[Federal Register Volume 73, Number 98 (Tuesday, May 20, 2008)]
[Rules and Regulations]
[Pages 29042-29044]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-11330]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0554; Directorate Identifier 2008-NM-100-AD; 
Amendment 39-15522; AD 2008-10-15]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 
747SR, and 747SP series airplanes. This AD 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, this AD 
requires repetitive related investigative actions and corrective 
actions if necessary. This AD also provides an optional terminating 
modification for the repetitive related investigative actions. This AD 
results from a report of cracked fastener holes at the right S-6 lap 
splice between STA 340 and STA 380. We are issuing this AD to detect 
and correct cracking in the fuselage skin, which could result in rapid 
decompression and loss of structural integrity.

DATES: This AD is effective May 20, 2008.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of May 20, 
2008.
    We must receive comments on this AD by July 21, 2008.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://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 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 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:

Discussion

    We have received a report of cracking found at fourteen adjacent 
fastener holes where protruding head fasteners were installed in the 
upper row of the right stringer 6 (S-6) lap splice, between station 
(STA) 360 and STA 380. The airplane had accumulated 23,132 total

[[Page 29043]]

flight cycles. The protruding head fasteners had been installed without 
external skin doublers 9,757 flight cycles earlier as one of several 
modification options provided in Boeing Service Bulletin 747-53-2253 
(AD 90-06-06, amendment 39-6490 (55 FR 8374, March 7, 1990), requires 
that one of the modifications specified in the service bulletin be 
done). Analysis by Boeing indicates that the protruding head fastener 
modification and the post-modification inspections are not adequate to 
prevent and detect cracks at the upper row of fasteners in the S-6 lap 
splices before the cracks reach critical length. The post-modification 
inspections are given in Boeing Service Bulletin 747-53-2253 and are 
required by AD 90-23-14, amendment 39-6801 (55 FR 46652, November 6, 
1990). Cracking in the fuselage skin, if not corrected, could result in 
rapid decompression and loss of structural integrity.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin 747-53A2748, dated May 9, 
2008. The alert service bulletin describes procedures for an external 
inspection to determine if acceptable external skin doublers are 
installed at the left- and right-side S-6 lap splices, between STA 340 
and STA 400. For airplanes without the acceptable external skin 
doublers, the alert service bulletin specifies doing repetitive related 
investigative actions and corrective actions if necessary. Related 
investigative actions include external high frequency eddy current 
(HFEC) and low frequency eddy current (LFEC) inspections of the skin 
for cracking, as applicable. Corrective actions include repairing 
cracking and repeating related investigative actions, or modifying the 
airplane by installing acceptable external skin doublers at both the 
left- and right-side S-6 lap splices (includes doing an open-hole HFEC 
inspection of the skin for cracking, and trimming out cracking if 
necessary). Doing the modification would end the repetitive related 
investigative actions.
    Boeing Alert Service Bulletin 747-53A2748 refers to Boeing Service 
Bulletin 747-53-2253, Revision 3, dated March 24, 1994; and Boeing 
Service Bulletin 747-53-2272, Revision 18, dated May 16, 2002; as 
additional sources of service information for accomplishment of the 
modification (installation of acceptable external skin doublers).

FAA's Determination and Requirements of This AD

    We are issuing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
This AD requires an external inspection to determine if acceptable 
external skin doublers are installed at the S-6 lap splices, between 
STA 340 and STA 400. For airplanes without the acceptable external skin 
doublers, this AD requires repetitive related investigative actions, as 
applicable, and corrective actions if necessary. This AD also provides 
an optional terminating modification for the repetitive related 
investigative actions.

Interim Action

    We consider this AD interim action. We are currently considering 
requiring the modification (installation of acceptable external skin 
doublers), which would terminate the repetitive related investigative 
actions. However, the planned compliance time for the modification 
would allow enough time to provide notice and opportunity for prior 
public comment on the merits of the modification.

FAA's Justification and Determination of the Effective Date

    We have determined that cracking of multiple adjacent fastener 
holes at the S-6 lap splices adjacent to the flight deck windows could 
join together and result in large cracks. Considering the number of 
accumulated flight cycles on the affected Boeing Model 747 airplanes 
and the consequences of cracking, we have determined that immediate 
inspections are necessary. Because of our requirement to promote safe 
flight of civil aircraft and thus, the critical need to assure the 
structural integrity of the fuselage and the short compliance time 
involved with this action, this AD must be issued immediately.
    Because an unsafe condition exists that requires the immediate 
adoption of this AD, we find that notice and opportunity for prior 
public comment hereon are impracticable and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety, and we did not provide you with notice and an opportunity to 
provide your comments before it becomes effective. However, we invite 
you to send any written data, views, or arguments about this AD. Send 
your comments to an address listed under the ADDRESSES section. Include 
``Docket No. FAA-2008-0554; Directorate Identifier 2008-NM-100-AD'' at 
the beginning of your comments. We specifically invite comments on the 
overall regulatory, economic, environmental, and energy aspects of this 
AD. We will consider all comments received by the closing date and may 
amend this AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about 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

    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), 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

[[Page 29044]]

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the 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 adding the following new AD:

2008-10-15 Boeing: Amendment 39-15522. Docket No. FAA-2008-0554; 
Directorate Identifier 2008-NM-100-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective May 20, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing 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 Alert Service 
Bulletin 747-53A2748, dated May 9, 2008.

Unsafe Condition

    (d) This AD results from a report of cracked fastener holes at 
the right stringer 6 (S-6) lap splice between station (STA) 340 and 
STA 380. We are issuing this AD to detect and correct cracking in 
the fuselage skin, which could result in rapid decompression and 
loss of structural integrity.

Compliance

    (e) Comply with this AD within the compliance times specified, 
unless already done.

Service Bulletin Reference Paragraph

    (f) The term ``alert service bulletin,'' as used in this AD, 
means the Accomplishment Instructions of Boeing Alert Service 
Bulletin 747-53A2748, dated May 9, 2008.

Inspection for Acceptable External Skin Doublers

    (g) For airplanes identified as Group 1, Configuration 2, in 
Boeing Alert Service Bulletin 747-53A2748, dated May 9, 2008: At the 
latest of the times specified in paragraphs (g)(1), (g)(2), and 
(g)(3) of this AD, do an external general visual inspection to 
determine if acceptable external skin doublers are installed at the 
left- and right-side S-6 lap splices, in accordance with Part 1 of 
the alert service bulletin.
    (1) Prior to the accumulation of 10,000 total flight cycles.
    (2) Within 8,000 flight cycles after a modification was done in 
accordance with Boeing Service Bulletin 747-53-2253.
    (3) Within 15 days or 100 flight cycles after the effective date 
of this AD, whichever occurs first.

Acceptable External Skin Doublers Found at Both Sides

    (h) If, during the inspection required by paragraph (g) of this 
AD, acceptable external skin doublers in accordance with the alert 
service bulletin are found installed at both the left- and right-
side S-6 lap splices, no further work is required by this AD.

Acceptable External Skin Doublers Not Found--Repetitive Related 
Investigative Actions and Corrective Actions

    (i) If, during the inspection required by paragraph (g) of this 
AD, acceptable external skin doublers in accordance with alert 
service bulletin are not found installed at either the left- or 
right-side S-6 lap splice: Before further flight, do all applicable 
related investigative and corrective actions by doing all actions 
specified in Part 2 of the alert service bulletin. Repeat the 
applicable related investigative actions thereafter at intervals not 
to exceed 300 flight cycles until the modification specified in 
paragraph (j) of this AD is done.

Optional Terminating Modification

    (j) Modifying the airplane by installing acceptable external 
skin doublers at both the left- and right-side S-6 lap splices 
(including doing an open-hole HFEC inspection of the skin for 
cracking, and trimming out cracking as applicable) in accordance 
with the alert service bulletin terminates the repetitive related 
investigative actions required by this AD.

    Note 1: The alert service bulletin refers to Boeing Service 
Bulletins 747-53-2253, Revision 3, dated March 24, 1994; and 747-53-
2272, Revision 18, dated May 16, 2002; as additional sources of 
service information for accomplishment of the modification 
(installation of acceptable external skin doublers).


    Note 2: AD 90-06-06, amendment 39-6490, requires, among other 
actions, one of the modification options specified in Boeing Service 
Bulletin 747-53-2253, dated December 14, 1984.


    Note 3: AD 90-23-14, amendment 39-6801, requires that 
inspections of modifications done in accordance with Boeing Service 
Bulletin 747-53-2253, and applicable repairs, be done in accordance 
with Boeing Service Bulletin 747-53-2253, Revision 2, dated March 
29, 1990.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle Aircraft Certification Office, FAA, 
ATTN: 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; 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.

Material Incorporated by Reference

    (l) You must use Boeing Alert Service Bulletin 747-53A2748, 
dated May 9, 2008, to do the actions required by this AD, unless the 
AD specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of this service information under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 
98124-2207.
    (3) You may review copies of the service information 
incorporated by reference at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the 
National Archives and Records Administration (NARA). For information 
on the availability of this material at NARA, call 202-741-6030, or 
go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on May 13, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-11330 Filed 5-19-08; 8:45 am]
BILLING CODE 4910-13-P