[Federal Register Volume 70, Number 203 (Friday, October 21, 2005)]
[Rules and Regulations]
[Pages 61226-61229]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-20966]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-21086; Directorate Identifier 2004-NM-217-AD; 
Amendment 39-14344; AD 2005-21-06]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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[[Page 61227]]

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. 
This AD requires repetitive inspections of the aft pressure bulkhead 
web for fatigue cracks, crack indications, discrepant holes, and 
corrosion; and repair if necessary. This AD results from reports of 
fatigue cracks in the aft pressure bulkhead web. We are issuing this AD 
to detect and correct such fatigue cracks, which could result in a 
rapid decompression of the airplane.

DATES: This AD becomes effective November 25, 2005.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of November 25, 
2005.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., Nassif Building, 
room PL-401, Washington, DC.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Howard Hall, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6430; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is located on the plaza level of the Nassif 
Building at the street address stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to all Boeing Model 737-
600, -700, -700C, -800, and -900 series airplanes. That NPRM was 
published in the Federal Register on May 2, 2005 (70 FR 22620). That 
NPRM proposed to require repetitive inspections of the aft pressure 
bulkhead web for fatigue cracks, crack indications, discrepant holes, 
and corrosion; and repair if necessary.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Supportive Comments

    Two commenters, including the manufacturer, support the proposed 
AD.

Request To Add Provision for Special Flight Permits

    One commenter requests that the proposed AD be revised to include a 
phrase used in earlier ADs to permit the use of special flight permits. 
The commenter explains that, due to the number of work hours needed to 
gain access to the forward side of the aft pressure bulkhead, it needs 
to use the provisions for special flight permits. We infer that the 
commenter believes that because the proposed AD does not contain 
information on ferry flights, ferry flights are not allowed.
    We do not agree with the commenter's request to add the special 
flight permit language, nor do we agree with the commenter's inference 
that special flight permits are not allowed by this AD. Special flight 
permits are allowed unless limitations or prohibitions are specifically 
identified in the AD. For this AD there are no limitations or 
prohibitions. On July 10, 2002, we issued a new version of 14 CFR part 
39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. The regulation now includes material that relates to 
altered products, special flight permits (i.e., ferry flights), and 
alternative methods of compliance (AMOCs). Since we have now included 
this information in 14 CFR part 39, information on special flight 
permits is not included in each individual AD unless there are 
limitations on special flight permits for an individual AD. We have not 
changed the AD in this regard.

Request To Add Language That Advises Operators How To Address Pre-
existing Repairs

    Another commenter requests that the proposed AD be revised to 
include language advising operators how to treat pre-existing repairs 
in the inspection area of the aft pressure bulkhead. The commenter 
justifies the request by noting that the ``* * * bulkhead is the 
subject of numerous other service bulletins and other ADs, any or all 
of which may have resulted in the installation of repairs in the 
inspection area,'' and that the absence of such advisory language would 
require AMOCs for each instance of pre-existing repairs. We infer that 
the commenter believes that the AD requires AMOCs for each pre-existing 
repair that prevents someone from complying with the requirements of 
the AD, and is requesting that the AD include specific language to 
provide relief for treating these pre-existing repairs.
    We understand the commenter's concern about obtaining AMOCs for 
pre-existing repairs, especially since there are three ADs that cover 
the inspection area. We concur with the commenter in this regard. As 
noted in the reply to the previous comment on special flight permits, 
we issued a new version of 14 CFR part 39 on July 10, 2002. In section 
39.17, it states, ``If a change in a product affects your ability to 
accomplish the actions required by the airworthiness directive in any 
way, you must request FAA approval of an alternative method of 
compliance.'' This statement means that pre-existing repairs do not 
require AMOC approval unless they affect the operator's ability to 
accomplish the actions of the AD. Since we cannot anticipate the wide 
variety of possible repair configurations, this is best handled by 
requesting an AMOC for each repair. We have not changed the AD in this 
regard.

Request To Query Boeing for Availability of Parts

    One commenter notes that certain repairs would require replacement 
of sections of curved structural members that are difficult for 
operators to fabricate on short notice. The commenter suggests that 
Boeing should be queried for availability of replacement materials in 
the event that an inspection finds the need for corrective action.
    We agree that certain parts may be difficult for operators to 
fabricate on short notice (i.e., before further flight). We contacted 
Boeing about parts availability in regard to this AD, and have 
confirmed that a sufficient quantity of parts is available. We 
encourage operators to contact Boeing for specific information on parts 
availability. We have not changed the AD in this regard.

Request to Operator for Additional Repair Guidance

    One commenter requests that Boeing provide additional repair 
guidance other than ``contact Boeing.'' The commenter notes that the 
manufacturer has previous experience in addressing similar repairs in 
the area to be inspected in accordance with this AD. The commenter 
acknowledges that every repair is different, but believes that a repair 
drawing or structural-repair-manual-type of repair should be

[[Page 61228]]

made available. The commenter also states that it is impractical to 
contact Boeing in an airline's operational environment.
    We acknowledge the commenter's request. We understand that general 
repair information applicable to this AD would help operators plan for 
any potential corrective action. We have coordinated this issue with 
Boeing. However, in this particular area, it is difficult to develop 
specific guidelines for the various conditions that an operator may 
encounter. Although no general repair information exists now (at time 
of publication), we remind operators that we may approve (if submitted 
and approved) repair drawings as allowed for in paragraph (i) of this 
AD, which describes ways to get approval of an alternative method of 
compliance (AMOC). We remind operators that they may apply for an AMOC 
in accordance with the provisions in paragraphs (i) and (g) of this AD. 
We have not changed the AD in this regard.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD as proposed.

Explanation of Change Made to This AD

    We have simplified paragraph (g) of this AD by referring to the 
``Alternative Methods of Compliance (AMOCs)'' paragraph of this AD for 
repair methods.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

    We have revised this AD to clarify the appropriate procedure for 
notifying the principal inspector before using any approved AMOC on any 
airplane to which the AMOC applies.

Costs of Compliance

    There are about 978 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this AD:

                                                                     Estimated Costs
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                                                                                                    Number of
                                 Work     Average                                                     U.S.-
            Action              hours    labor rate    Parts            Cost per airplane           registered                 Fleet cost
                                          per hour                                                  airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
LFEC and detailed inspection,        8          $65  None.....  $520 per inspection cycle........          630  $327,600 per inspection cycle.
 per inspection cycle.
HFEC and detailed inspection         2           65  None.....  $130 per inspection cycle........          630  $81,900 per inspection cycle.
 (in lieu of LFEC and
 detailed inspection), per
 inspection cycle.
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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 have determined that 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); 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

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

2005-21-06 Boeing: Amendment 39-14344. Docket No. FAA-2005-21086; 
Directorate Identifier 2004-NM-217-AD.

Effective Date

    (a) This AD becomes effective November 25, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 737-600, -700, -700C, -
800, and -900 series airplanes, certificated in any category.

Unsafe Condition

    (d) This AD was prompted by reports of fatigue cracks in the aft 
pressure bulkhead web. We are issuing this AD to detect and correct 
such fatigue cracks, which could result in rapid decompression of 
the airplane.

[[Page 61229]]

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 ``Inspection Threshold'' in the table in 
Part 1.E. ``Compliance'' of Boeing Alert Service Bulletin 737-
53A1248, dated September 9, 2004, or within 18 months after the 
effective date of this AD, whichever occurs later, and thereafter at 
intervals not to exceed the applicable ``Inspection Repeat 
Interval'' in that table: Do the inspections (i.e., detailed 
inspection and either high- or low-frequency eddy current 
inspections) of the aft pressure bulkhead web for fatigue cracks, 
crack indications, discrepant holes, and corrosion, in accordance 
with the Accomplishment Instructions of the service bulletin.

Corrective Action Difference

    (g) If any fatigue crack, crack indication, discrepant hole, or 
corrosion is found during any inspection required by this AD, before 
further flight, repair the fatigue crack, crack indication, 
discrepant hole, and corrosion according to a method approved by the 
Manager, Seattle Aircraft Certification Office (ACO), FAA; or using 
a method approved in accordance with the procedures specified in 
paragraph (i) of this AD.

No Reporting

    (h) Although the service bulletin references a reporting 
requirement in the Accomplishment Instructions, that reporting is 
not required by this AD.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Seattle ACO, FAA, has the authority to 
approve AMOCs for this AD, if requested in accordance with the 
procedures found in 14 CFR 39.19.
    (2) An AMOC that provides an acceptable level of safety may be 
used for corrective actions, 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, 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.
    (3) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Material Incorporated by Reference

    (j) You must use Boeing Alert Service Bulletin 737-53A1248, 
dated September 9, 2004, to perform the actions that are required by 
this AD, unless the AD specifies otherwise. The Director of the 
Federal Register approved the incorporation by reference of this 
document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for a copy of this service information. You 
may review copies at the Docket Management Facility, U.S. Department 
of Transportation, 400 Seventh Street, SW., room PL-401, Nassif 
Building, Washington, DC; on the Internet at http://dms.dot.gov; or 
at the National Archives and Records Administration (NARA). For 
information on the availability of this material at the NARA, 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 October 13, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-20966 Filed 10-20-05; 8:45 am]
BILLING CODE 4910-13-P