
[Federal Register Volume 76, Number 170 (Thursday, September 1, 2011)]
[Proposed Rules]
[Pages 54405-54408]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-22371]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0915; Directorate Identifier 2011-NM-020-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 747 Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above. This proposed AD would require repetitive 
general visual inspections for broken or missing latch pins of the 
lower sills of the forward and aft lower lobe cargo doors; repetitive 
detailed inspections for cracking of the latch pins; and corrective 
actions if necessary. This proposed AD was prompted by reports of 
fractured latch pins found in service; investigation revealed that the 
cracking and subsequent fracture were initiated by fatigue and 
propagated by a combination of fatigue and stress corrosion. We are 
proposing this AD to detect and correct fractured or broken latch pins, 
which could result in a forward or aft lower lobe cargo door opening 
and detaching during flight, and consequent rapid decompression of the 
airplane.

DATES: We must receive comments on this proposed AD by October 17, 
2011.

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.

[[Page 54406]]

     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: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; 
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 proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES 
section. Comments will be available in the AD docket shortly after 
receipt.

FOR FURTHER INFORMATION CONTACT: Nathan Weigand, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; phone: (425) 917-
6428; fax: (425) 917-6590; e-mail: nathan.p.weigand@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2011-0915; 
Directorate Identifier 2011-NM-020-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 reports of fractured latch pins found in service; 
investigation revealed that the cracking and subsequent fracture were 
initiated by fatigue and propagated by a combination of fatigue and 
stress corrosion. One operator reported a fractured latch pin of the 
lower sill of the aft lower lobe cargo door; the fracture initiated 
from a crack on the pin's internal diameter. Part of the pin was found 
on the ground during an airplane walk-around. The airplane had 
accumulated 75,495 total flight hours and 9,393 total flight cycles. A 
dye penetrant inspection of the remaining seven latch pins in the lower 
sill was done with no defects found. This condition, if not corrected, 
could result in a forward or aft lower lobe cargo door opening and 
detaching during flight, and consequent rapid decompression of the 
airplane.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin 747-53A2835, original, 
dated October 28, 2010. The service information describes procedures 
for repetitive general visual inspections for broken or missing latch 
pins of the lower sills of the forward and aft lower lobe cargo doors; 
repetitive detailed inspections of the replaced latch pins for broken 
or missing latch pins; and corrective actions if necessary.
    For Groups 1 and 2 airplanes, Configurations 1 and 2; and for Group 
3 airplanes; the corrective actions include replacing any broken or 
missing latch pin, and the latch pins at the adjacent latch fitting 
locations, with new latch pins; and replacing any cracked latch pins 
with new latch pins.
    For Group 1 airplanes, Configurations 3 and 4, there are two 
options for corrective actions:
     Replacing any broken or missing latch pin, and the latch 
pins at the adjacent latch fitting locations, with new latch pins (with 
identical part numbers); and replacing any cracked latch pins with new 
latch pins (with identical part numbers).
     Modifying or replacing the latch pins and bearing plates; 
replacing any broken or missing latch pin, and the latch pins at the 
adjacent latch fitting locations, with new latch pins (with alternative 
part numbers); and replacing any cracked latch pins with new latch pins 
(with alternative part numbers).
    For airplanes on which all latch pins are replaced, the first 
repetitive inspection interval is within 6,000 flight cycles after 
replacement. For airplanes on which not all of the latch pins are 
replaced, the first repetitive inspection interval is 1,600 flight 
cycles after inspecting. For all airplanes, the repetitive interval for 
subsequent inspections is 1,600 flight cycles.

FAA's Determination

    We are proposing 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 these same type 
designs.

Proposed AD Requirements

    This proposed AD would require accomplishing the actions specified 
in the service information described previously.

Interim Action

    We consider this proposed AD interim action. The manufacturer is 
currently developing a modification that will address the unsafe 
condition identified in this AD. Once this modification is developed, 
approved, and available, we might consider additional rulemaking.

Costs of Compliance

    We estimate that this proposed AD affects 228 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
           Action                  Labor cost         Parts cost     Cost per product     Cost on U.S. operators
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Inspection.................  3 work-hours x $85 per           $0  $255 per inspection     $58,140 per inspection
                              hour = $255 per                      cycle.                  cycle.
                              inspection cycle.
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[[Page 54407]]

    We estimate the following costs to do any necessary replacements/
modifications that would be required based on the results of the 
proposed inspection. We have no way of determining the number of 
aircraft that might need these actions:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                       Cost per
                   Action                                    Labor cost                  Parts cost    product
----------------------------------------------------------------------------------------------------------------
Replacement of latch pins...................  8 work-hours x $85 per hour = $680......           $0         $680
Modification of latch fittings..............  36 hours x $85 per work-hours = $3,060..            0        3,060
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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 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 this 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),
    (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.

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 FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2011-0915; Directorate Identifier 
2011-NM-020-AD.

Comments Due Date

    (a) We must receive comments by October 17, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all The Boeing Company 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.

Subject

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

Unsafe Condition

    (e) This AD was prompted by reports of fractured latch pins 
found in service; investigation revealed that the cracking and 
subsequent fracture were initiated by fatigue and propagated by a 
combination of fatigue and stress corrosion. We are issuing this AD 
to detect and correct fractured or broken latch pins, which could 
result in a forward or aft lower lobe cargo door opening and 
detaching during flight, and consequent rapid decompression of the 
airplane.

Compliance

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

Inspections

    (g) Before the accumulation of 6,000 total flight cycles, or 
within 1,000 flight cycles after the effective date of this AD, 
whichever occurs later: Do a general visual inspection for broken or 
missing latch pins of the lower sills of the forward and aft lower 
lobe cargo doors, and a detailed inspection for cracking of the 
latch pins, in accordance with paragraph 3.B., ``Work 
Instructions,'' of Boeing Alert Service Bulletin 747-53A2835, 
original, dated October 28, 2010. Repeat the inspections thereafter 
at the applicable intervals specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 747-53A2835, 
original, dated October 28, 2010. Before further flight, do all 
applicable corrective actions, in accordance with paragraph 3.B., 
``Work Instructions,'' of Boeing Alert Service Bulletin 747-53A2835, 
original, dated October 28, 2010.

Special Flight Permits

    (h) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the airplane can be modified (if the operator elects to do so), 
provided the cabin is not pressurized.

Alternative Methods of Compliance (AMOCs)

    (i)(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 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 e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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 ODA that 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.

Related Information

    (j) For more information about this AD, contact Nathan Weigand, 
Aerospace

[[Page 54408]]

Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 
98057-3356; phone: (425) 917-6428; fax: (425) 917-6590; e-mail: 
nathan.p.weigand@faa.gov.
    (k) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; 
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.

    Issued in Renton, Washington, on August 25, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-22371 Filed 8-31-11; 8:45 am]
BILLING CODE 4910-13-P


