and (m) of this AD and repetitive inspections
required by this AD, except for the inspections specified in
paragraph (r) of this AD.
Revised Terminating Modification
(q) For airplanes on which the terminating modification required
by paragraph (l) of this AD has not been done as of the effective
date of this AD: Before the accumulation of 20,000 total flight
cycles, or within 18 months after the effective date of this AD,
whichever occurs later, modify and do applicable relative
investigative and corrective actions by doing all the applicable
actions specified in the Accomplishment Instructions of Boeing
Service Bulletin 747-53-2473, Revision 1, dated February 20, 2007;
except where the service bulletin specifies that the manufacturer
may be contacted for disposition of certain repair conditions,
before further flight, repair the cracks using a method approved in
accordance with the procedures specified in paragraph (w) of this
AD. The applicable related investigative and corrective actions must
be done before further flight. Accomplishment of the replacement and
reinstallation of the terminating modification terminates the
requirements of paragraphs (l) and (m) of this AD and repetitive
inspections required by
[[Page 54755]]
this AD, except for the inspections specified in paragraph (r) of
this AD.
Post-Modification Inspection and Repair
(r) Within 20,000 flight cycles after the modification required
by paragraph (p) or (q) of this AD, as applicable, inspect the BS
2598 bulkhead for cracks, and repair any crack before further
flight, in accordance with a method approved by the Manager, Seattle
ACO.
Open Hole HFEC Inspection(s) and Terminating Repair
(s) For airplanes on which the terminating modification required
by paragraph (l) or (q) of this AD has not been done: Do an initial
open hole HFEC inspection to detect cracks in the bulkhead splice
fitting, frame support fitting, and forward and aft inner chords on
the left and right sides of the BS 2598 bulkhead, in accordance with
the Accomplishment Instructions of Boeing Alert Service Bulletin
747-53A2427, Revision 4, dated March 6, 2008. Do the initial
inspection at the applicable time specified in Table 1 or 3 of
paragraph 1.E., ``Compliance,'' of the service bulletin; except,
where the service bulletin specifies a compliance time after the
date on the service bulletin, this AD requires compliance within the
specified compliance time after the effective date of this AD.
(1) If no crack is detected, repeat the open hole HFEC
inspection thereafter at intervals not to exceed 1,500 flight
cycles.
(2) If any crack is detected, before further flight, repair it
in accordance with the service bulletin; except, where the service
bulletin specifies to contact Boeing for appropriate action, before
further flight, repair the crack using a method approved in
accordance with the procedures specified in paragraph (w) of this
AD. Accomplishment of the aft inner chord repair in accordance with
the applicable SRM specified in the Accomplishment Instructions of
the service bulletin ends the repetitive open hole HFEC inspections
required by paragraphs (h) and (s)(1) of this AD for that side of
the bulkhead only.
Interim Modification
(t) For Group 1 airplanes, as identified in Boeing Alert Service
Bulletin 747-53A2427, Revision 4, dated March 6, 2008, on which the
terminating modification required by paragraph (l) or (q) of this AD
has not been done: Before the accumulation of 12,000 total flight
cycles, or within 1,500 flight cycles after the effective date of
this AD, whichever occurs later, install the interim modification
for the aft inner chords, in accordance with the Accomplishment
Instructions of the service bulletin. Accomplishment of the interim
modification ends the repetitive open hole and surface HFEC
inspections required by paragraphs (h) and (s)(1) of this AD.
Post-Interim Modification/Repair Repetitive Surface and Open Hole HFEC
Inspections
(u) For airplanes on which the interim modification required by
paragraph (t) of this AD has been done or the repair of any cracked
aft inner chord has been done in accordance with the SRM specified
in the Accomplishment Instructions of Boeing Alert Service Bulletin
747-53A2427, Revision 4, dated March 6, 2008, as required by
paragraph (i) or (s)(2) of this AD; and on which the terminating
modification required by paragraph (l) or (q) of this AD has not
been done: At the applicable times specified in Table 1, 2, or 3 of
paragraph 1.E., ``Compliance,'' of the service bulletin, do a
surface HFEC inspection to detect cracks on the forward side
(unmodified area) of the bulkhead and open hole and surface HFEC
inspections to detect cracks in the modified or repaired area, in
accordance with the Accomplishment Instructions of Boeing Alert
Service Bulletin 747-53A2427, Revision 4, dated March 6, 2008.
Repeat the open hole and surface HFEC inspections thereafter at
intervals not to exceed 1,500 flight cycles, until the modification
required by paragraph (q) of this AD is done, as applicable; except,
for airplanes on which the repair of any cracked aft inner chord has
been done on only one side of the bulkhead in accordance with the
applicable SRM as required by paragraph (i) or (s)(2) of this AD,
the repetitive open hole and surface HFEC inspections required by
paragraph (h) and (s)(1) of this AD must continue to be done for the
other side of the bulkhead.
Repair of Any Cracked Inner Chord, Splice Fitting, or Frame Support
Fitting
(v) If any crack is detected during any open hole or surface
HFEC inspection required by paragraph (u) of this AD, before further
flight, repair any cracked inner chord, splice fitting, or frame
support fitting, in accordance with the Accomplishment Instructions
of Boeing Alert Service Bulletin 747-53A2427, Revision 4, dated
March 6, 2008; except, where the service bulletin specifies to
contact Boeing for appropriate action, before further flight, repair
the crack using a method approved in accordance with the procedures
specified in paragraph (w) of this AD.
Alternative Methods of Compliance (AMOCs)
(w)(1) The Manager, Seattle ACO, FAA, ATTN: Ivan Li, Aerospace
Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 1601 Lind
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-
6437; fax (425) 917-6590; has the authority to approve AMOCs for
this AD, if requested using 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.
(4) AMOCs approved previously in accordance with AD 2006-05-06
are approved as AMOCs for the corresponding provisions of this AD.
Issued in Renton, Washington, on September 11, 2008.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-22215 Filed 9-22-08; 8:45 am]
BILLING CODE 4910-13-P
