Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 77, Number 69 (Tuesday, April 10, 2012)]
[Rules and Regulations]
[Pages 21426-21429]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-8232]


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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; 
Amendment 39-17013; AD 2012-07-07]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for all The 
Boeing Company Model 747 airplanes. 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. This AD 
requires 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. 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.

DATES: This AD is effective May 15, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of May 15, 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, WA 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: 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; email: [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That NPRM was published in the Federal Register on September 1, 2011 
(76 FR 54405). That NPRM proposed to 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.

[[Page 21427]]

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
and the FAA's response to each comment.

Request to Withdraw the NPRM (76 FR 54405, September 1, 2011)

    United Parcel Service (UPS) asked that we withdraw the NPRM (76 FR 
54405, September 1, 2011). UPS stated that there is a lack of 
justification for issuing the NPRM and added that it is being issued 
based on a report of a fatigue crack in the 17-4PH material latch pins 
of the lower cargo door, and the assumption that adjacent latch pins 
could also be affected. UPS noted that the latching structures of the 
lower forward and aft cargo door each include eight latch pins; those 
latch pins are part of a fail-safe design, which should preclude 
critical failure with the failure of one element. UPS added that the 
Model 747-400 maintenance planning document includes a detailed 
inspection of the latch mechanism of the lower cargo door, which 
includes the latch pins, at 2 year or 2,000 flight cycle intervals, 
whichever occurs first. UPS noted that the NPRM would require 
repetitive inspections at 1,600-flight-cycle intervals--a modest 
increase in frequency over the existing maintenance program--which has 
already been proven successful at detecting damage to adjacent latch 
pins. UPS concluded that, based on the extensive fleet history of the 
latch pins of these lower cargo doors, with no reports of adjacent pin 
failures, the existing maintenance program inspections of the latch 
pins are adequate.
    We do not agree with the commenter's request to withdraw the NPRM 
(76 FR 54405, September 1, 2011). Although the commenter has not 
experienced pin failure in service, the manufacturer has found pin 
fatigue failure on another airplane of the same type design. Therefore, 
we find we must issue this AD to address the identified unsafe 
condition on the entire fleet.
    The inspections identified in the maintenance planning document are 
general visual inspections of the entire door. The inspections required 
by this final rule include detailed inspections of the latch pins 
themselves. These detailed inspections are the result of the pin 
fracturing in service. The fractured pin was the number eight latch pin 
on the lower sill of the aft lower lobe cargo door; investigation by 
the manufacturer revealed that the crack initiated due to fatigue, and 
propagated by a combination of fatigue and stress corrosion. If the 
latch pins on the lower sill are not regularly inspected, and broken 
latch pins are not replaced, the forward and/or aft cargo door could 
open during service, resulting in loss of the cargo door, rapid 
decompression, and significant damage to the airplane. No change to the 
AD is necessary in this regard.

Request To Clarify Language in Relevant Service Information Section

    Boeing asked that the description specified in the ``Relevant 
Service Information'' section of the NPRM (76 FR 54405, September 1, 
2011) be changed as follows: ``The service bulletin describes 
procedures for repetitive detail inspections of latch pins 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 cracked, broken or missing latch pins; and corrective actions 
if necessary.'' Boeing stated that Boeing Alert Service Bulletin 747-
53A2835, dated October 28, 2010, necessitates that a detailed 
inspection be done on all pins (including previously replaced pins). 
Boeing added that the detailed inspection is for cracks, and the 
general visual inspection is to look for the broken and missing pins. 
Boeing notes that paragraph (g) of the NPRM provides the correct 
description of the inspections specified in the service bulletin.
    We acknowledge the commenter's concern and agree that the language 
could be clarified somewhat; however, since that section of the 
preamble does not reappear in the final rule, no change to this AD is 
necessary in this regard.

Request To Include Revision 1 of the Referenced Service Bulletin

    Boeing also asked that Boeing Alert Service Bulletin 747-53A2835, 
Revision 1, dated December 8, 2011, be included in the NPRM (76 FR 
54405, September 1, 2011) for accomplishing certain actions. Boeing 
Alert Service Bulletin 747-53A2835, dated October 28, 2010, was 
referred to as the appropriate source of service information for 
accomplishing the actions specified in the NPRM. Boeing added that 
Boeing Alert Service Bulletin 747-53A2835, Revision 1, dated December 
8, 2011, is scheduled for FAA-approval, and includes a latch pin 
modification and post-modification inspection to address the safety 
issue.
    We have reviewed Boeing Alert Service Bulletin 747-53A2835, 
Revision 1, dated December 8, 2011, and agree to include it in this 
final rule as an additional source of service information. Boeing Alert 
Service Bulletin 747-53A2835, Revision 1, dated December 8, 2011, 
reduces an existing compliance time, adds a latch pin modification, and 
repetitive post-modification inspections. We are including the actions 
in Boeing Alert Service Bulletin 747-53A2835, Revision 1, dated 
December 8, 2011, as optional in order to avoid delaying issuance of 
the AD. We have revised paragraph (g) of this AD accordingly. We are 
currently considering additional rulemaking to require the modification 
and post-modification inspections.

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:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM (76 FR 54405, September 1, 2011) for correcting the unsafe 
condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM (76 FR 54405, September 1, 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

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

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


[[Page 21428]]

    We estimate the following costs to do any necessary replacements/
modifications that would be required based on the results of the 
required 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

    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 adding the following new airworthiness 
directive (AD):

2012-07-07 The Boeing Company: Amendment 39-17013; Docket No. FAA-
2011-0915; Directorate Identifier 2011-NM-020-AD.

(a) Effective Date

    This AD is effective May 15, 2012.

(b) Affected ADs

    None.

(c) Applicability

    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.

(d) Subject

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

(e) Unsafe Condition

    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.

(f) Compliance

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

(g) Inspections

    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, dated October 28, 2010; 
or Boeing Alert Service Bulletin 747-53A2835, Revision 1, dated 
December 8, 2011. Repeat the inspections thereafter at the 
applicable intervals specified in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 747-53A2835, dated October 28, 2010; 
or Boeing Alert Service Bulletin 747-53A2835, Revision 1, dated 
December 8, 2011. Before further flight, do all applicable 
corrective actions, in accordance with paragraph 3.B., ``Work 
Instructions,'' of Boeing Alert Service Bulletin 747-53A2835, dated 
October 28, 2010; or Boeing Alert Service Bulletin 747-53A2835, 
Revision 1, dated December 8, 2011.

(h) Special Flight Permits

    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.

(i) 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 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 ODA that has been authorized by the 
Manager, Seattle

[[Page 21429]]

ACO, to make those findings. For a repair method to be approved, the 
repair must meet the certification basis of the airplane.

(j) Related Information

    For more information about this AD, 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; email: 
[email protected].

(k) Material Incorporated by Reference

    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) under 5 U.S.C. 552(a) and 1 CFR part 51 of the following 
service information.
    (1) Boeing Alert Service Bulletin 747-53A2835, dated October 28, 
2010.
    (2) Boeing Alert Service Bulletin 747-53A2835, Revision 1, dated 
December 8, 2011.
    (3) 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; email [email protected]; 
Internet https://www.myboeingfleet.com.
    (4) 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.
    (5) 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 NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on March 28, 2012.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-8232 Filed 4-9-12; 8:45 am]
BILLING CODE 4910-13-P

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