[Federal Register: May 20, 2008 (Volume 73, Number 98)]
[Rules and Regulations]
[Page 29042-29044]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr20my08-2]
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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