Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes, 21254-21255 [E9-9947]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 74, Number 87 (Thursday, May 7, 2009)]
[Rules and Regulations]
[Pages 21254-21255]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-9947]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1275; Directorate Identifier 2007-NM-167-AD; 
Amendment 39-15892; AD 2009-09-06]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Boeing Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. This AD requires repetitive detailed and high frequency eddy 
current inspections to detect cracks of the backup intercostals and the 
upper sill of the forward airstair doorway, and applicable corrective 
actions. This AD also provides for an optional terminating action, 
which would eliminate the need for repetitive inspections. This AD 
results from a report indicating that cracks were found in the backup 
intercostals and upper sill web of the forward airstair doorway. We are 
issuing this AD to detect and correct fatigue cracking of the backup 
intercostals and upper sill web of the forward airstair doorway, which 
could result in a rapid loss of cabin pressure.

DATES: This AD is effective June 11, 2009.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of June 11, 
2009.

ADDRESSES: 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&fnl; https://www.myboeingfleet.com.

Examining the AD Docket

    You may examine the AD docket on the Internet at https://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 (telephone 800-647-5527) is the 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: Alan Pohl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6450; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an airworthiness directive (AD) that would apply to 
certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. That NPRM was published in the Federal Register on December 
5, 2008 (73 FR 74080). That NPRM proposed to require repetitive 
detailed and high frequency eddy current inspections to detect cracks 
of the backup intercostals and the upper sill of the forward airstair 
doorway, and applicable corrective actions. That NPRM also provided an 
optional terminating action, which would eliminate the need for 
repetitive inspections.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comments received from the two commenters.

Support for the NPRM

    Boeing concurs with the contents of the NPRM.

Request for Clarification

    Southwest Airlines requests more information regarding alternative 
procedures for airplanes that have had the airstair door deactivated 
per Boeing Service Bulletin 737-52-1092. Southwest Airlines asks 
whether instructions developed by operators, for open and close of an 
airstair door after deactivation per Boeing Service Bulletin 737-52-
1092, will be considered approved equivalent procedures.
    No alternative procedures have been established that have general 
FAA approval; however, according to the provisions of paragraph (h) of 
the final rule we may approve requests for different compliance methods 
if the requests include data that prove that the new methods would 
provide an acceptable level of safety.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD as proposed.

Costs of Compliance

    There are 1,712 airplanes of the affected design in the worldwide 
fleet. This AD affects 509 airplanes of U.S. registry. The inspections 
take 2 work hours per airplane, at an average labor rate of $80 per 
work hour. Based on these figures, the estimated cost of the AD for 
U.S. operators is $81,440, or $160 per airplane, per inspection cycle.
    The optional terminating action, if done, would take 9 work hours, 
at an average labor rate of $80 per work hour. Required parts cost 
between $533 and $566 per airplane, depending on the airplane 
configuration. Based on these figures, the estimated cost of the 
optional terminating action would range between $1,253 and $1,286 per 
airplane, depending on the airplane configuration.

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

[[Page 21255]]

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), 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
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 AD:

2009-09-06 Boeing: Amendment 39-15892. Docket No. FAA-2008-1275; 
Directorate Identifier 2007-NM-167-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective June 11, 
2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-100, -200, -200C, -300, 
-400, and -500 series airplanes, certificated in any category; as 
identified in Boeing Alert Service Bulletin 737-53A1269, dated May 
17, 2007.

Unsafe Condition

    (d) This AD results from a report indicating that cracks were 
found in the backup intercostals and upper sill web of the forward 
airstair doorway. We are issuing this AD to detect and correct 
fatigue cracking of the backup intercostals and upper sill web of 
the forward airstair doorway, which could result in a rapid loss of 
cabin pressure.

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.

Inspections

    (f) At the applicable compliance times and repeat intervals 
listed in the tables of paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin 737-53A1269, dated May 17, 2007 (hereafter 
``the service bulletin''), except as provided by paragraphs (f)(1), 
(f)(2), and (f)(3) of this AD: Do repetitive detailed and high 
frequency eddy current inspections to detect cracks of the backup 
intercostals and the upper sill of the forward airstair doorway, and 
applicable corrective actions by accomplishing all the applicable 
actions specified in the Accomplishment Instructions of the service 
bulletin. Do the applicable corrective actions before further 
flight.
    (1) Where the service bulletin specifies a compliance time from 
the release date of the service bulletin, this AD requires 
compliance within the specified compliance time after the effective 
date of this AD.
    (2) Where the columns identified as ``Airplane Flight Cycles'' 
in the tables of the service bulletin specify less than 45,000 total 
flight cycles for certain actions, this AD affects airplanes having 
less than or equal to 45,000 total flight cycles.
    (3) Where the columns identified as ``Repeat Interval'' in the 
tables of the service bulletin specify an interval of 4,500 flight 
cycles for all conditions, this AD requires repetitive inspections 
only if no crack is found during any inspection required by 
paragraph (f) of this AD.

Optional Terminating Action

    (g) Accomplishing the backup intercostal repair/preventative 
modification and/or the upper door sill web repair, in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1269, dated May 17, 2007, terminates all the 
corresponding repetitive inspection requirements of paragraph (f) 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 
using the procedures found in 14 CFR 39.19. Send information to 
ATTN: Alan Pohl, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, 
Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; 
telephone (917) 917-6450; fax (425) 917-6590.
    (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 principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, or lacking a 
principal inspector, your local Flight Standards District Office. 
The AMOC approval letter must specifically reference this AD.
    (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, FAA, 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.

Material Incorporated by Reference

    (i) You must use Boeing Alert Service Bulletin 737-53A1269, 
dated May 17, 2007, to do the actions required by this AD, unless 
the AD specifies otherwise. The optional actions specified by this 
AD, if accomplished, must also be done in accordance with Boeing 
Alert Service Bulletin 737-53A1269, dated May 17, 2007.
    (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 or 425-227-1152.
    (4) 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: https://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on April 22, 2009.
Stephen P. Boyd,
Assistant Manager, Transport Airplane Directorate, Aircraft 
Certification Service.
[FR Doc. E9-9947 Filed 5-6-09; 8:45 am]
BILLING CODE 4910-13-P