[Federal Register Volume 77, Number 98 (Monday, May 21, 2012)]
[Rules and Regulations]
[Pages 29857-29861]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-11869]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0645; Directorate Identifier 2010-NM-009-AD; 
Amendment 39-17052; AD 2012-10-03]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are superseding an existing airworthiness directive (AD) 
for certain The Boeing Company Model 747 series airplanes. That AD 
currently requires repetitive inspections for cracks of the fuselage 
skin lap splice between body station (BS) 400 and BS 520 at stringers 
S-6L and S-6R, and repair if necessary. This new AD shortens the 
interval for the repetitive inspections, requires modification for 
certain airplanes, and requires certain post-modification inspections 
for other airplanes. This AD was prompted by reports of multiple 
adjacent cracks on an airplane, and a recent fleet-wide evaluation of 
widespread fatigue damage of skin lap joints, which indicated the need 
for revised procedures and reduced compliance times. We are issuing 
this AD to detect and correct cracking of the fuselage skin lap splice 
between BS 400 and BS 520 at stringers S-6L and S-6R, which could 
result in sudden loss of cabin pressurization and the inability of the 
fuselage to withstand fail-safe loads.

DATES: This AD is effective June 25, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of June 25, 2012.

ADDRESSES: For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; email [email protected]; 
Internet https://www.myboeingfleet.com. You may review copies of the 
referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue SW., Renton, Washington. For information 
on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (phone: 800-647-5527) is Document Management Facility, 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Bill Ashforth, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: 425-
917-6432; fax: 425-917-6590; email: [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to supersede AD 90-21-17, Amendment 39-6768 (55 FR 41510, 
October 12, 1990). That AD applies to the specified products. The NPRM 
was published in the Federal Register on June 29, 2011 (76 FR 38074). 
That NPRM proposed to continue to require repetitive inspections for 
cracks of the fuselage skin lap splice between body station (BS) 400 
and BS 520 at stringers S-6L and S-6R, and repair if necessary; and 
added modification for certain airplanes and certain post-modification 
inspections for other airplanes.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
(76 FR 38074, June 29, 2011) and the FAA's response to each comment.

[[Page 29858]]

Request To Remove Conflicting Requirement

    Boeing stated that certain compliance times conflict in the 
proposed AD (76 FR 38074, June 29, 2011). To resolve the conflict, 
Boeing requested that we remove paragraph (k) from the proposed AD. 
(Paragraph (k) was retained from AD 90-21-17, Amendment 39-6768 (55 FR 
41510, October 12, 1990).) The initial compliance time for the 
inspections specified in paragraphs (k), (l), and (m) of the proposed 
AD is 10,000 flight cycles after certain modifications have been done. 
Boeing noted that the repetitive interval is 5,000 flight cycles for 
paragraph (k) of the proposed AD--but Boeing Service Bulletin 747-
53A2303, Revision 2, dated October 1, 2009, specifies 500 flight cycles 
for paragraphs (l) and (m) of the proposed AD. Boeing stated that the 
preventive modifications include the protruding head fastener 
modification and the external reinforcement doubler installation (which 
does not cut the lap).
    We partially agree with the request. We agree that, as written, the 
compliance times specified in paragraphs (l) and (m) of the proposed AD 
(76 FR 38074, June 29, 2011) would have conflicted with the compliance 
time specified in paragraph (k) in the proposed AD, as described by the 
commenter. But, for airplanes nearing the 5,000-flight-cycle repetitive 
interval specified in paragraph (k) of the AD on the new effective 
date, removing paragraph (k) from the AD would allow an unwarranted 
extension of time to comply, and could compromise the continued safe 
operation of those airplanes. We have therefore retained paragraph (k) 
in this AD. We have further determined that, once the applicable 
inspections specified in paragraph (l) or (m) of the AD have been 
initiated, the actions in paragraph (k) are no longer necessary. To 
avoid the conflict described by the commenter, we have revised 
paragraphs (l) and (m) of this AD to state that their accomplishment 
terminates the requirements of paragraph (k) of this AD.

Request To Revise Modification Requirements

    Boeing requested that we revise paragraph (n) of the proposed AD 
(76 FR 38074, June 29, 2011) to specify separate requirements for the 
two groups of affected airplanes, so that the proposed AD agrees with 
the actions specified in Table 2 of paragraph 1.E., ``Compliance,'' of 
Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009.
    One group affected by paragraph (n) of the proposed AD (76 FR 
38074, June 29, 2011) is airplanes on which no previous modification or 
repair has been installed in the affected area. For those airplanes, 
Boeing requested that we require a structural modification in 
accordance with Part 3 of Boeing Service Bulletin 747-53A2303, Revision 
2, dated October 1, 2009, within the compliance time specified in 
paragraph A. of AD 90-06-06, Amendment 39-6490 (55 FR 8374, March 7, 
1990).
    (AD 90-06-06, Amendment 39-6490 (55 FR 8374, March 7, 1990), 
applies to certain Boeing Model 747 series airplanes and requires 
structural modifications in accordance with Boeing Document D6-35999, 
dated March 31, 1989. That document in turn refers to Boeing Alert 
Service Bulletin 747-53A2303, dated June 2, 1988, as another source of 
guidance for doing that modification.)
    Boeing requested no change for the remaining airplanes identified 
in paragraph (n) of the proposed AD (76 FR 38074, June 29, 2011).
    We partially agree. For the referenced airplanes, this same 
modification is one of the requirements of AD 90-06-06, Amendment 39-
6490 (55 FR 8374, March 7, 1990). The compliance time for this 
modification is 23,000 total accumulated flight cycles, or within 4 
years after the effective date (April 17, 1990), whichever occurs 
later. To clarify the ADs' requirements, we have removed those 
airplanes from paragraph (n) of the NPRM (76 FR 38074, June 29, 2011) 
and added a new paragraph (o) in this AD, which explains that, for 
those airplanes, accomplishment of the referenced modification 
satisfies the corresponding requirement for AD 90-06-06, but post-
modification inspections are required. We have re-identified subsequent 
paragraphs in this AD accordingly.

Request To Refer to Service Information for Compliance Data

    Boeing requested that the FAA review the compliance data in the 
proposed AD (76 FR 38074, June 29, 2011). Boeing noted that the 
proposed AD repeated all the compliance data as stated in Boeing 
Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009. Boeing 
requested that we refer to the compliance table in this service 
bulletin as the source of all compliance data, except as noted.
    Referring to paragraph 1.E., ``Compliance,'' of a service bulletin 
may be an efficient way to convey compliance time information in an AD, 
if the compliance times are complex or numerous. But specifying simpler 
compliance times within an AD--as in paragraphs (l), (m), and (n) in 
this AD--is also acceptable and enforceable. For requirements retained 
from a superseded AD--as in paragraphs (g) through (k) in this AD--we 
routinely restate the existing language from the AD that is being 
superseded, including the text describing the compliance times. We have 
not changed this AD regarding this issue.

Explanation of Additional Changes to This AD

    The information in Note 1 of the proposed AD (76 FR 38074, June 29, 
2011) has been moved to a new paragraph (g)(4) in this AD.
    As explained in the proposed AD (76 FR 38074, June 29, 2011), 
paragraph (p) in the proposed AD (paragraph (q) in this final rule) was 
revised to add delegation of authority to Boeing Commercial Airplanes 
Organization Designation Authorization (ODA) to approve an alternative 
method of compliance for any repair required by this AD. We have also 
changed paragraph (k) of this AD to reflect this change.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously and minor editorial 
changes. We have determined that these minor changes:
     Are consistent with the intent that was proposed in the 
NPRM (76 FR 38074, June 29, 2011) for correcting the unsafe condition; 
and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (76 FR 38074, June 29, 2011).
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of the AD.

Costs of Compliance

    There are about 165 airplanes of the affected design in the 
worldwide fleet; of these, 64 are U.S.-registered airplanes. The 
following table provides the estimated costs for U.S. operators to 
comply with this AD.

[[Page 29859]]



                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Average labor
               Action                        Work hours          rate per hour           Parts              Cost per airplane           Fleet cost
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection (required by AD 90-21-17,  8.......................             $85  $0.....................  $680 per inspection      $43,520 per inspection
 Amendment 39-6768 (55 FR 41510,                                                                          cycle.                   cycle.
 October 12, 1990).
Modification (new action)...........  Up to 370...............              85  Between $954 and $2,064  Up to $33,514..........  Up to $2,144,896.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition actions specified in this AD.

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 AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by removing airworthiness directive (AD) 
90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), and adding 
the following new AD:

2012-10-03 The Boeing Company: Amendment 39-17052; Docket No. FAA-
2011-0645; Directorate Identifier 2010-NM-009-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective June 25, 2012.

(b) Affected ADs

    This AD supersedes AD 90-21-17, Amendment 39-6768 (55 FR 41510, 
October 12, 1990).

(c) Applicability

    This AD applies to The Boeing Company Model 747-100, 747-100B, 
747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series 
airplanes, certificated in any category, as identified in Boeing 
Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by from reports of multiple adjacent cracks 
on an airplane, and a recent fleet-wide evaluation of widespread 
fatigue damage of skin lap joints, which indicated the need for 
revised procedures and reduced compliance times. The Federal 
Aviation Administration is issuing this AD to detect and correct 
cracking of the fuselage skin lap splice between body station (BS) 
400 and BS 520, at stringers S-6L and S-6R. Such cracking could 
result in sudden loss of cabin pressurization and the inability of 
the fuselage to withstand fail-safe loads.

(f) Compliance

    You are responsible for having the actions required by this AD 
performed within the compliance times specified, unless the actions 
have already been done.

(g) Retained Inspections

    This paragraph restates the requirements of paragraph A. of AD 
90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with 
revised service information, reduced inspection interval, and added 
subparagraph. Conduct a close visual or detailed inspection, and a 
high frequency eddy current (HFEC) inspection, of the fuselage skin 
lap splice between BS 400 and BS 520, at stringers S-6L and S-6R, 
for cracking, in accordance with Boeing Alert Service Bulletin 747-
53A2303, dated June 2, 1988, or Revision 1, dated March 29, 1990; or 
Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 
2009; at the times specified in paragraph (g)(1), (g)(2), or (g)(3) 
of this AD. After the effective date of this AD, only Boeing Service 
Bulletin 747-53A2303, Revision 2, dated October 1, 2009, may be 
used. Adequate lighting must be used for this inspection. The eddy 
current inspections may be conducted without removal of the paint, 
provided the paint does not interfere with the inspections. Paint 
must be removed, using an approved chemical stripper, in any 
situation where the inspector determines that the paint is 
interfering with the proper functioning of the inspection 
instrument.
    (1) Within the next 100 landings after March 31, 1989 (the 
effective date of AD 89-05-03, Amendment 39-6146 (54 FR 7397, 
February 21, 1989), which was superseded by AD 90-21-17, Amendment 
39-6768 (55 FR 41510, October 12, 1990)), for airplanes that have 
accumulated 16,000 or more landings as of March 31, 1989, unless 
previously accomplished within the last 4,900 landings.
    (2) Within the next 1,000 landings after March 31, 1989, or 
prior to the accumulation of 16,000 landings, whichever occurs 
first, for airplanes that have accumulated between 12,000 and 16,000 
landings, as of March 31, 1989 (the effective date of AD 89-05-03, 
Amendment 39-6146 (54 FR 7397, February 21, 1989), which was 
superseded by AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 
12, 1990)), unless previously accomplished within the last 4,000 
landings.
    (3) Prior to the accumulation of 13,000 landings for airplanes 
that have accumulated 12,000 or fewer landings as of March 31, 1989 
(the effective date of AD 89-05-03,

[[Page 29860]]

Amendment 39-6146 (54 FR 7397, February 21, 1989), which was 
superseded by AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 
12, 1990)), unless previously accomplished within the last 5,000 
landings.
    (4) 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 mirror, 
magnifying lenses, etc., may be necessary. Surface cleaning and 
elaborate procedures may be required.''

(h) Retained Inspection Compliance Time for SUD-Modified Airplanes

    This paragraph restates the requirements of paragraph B. of AD 
90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with 
revised service information. On airplanes which have been modified 
to the stretched-upper-deck configuration, as identified in Boeing 
Alert Service Bulletin 747-53A2303, dated June 2, 1988, or Revision 
1, dated March 29, 1990; or Boeing Service Bulletin 747-53A2303, 
Revision 2, dated October 1, 2009; the accumulated landing threshold 
for compliance with paragraph (g) of this AD is measured from the 
time of the stretched-upper-deck modification.

(i) Retained Repetitive Inspections

    This paragraph restates the requirements of paragraph C. of AD 
90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with 
revised service information. If no cracking is detected during the 
inspections required by paragraph (g) of this AD, repeat the 
inspections required by paragraph (g) of this AD one time at the 
earlier of the times specified in paragraphs (i)(1) and (i)(2) of 
this AD. Thereafter repeat the inspections at intervals not to 
exceed 3,000 landings.
    (1) Within 5,000 landings after the last inspection.
    (2) Within 3,000 landings after the last inspection, or within 
1,000 landings after the effective date of this AD, whichever occurs 
later.

(j) Retained Repair

    This paragraph restates the requirements of paragraph D. of AD 
90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with 
revised service information. If cracks are detected during the 
inspections required by paragraph (g) of this AD, accomplish the 
repair or preventive modification of the affected lap splice, in 
accordance with Boeing Alert Service Bulletin 747-53A2303, dated 
June 2, 1988, or Revision 1, dated March 29, 1990; or Boeing Service 
Bulletin 747-53A2303, Revision 2, dated October 1, 2009; prior to 
further pressurized flight. After the effective date of this AD, 
only Boeing Service Bulletin747-53A2303, Revision 2, dated October 
1, 2009, may be used. If cracks are repaired in local areas without 
accomplishing preventive modification of the entire affected lap 
area, continue inspections of the unmodified and unrepaired areas of 
the affected lap splice in accordance with paragraph (i) of this AD.

(k) Retained Inspection Compliance Time for Airplanes With Preventive 
Modification

    This paragraph restates the requirements of paragraph E. of AD 
90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with 
revised service information. For airplanes incorporating the 
preventive modification, as described in Boeing Alert Service 
Bulletin 747-53A2303, dated June 2, 1988, or Revision 1, dated March 
29, 1990; or Boeing Service Bulletin 747-53A2303, Revision 2, dated 
October 1, 2009; accomplish the inspections required by paragraph 
(g) of this AD prior to the accumulation of 10,000 landings after 
the modification and thereafter at intervals not to exceed 5,000 
landings. If cracks are found, repair using a method approved in 
accordance with the procedures specified in paragraph (q) of this 
AD, prior to further pressurized flight.

(l) New Requirement of This AD: Post-Modification Inspections

    For airplanes on which a protruding head fastener modification 
has been done in accordance with Boeing Alert Service Bulletin 747-
53A2303, dated June 2, 1988, or Revision 1, dated March 29, 1990: 
Within 10,000 flight cycles after modification, or within 500 flight 
cycles after the effective date of this AD, whichever occurs later, 
do an external HFEC inspection for cracking in the skin around the 
fasteners in the upper row of the lap joint, in accordance with Part 
5 of the Accomplishment Instructions of Boeing Service Bulletin 747-
53A2303, Revision 2, dated October 1, 2009. If any crack is found, 
before further flight repair in accordance with Boeing Service 
Bulletin 747-53A2303, Revision 2, dated October 1, 2009 (except as 
required by paragraph (p) of this AD), or do the modification 
specified in paragraph (n) of this AD. Repeat the inspection in 
affected uncracked areas at intervals not to exceed 500 flight 
cycles, until the modification specified in paragraph (n) of this AD 
is done. Accomplishment of the initial inspection and all applicable 
corrective actions specified in this paragraph terminates the 
requirements of paragraph (k) of this AD.

(m) New Requirement of This AD: Internal HFEC Inspection

    For airplanes on which an external doubler repair has been 
installed as a modification that was done using a method other than 
that specified in Boeing 747 structural repair manual (SRM) 53-30-
03, Figure 19, 25, 28 or 34: Within 10,000 flight cycles after 
modification, or within 500 flight cycles after the effective date 
of this AD, whichever occurs later, do an internal HFEC inspection 
for cracking in the skin around the fasteners in the upper row of 
the lap joint, in accordance with Part 5 of the Accomplishment 
Instructions of Boeing Service Bulletin 747-53A2303, Revision 2, 
dated October 1, 2009. If any crack is found, before further flight 
repair in accordance with Boeing Service Bulletin 747-53A2303, 
Revision 2, dated October 1, 2009 (except as required by paragraph 
(p) of this AD), or do the modification specified in paragraph (n) 
of this AD. Repeat the inspection in affected uncracked areas at 
intervals not to exceed 500 flight cycles, until the modification 
specified in paragraph (n) of this AD is done. Accomplishment of the 
initial inspection and all applicable corrective actions specified 
in this paragraph terminates the requirements of paragraph (k) of 
this AD.

(n) New Requirement of This AD: External Doubler Modification

    For airplanes on which a protruding head fastener modification 
or a Boeing 747 SRM 53-30-03 repair or modification has been 
installed that was not done using Boeing 747 SRM 53-30-03, Figure 
19, 25, 28, or 34, for the full length of the lap splice: Within 
14,000 flight cycles after the first repair or modification was 
done, or within 3,000 flight cycles after the effective date of this 
AD, whichever occurs later, modify the skin and do all post-
modification inspections and repairs, in accordance with Part 3 of 
the Accomplishment Instructions of Boeing Service Bulletin 747-
53A2303, Revision 2, dated October 1, 2009, except as required by 
paragraph (o) of this AD. Do the post-modification inspection within 
10,000 flight cycles after installation of the modification. Repeat 
the inspection thereafter at intervals not to exceed 3,000 flight 
cycles. All applicable repairs must be done before further flight.

(o) Structural Modification

    The provisions of paragraphs (o)(1) and (o)(2) of this AD apply 
to airplanes on which no previous modification or repair has been 
installed in the affected area.
    (1) Accomplishment of the structural modification specified in 
Part 3 of the Accomplishment Instructions of Boeing Service Bulletin 
747-53A2303, Revision 2, dated October 1, 2009, satisfies the 
requirements of AD 90-06-06, Amendment 39-6490 (55 FR 8374, March 7, 
1990), for only the corresponding modification specified in Boeing 
Alert Service Bulletin 747-53A2303, dated June 2, 1988, and Revision 
1, dated March 29, 1990; and Boeing Service Bulletin 747-53A2303, 
Revision 2, dated October 1, 2009.
    (2) After accomplishment of the modification specified in 
paragraph (o)(1) of this AD, the applicable requirements and 
compliance times of paragraphs (l) and (m) of this AD apply.

(p) Exception to Service Bulletin Specification

    Where Boeing Service Bulletin 747-53A2303, Revision 2, dated 
October 1, 2009, specifies to contact Boeing for appropriate action: 
Before further flight, repair using a method approved in accordance 
with the procedures specified in paragraph (q) of this AD.

(q) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly

[[Page 29861]]

to the manager of the ACO, send it to the attention of the person 
identified in the Related Information section of this AD. 
Information may be emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (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 the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) or other person 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 90-21-17, 
Amendment 39-6768 (55 FR 41510, October 12, 1990), are approved as 
AMOCs for the corresponding provisions of paragraphs (g) and (i) of 
this AD. AMOCs approved previously in accordance with AD 90-21-17, 
Amendment 39-6768 (55 FR 41510, October 12, 1990), are approved as 
AMOCs for the corresponding provisions of paragraphs (j) and (n) of 
this AD only if the repair or preventive modification of the 
affected lap splice was done in accordance with Boeing Service 
Bulletin 747-53A2303, Revision 2, dated October 1, 2009, including 
Boeing Designated Engineering Representative (DER) or Airworthiness 
Representative (AR) approvals of deviations to Boeing Service 
Bulletin 747-53A2303, Revision 2, dated October 1, 2009.

(r) Related Information

    For more information about this AD, contact Bill Ashforth, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office (ACO), 1601 Lind Avenue SW., Renton, Washington 
98057-3356; telephone 425-917-6432; fax 425-917-6590; email: 
[email protected].

(s) Material Incorporated by Reference

    (1) You must use the following service information to do the 
actions required by this AD, unless the AD specifies otherwise. The 
Director of the Federal Register approved the incorporation by 
reference (IBR) of the following service information under 5 U.S.C. 
552(a) and 1 CFR part 51:
    (i) Boeing Alert Service Bulletin 747-53A2303, dated June 2, 
1988.
    (ii) Boeing Alert Service Bulletin 747-53A2303, Revision 1, 
dated March 29, 1990.
    (iii) Boeing Service Bulletin 747-53A2303, Revision 2, dated 
October 1, 2009.
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 
206-544-5000, extension 1; fax 206-766-5680; email 
[email protected]; Internet https://www.myboeingfleet.com.
    (3) You may review copies of the service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, 
Washington. For information on the availability of this material at 
the FAA, call 425-227-1221.
    (4) You may also review copies of the service information that 
is incorporated by reference at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at an NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on May 8, 2012.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-11869 Filed 5-18-12; 8:45 am]
BILLING CODE 4910-13-P