
[Federal Register Volume 76, Number 96 (Wednesday, May 18, 2011)]
[Rules and Regulations]
[Pages 28632-28635]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-11928]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0348; Directorate Identifier 2011-NM-069-AD; 
Amendment 39-16701; AD 2011-08-51]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 737-300, -400, 
and -500 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for the 
products listed above. This emergency AD was sent previously to all 
known U.S. owners and operators of these airplanes. This AD requires 
repetitive external eddy current inspections of the lap joints at 
stringers S-4R and S-4L, along the entire length from body station (BS) 
360 to BS 908. If a crack indication is found, the AD requires either 
confirming the crack by doing internal eddy current inspections, or 
repairing the crack. As an alternative to the external eddy current 
inspections, the AD provides for internal eddy current and detailed 
inspections for cracks in the lower skin at the lower row of fasteners 
at stringers S-4L and S-4R. This AD was prompted by a report indicating 
that a Model 737-300 series airplane experienced a rapid decompression 
when the lap joint at stringer S-4L between BS 664 and BS 727 cracked 
and opened up due to cracking in the lower skin at the lower row of 
fasteners. We are issuing this AD to detect and correct such cracking, 
which could result in an uncontrolled decompression of the airplane.

DATES: This AD is effective June 2, 2011 to all persons except those 
persons to whom it was made immediately effective by Emergency AD 2011-
08-51, issued on April 5, 2011, which contained the requirements of 
this amendment.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications identified in the AD as of June 2, 
2011.
    We must receive comments on this AD by July 5, 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.
     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 AD, contact Boeing 
Commercial Airplanes, Attention: Data & Services Management, P.O. Box 
3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, 
extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet 
https://www.myboeingfleet.com.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations Office 
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 Operations 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: Wayne Lockett, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue, SW., Renton, Washington 98057-3356; phone: 
425-917-6447; fax: 425-917-6590; e-mail: wayne.lockett@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    On April 5, 2011, we issued Emergency AD 2011-08-51, which requires 
repetitive external eddy current inspections of the lap joints at 
stringers S-4R and S-4L, along the entire length from body station (BS) 
360 to BS 908. If a crack indication is found, the AD requires either 
confirming the crack by doing internal eddy current inspections, or 
repairing the crack. As an alternative to the external eddy current 
inspections, the AD provides for internal eddy current and detailed 
inspections for cracks in the lower skin at the lower row of fasteners 
at stringers S-4L and S-4R. This action was prompted by a report 
indicating that a Model 737-300 series airplane experienced a rapid 
decompression when the lap joint at stringer S-4L between BS 664 and BS 
727 cracked and opened up due to cracking in the lower skin at the 
lower row of fasteners. The airplane had accumulated 39,781 total 
flight cycles

[[Page 28633]]

and 48,740 total flight hours. Such cracking, if not corrected, could 
result in an uncontrolled decompression of the airplane.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin 737-53A1319, dated April 
4, 2011. That service bulletin describes procedures for external eddy 
current inspections of the lap joints at stringers S-4R and S-4L, along 
the entire length from BS 360 to BS 908. If a crack indication is 
found, that service bulletin specifies either confirming the crack by 
doing internal eddy current inspections, or repairing the crack. As an 
alternative to the external eddy current inspections, that service 
bulletin provides procedures for internal eddy current and detailed 
inspections for cracks in the lower skin at the lower row of fasteners 
at stringers S-4L and S-4R. That service bulletin specifies contacting 
Boeing for crack repair instructions.
    Since we issued the emergency AD, we have approved Revision 1 of 
this service bulletin as an alternative method of compliance (AMOC) 
with certain requirements of emergency AD 2011-08-51. We have added 
paragraph (l)(4) to this AD to provide information on this approved 
AMOC.

FAA's Determination

    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 these same type 
designs.

AD Requirements

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

Differences Between the AD and the Service Information

    That service bulletin specifies to contact the manufacturer for 
instructions on how to repair certain conditions, but this AD requires 
repairing those conditions 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 (ODA) whom we have 
authorized to make those findings.

FAA's Determination of the Effective Date

    An unsafe condition exists that requires the immediate adoption of 
this AD. The FAA has found that the risk to the flying public justifies 
waiving notice and comment prior to adoption of this rule because 
cracking in the lower skin at the lower row of fasteners of the lap 
joints at stringers S-4R and S-4L, along the entire length from BS 360 
to BS 908, could open up and result in an uncontrolled decompression of 
the airplane. Therefore, we find that notice and opportunity for prior 
public comment 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 was not preceded by notice and an opportunity for public 
comment. 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 the docket number FAA-2011-0348 and 
Directorate Identifier 2011-NM-069-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.

Costs of Compliance

    We estimate that this AD affects 195 airplanes of U.S. registry. We 
estimate the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                Cost on U.S.
        Action                Labor cost             Parts cost         Cost per product          operators
----------------------------------------------------------------------------------------------------------------
Inspections...........  6 or 15 work-hours     None.................  $510 or $1,275 per    $99,450 or $248,625
                         (depending on                                 inspection cycle.     per inspection
                         inspection method) x                                                cycle.
                         $85 per work-hour.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
a cost estimate for the on-condition actions (confirming crack 
indications and repairing cracks) specified in 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),
    (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

[[Page 28634]]

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):

2011-08-51 The Boeing Company: Amendment 39-16701; Docket No. FAA-
2011-0348; Directorate Identifier 2011-NM-069-AD.

Effective Date

    (a) This AD is effective June 2, 2011 to all persons except 
those persons to whom it was made immediately effective by Emergency 
AD 2011-08-51, issued on April 5, 2011, which contained the 
requirements of this amendment.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 737-300, -400, 
and -500 series airplanes, certificated in any category, as 
identified in Boeing Alert Service Bulletin 737-53A1319, dated April 
4, 2011.

Subject

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

Unsafe Condition

    (e) This AD was prompted by a report indicating that a Model 
737-300 series airplane experienced a rapid decompression when the 
lap joint at stringer S-4L between body station (BS) 664 and BS 727 
cracked and opened up due to cracking in the lower skin at the lower 
row of fasteners. We are issuing this AD to detect and correct such 
cracking, which could result in an uncontrolled decompression of the 
airplane.

Compliance

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

Inspections

    (g) At the applicable time specified in paragraph (g)(1), 
(g)(2), or (g)(3) of this AD: Except as provided by paragraphs (h) 
and (i) of this AD, do external eddy current inspections of the lap 
joint at stringers S-4R and S-4L, along the entire length from body 
station (BS) 360 to BS 908, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1319, dated 
April 4, 2011. If any crack indication is detected, before further 
flight, either confirm the crack indication by doing eddy current 
inspections from the interior of the fuselage in the lower skin at 
the lower row of fasteners at stringer S-4L and S-4R, in accordance 
with Boeing Alert Service Bulletin 737-53A1319, dated April 4, 2011, 
or repair in accordance with paragraph (j) of this AD.
    (1) For airplanes that have accumulated fewer than 30,000 total 
flight cycles as of the effective date of this AD: Inspect before 
the accumulation of 30,000 total flight cycles, or within 20 days 
after the effective date of this AD, whichever occurs later.
    (2) For airplanes that have accumulated 30,000 or more total 
flight cycles and fewer than 35,000 total flight cycles as of the 
effective date of this AD: Inspect within 20 days after the 
effective date of this AD.
    (3) For airplanes that have accumulated 35,000 total flight 
cycles or more as of the effective date of this AD: Inspect within 5 
days after the effective date of this AD.
    (h) For areas repaired with external doublers, paragraphs (h)(1) 
and (h)(2) of this AD apply.
    (1) If the repair meets the criteria specified in paragraphs 
3.B.1.c.(1) and 3.B.1.c.(2) of Boeing Alert Service Bulletin 737-
53A1319, dated April 4, 2011, no inspection of the lower skin at the 
lap joint lower fastener row is required under the doubler.
    (2) If the repair does not meet the criteria specified in 
paragraphs 3.B.1.c.(1) and 3.B.1.c.(2) of Boeing Alert Service 
Bulletin 737-53A1319, dated April 4, 2011, inspect the lower skin 
lap joint lower row internally in the area covered by the doubler, 
in accordance with Boeing Alert Service Bulletin 737-53A1319, dated 
April 4, 2011.
    (i) The inspections required by paragraph (g) of this AD may 
alternatively be done by internal eddy current and detailed 
inspections for cracks in the lower skin at the lower row of 
fasteners at stringer S-4L and S-4R, along the entire length from BS 
360 to BS 908, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1319, dated April 4, 2011.
    (j) If any crack is found during any inspection required by this 
AD: Before further flight, repair the crack using a method approved 
in accordance with the procedures specified in paragraph (l) of this 
AD.
    (k) Repeat the inspections specified in either paragraph (g) or 
(i) of this AD thereafter at intervals not to exceed 500 flight 
cycles. Either inspection method may be used at any repetitive 
inspection cycle.

Alternative Methods of Compliance (AMOCs)

    (l)(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 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.
    (4) AMOCs approved for emergency AD 2011-08-51 are approved as 
AMOCs for the corresponding requirements of this AD.

Related Information

    (m)(1) For further information about this AD, contact Wayne 
Lockett, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle 
Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; phone: 425-917-6447; fax: 425-917-6590; e-
mail: wayne.lockett@faa.gov.
    (2) For copies of the service information referenced in this AD, 
contact: Boeing Commercial Airplanes, Attention: Data & Services 
Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 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.

Material Incorporated by Reference

    (n) You must use Boeing Alert Service Bulletin 737-53A1319, 
dated April 4, 2011, 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, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 
206-544-5000, extension 1; fax 206-766-5680; e-mail 
me.boecom@boeing.com; Internet https://www.myboeingfleet.com.
    (3) You may review copies of the 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.
    (4) You may also review copies of the service information that 
is incorporated by reference at the National Archives and

[[Page 28635]]

Records Administration (NARA). For information on the availability 
of this material at an NARA facility, 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 6, 2011.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-11928 Filed 5-17-11; 8:45 am]
BILLING CODE 4910-13-P


