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[Federal Register Volume 78, Number 191 (Wednesday, October 2, 2013)]
[Proposed Rules]
[Pages 60807-60809]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-24121]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0837; Directorate Identifier 2013-NM-112-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company 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 
certain The Boeing Company Model 737-200, -200C, -300, -400, and -500 
series airplanes. This proposed AD was prompted by reports of cracking 
found in the skin at the lower aft corner of the forward entry doorway 
on airplanes that do not have an airstair door cutout. This proposed AD 
would require repetitive inspections for cracking in the lower corners 
of the forward entry doorway on airplanes that do not have an airstair 
door cutout, and repair if necessary. We are proposing this AD to 
detect and correct cracking in the lower corners of the forward entry 
doorway, which could lead to crack progression and consequent rapid 
decompression of the airplane.

DATES: We must receive comments on this proposed AD by November 18, 
2013.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, 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: 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; 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, WA. 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: Alan Pohl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue SW., Renton, WA 98057-3356; phone: (425) 917-6450; 
fax: (425) 917-6590; email: alan.pohl@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-2013-0837; 
Directorate Identifier 2013-NM-112-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy

[[Page 60808]]

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 five reports of cracking found in the skin at the 
lower aft corner of the forward entry doorway on airplanes that do not 
have an airstair door cutout. The cracks ranged from 0.25 to 2.0 inches 
in length. The airplanes had accumulated between 34,813 and 73,083 
total flight cycles. Cracking in the lower corners of the forward entry 
doorway is caused by fatigue loads in the skin and bear strap, and are 
magnified by local stress concentrations due to the door cutout and 
edge margin effects at fastener locations near the corner radius. 
Cracking can also be initiated from impact damage due to a high usage 
rate of the forward entry door. This condition, if not corrected, could 
result in crack progression and consequent rapid decompression of the 
airplane.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin 737-53A1329, dated June 
4, 2013. This service bulletin describes procedures for repetitive 
inspections for cracking in the skin assembly and bear strap at the 
lower corners of the forward entry doorway. This service bulletin 
describes the following actions:
     Internal detailed inspection of the skin assembly and bear 
strap;
     Internal high frequency eddy current (HFEC) inspection of 
the bear strap;
     External detailed and HFEC inspections of the skin 
assembly; and,
     Contacting Boeing for inspection (for Group 1 airplanes), 
inspection (for Groups 2 and 3 airplanes), and crack repair 
instructions (Group 3 airplanes).
    Boeing Alert Service Bulletin 737-53A1329, dated June 4, 2013, 
specifies compliance times for the initial inspection as before the 
accumulation of 27,000 total flight cycles or within 4,500 flight 
cycles after the issue date of the service bulletin, whichever occurs 
later. The repetitive interval is 4,500 flight cycles. Repairs are to 
be done before further flight.

Other Relevant Rulemaking

    For The Boeing Company Model 737-300, -400, and -500 series 
airplanes, the repair identified in Boeing Alert Service Bulletin 737-
53A1329, dated June 4, 2013, may affect certain areas of Significant 
Structural Item F-13A inspections required by paragraphs (g) and (h) of 
AD 2008-09-13, Amendment 39-15494 (73 FR 24164, May 2, 2008).

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 the same type design.

Proposed AD Requirements

    This proposed AD would require accomplishing the actions specified 
in the service information described previously, except as discussed 
under ``Differences Between this Proposed AD and the Service 
Information.''

Differences Between This Proposed AD and the Service Information

    Boeing Alert Service Bulletin 737-53A1329, dated June 4, 2013, 
specifies contacting the manufacturer for inspection instructions (for 
Group 1 airplanes) and for repair instructions (all airplanes), but 
this proposed AD would require accomplishing those actions in one of 
the following ways:
     In accordance with a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by the Boeing Commercial 
Airplanes Organization Designation Authorization whom we have 
authorized to make those findings.
    This difference has been coordinated with Boeing.

Costs of Compliance

    We estimate that this proposed AD affects 376 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspection of the lower corners    5 work-hours x $85               $0  $425, per            $159,800, per
 of the forward entry doorway       per hour = $425,                     inspection cycle.    inspection cycle.
 (Groups 2 and 3 airplanes) \1\.    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------
\1\ We have received no definitive data that would enable us to provide cost estimates for the inspection on
  Group 1 airplanes.

    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition actions specified in this proposed 
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

    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

[[Page 60809]]

    (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

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):

The Boeing Company: Docket No. FAA-2013-0837; Directorate Identifier 
2013-NM-112-AD.

(a) Comments Due Date

    We must receive comments by November 18, 2013.

(b) Affected ADs

    For The Boeing Company Model 737-300, -400, and -500 series 
airplanes: Certain requirements of AD 2008-09-13, Amendment 39-15494 
(73 FR 24164, May 2, 2008), may be affected by certain requirements 
of this AD.

(c) Applicability

    This AD applies to The Boeing Company Model 737-200, -200C, -
300, -400, and -500 series airplanes, certificated in any category, 
without an airstair door cutout, as identified in Boeing Alert 
Service Bulletin 737-53A1329, dated June 4, 2013.

(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 cracking found in the skin at 
the lower aft corner of the forward entry doorway on airplanes that 
do not have an airstair door cutout. We are issuing this AD to 
detect and correct cracking in the lower corners of the forward 
entry doorway, which could lead to crack progression and consequent 
rapid decompression of the airplane.

(f) Compliance

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

(g) Repetitive Inspections

    Except as provided by paragraph (i)(1) of this AD, at the 
applicable times specified in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 737-53A1329, dated June 4, 2013, do 
the actions specified in paragraph (g)(1) or (g)(2) of this AD, as 
applicable.
    (1) For Group 1 airplanes, as identified in Boeing Alert Service 
Bulletin 737-53A1329, dated June 4, 2013: Except as provided by 
paragraph (i)(2) of this AD, inspect the lower corners of the 
forward entry doorway for cracking, using a method approved in 
accordance with the procedures specified in paragraph (j) of this 
AD.
    (2) For Group 2 and Group 3 airplanes, as identified in Boeing 
Alert Service Bulletin 737-53A1329, dated June 4, 2013: At the 
forward entry doorway lower forward and aft corners, as applicable, 
do an internal detailed inspection of the skin assembly and bear 
strap, an internal high frequency eddy current (HFEC) inspection of 
the bear strap, and external detailed and HFEC inspections of the 
skin assembly for cracking, in accordance with Part 2 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1329, dated June 4, 2013. If no cracking is found during any 
inspection required by this paragraph: Except as provided by 
paragraph (i)(1) of this AD, repeat the applicable inspections at 
the applicable time specified in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 737-53A1329, dated June 4, 2013.

(h) Repair

    (1) If any cracking is found during any inspection required by 
paragraph (g) of this AD: For Group 3 airplanes with cracking at the 
aft lower corner of the forward entry doorway, before further 
flight, repair in accordance with Part 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1329, dated 
June 4, 2013. Accomplishment of this repair terminates the 
repetitive inspections required by this AD in the area common to the 
repair for Group 3 airplanes only. For all other cracking found, 
before further flight, repair using a method approved in accordance 
with the procedures specified in paragraph (j) of this AD.
    (2) Installation of a repair approved in accordance with 
paragraph (j) of this AD terminates the repetitive inspections 
required by this AD for the repaired area only.

(i) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 737-53A1329, dated June 
4, 2013, specifies a compliance time ``after the original issue date 
of this service bulletin,'' this AD requires compliance within the 
specified compliance time after the effective date of this AD.
    (2) Although Boeing Alert Service Bulletin 737-53A1329, dated 
June 4, 2013, specifies contacting Boeing for information on certain 
inspections and repairs, this AD requires that those actions be done 
by using a method approved in accordance with the procedures 
specified in paragraph (j) of this AD.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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: 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 Organization Designation Authorization 
(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, and the approval must 
specifically refer to this AD.

(k) Related Information

    (1) For more information about this AD, contact Alan Pohl, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; 
phone: (425) 917-6450; fax: (425) 917-6590; email: 
alan.pohl@faa.gov.
    (2) 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; 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, WA. For information on the availability of 
this material at the FAA, call 425-227-1221.

    Issued in Renton, Washington, on September 25, 2013.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-24121 Filed 10-1-13; 8:45 am]
BILLING CODE 4910-13-P
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