

[Federal Register: October 17, 2007 (Volume 72, Number 200)]
[Proposed Rules]               
[Page 58768-58770]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr17oc07-13]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0045; Directorate Identifier 2007-NM-169- AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 747-200F, 747-300, 747-
400, and 747-400D Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Boeing Model 747-200F, 747-300, 747-400, and 747-400D 
series airplanes. This proposed AD would require a detailed inspection 
to detect missing fasteners from the shear clip at a certain stub frame 
to auxiliary sill joint, and applicable related investigative and 
corrective actions. This proposed AD results from reports of missing 
fasteners from the shear clip of the stub frame to auxiliary sill joint 
and cracking of the adjacent exterior skin and internal doubler. We are 
proposing this AD to ensure that fasteners are installed in the shear 
clip of the stub frame to auxiliary sill joint. Missing fasteners could 
result in cracks in the adjacent exterior skin and internal doubler, 
which can propagate and result in loss of structural integrity and 
sudden in-flight decompression of the airplane.

DATES: We must receive comments on this proposed AD by December 3, 
2007.

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.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

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 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-2007-0045; 
Directorate Identifier 2007-NM-169-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 proposed 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 proposed AD.

Discussion

    We have received two reports of cracks found in the exterior skin 
and internal doubler adjacent to the shear clip at the stub frame to 
auxiliary sill joint at stringer 30 (left and right sides), body 
station (BS) 488. In addition, on one of the airplanes, seven fasteners 
were missing from the shear clip on the left side of the airplane. The 
cause of the missing fasteners has been attributed to a manufacturing 
process error. If any fastener is missing from the shear clip at the 
stub frame to auxiliary sill joint, cracks could result in the exterior 
skin and internal doubler. Such cracks can propagate and result in loss 
of structural integrity and sudden in-flight decompression of the 
airplane.

[[Page 58769]]

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-53A2685, dated 
May 31, 2007. The service bulletin describes procedures for doing a 
detailed inspection to detect missing fasteners from the shear clip at 
the stub frame to auxiliary sill joint at stringer 30 (left and right 
sides), BS 488, and applicable related investigative and corrective 
actions. The related investigative actions include doing an open hole 
high frequency eddy current inspection to detect cracks at certain 
fastener locations in the exterior skin and internal doubler, and 
repetitive low frequency eddy current inspections to detect cracks at 
the edge row fasteners of any skin repair doubler, as applicable. The 
corrective actions include trimming out cracks, installing missing 
fasteners, installing skin repair doublers, and contacting Boeing for 
certain repair conditions, as applicable.
    The service bulletin also specifies the following compliance times:
     For the initial detailed inspection: Before 6,000 total 
flight cycles, or within 3,000 flight cycles, whichever occurs later.
     For the related investigative actions: Before further 
flight (for an open hole high frequency eddy current inspection), and 
within 15,000 flight cycles after installation of repair and thereafter 
at intervals not to exceed 1,500 flight cycles (for low frequency eddy 
current inspections).
     For the corrective actions: Before further flight.
    Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously, except as discussed under 
``Differences Between the Proposed AD and Service Information.''

Differences Between the Proposed AD and Service Information

    The service bulletin 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.

Costs of Compliance

    There are about 98 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 8 airplanes of 
U.S. registry. The proposed actions would take about 1 work hour per 
airplane, at an average labor rate of $80 per work hour. Based on these 
figures, the estimated cost of the proposed AD for U.S. operators is 
$640, or $80 per airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that the proposed 
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); and
    3. Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket. See the 
ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

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

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


Sec.  39.13  [Amended]

    2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-0045; Directorate Identifier 2007-NM-
169-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by December 
3, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 747-200F, 747-300, 747-400, 
and 747-400D series airplanes, certificated in any category; as 
identified in Boeing Alert Service Bulletin 747-53A2685, dated May 
31, 2007.

Unsafe Condition

    (d) This AD results from two reports of cracks found in the 
exterior skin and internal doubler adjacent to the shear clip at the 
stub frame to auxiliary sill joint at stringer 30 (left and right 
sides), body station (BS) 488. In addition, on one of the airplanes, 
seven fasteners were missing from the shear clip on the left side of 
the airplane. The cause of the missing fasteners has been attributed 
to a manufacturing process error. We are issuing this AD to ensure 
fasteners in the shear clip of the stub frame to auxiliary sill 
joints (left and right sides) are installed. Missing fasteners could 
result in cracks in the exterior skin and internal doubler, which 
can propagate and result in loss of structural integrity and sudden 
in-flight decompression of the airplane.

Compliance

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

[[Page 58770]]

Inspection and Applicable Related Investigative and Corrective Actions

    (f) At the applicable compliance time and repeat intervals 
listed in Tables 1 and 2 of paragraph 1.E., ``Compliance,'' of 
Boeing Service Bulletin 747-53A2685, dated May 31, 2007; except that 
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: Do 
the inspection and applicable related investigative and corrective 
actions by accomplishing all the applicable actions specified in the 
Accomplishment Instructions of the service bulletin, except as 
provided by paragraph (g) of this AD.

Repair of Cracks

    (g) If any crack is found during any inspection required by this 
AD, and Boeing Service Bulletin 747-53A2685, dated May 31, 2007, 
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 (h) of this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane, and the approval must specifically refer to this 
AD.

    Issued in Renton, Washington, on October 9, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-20467 Filed 10-16-07; 8:45 am]

BILLING CODE 4910-13-P
