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

[Federal Register Volume 70, Number 48 (Monday, March 14, 2005)]
[Rules and Regulations]
[Pages 12410-12411]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-4829]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19022; Directorate Identifier 2004-NM-122-AD; 
Amendment 39-14007; AD 2005-05-18]
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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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Boeing Model 737-600, -700, -700C, -800, and -900 series 
airplanes. This AD requires repetitive detailed, low frequency eddy 
current, and high frequency eddy current inspections of the webs of the 
aft pressure bulkhead at body station 1016 for cracks, and corrective 
action if necessary. This AD is prompted by a report of cracks found, 
during fatigue testing, at several of the fastener rows in the web lap 
splices at the dome apex of the aft pressure bulkhead. We are issuing 
this AD to detect and correct fatigue cracks in the webs of the aft 
pressure bulkhead, which could result in rapid decompression of the 
airplane.

DATES: This AD becomes effective April 18, 2005.
    The incorporation by reference of a certain publication listed in 
the AD is approved by the Director of the Federal Register as of April 
18, 2005.

ADDRESSES: For service information identified in this AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207.
    Docket: The AD docket contains the proposed AD, comments, and any 
final disposition. You can examine the 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 U.S. 
Department of Transportation, 400 Seventh Street, SW., room PL-401, 
Washington, DC. This docket number is FAA-2004-19022; the directorate 
identifier for this docket is 2004-NM-122-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: The FAA proposed to amend 14 CFR Part 39 
with an AD for certain Boeing Model 737-600, -700, -700C, -800, and -
900 series airplanes. That action, published in the Federal Register on 
September 7, 2004 (69 FR 54053), proposed to require repetitive 
detailed, low frequency eddy current, and high frequency eddy current 
inspections of the webs of the aft pressure bulkhead at body station 
1016 for cracks, and corrective action if necessary.

Actions Since Notice of Proposed Rulemaking (NPRM) Was Issued

    Since the NPRM was issued, Boeing has received a Delegation Option 
Authorization (DOA). We have revised this final rule to delegate the 
authority to approve an alternative method of compliance (AMOC) for any 
repair required by this AD to an Authorized Representative for the 
Boeing DOA Organization rather than a Designated Engineering 
Representative.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comment that has been 
submitted on the proposed AD.

Request for Repair or Preventative Modification

    The commenter, an operator, requests that the manufacturer add 
either repair instructions or a preventative modification and task hour 
estimate for the respective action to Boeing Service Bulletin 737-53-
1251, dated June 3, 2004. The commenter states that the service 
bulletin does not recommend any repair or terminating action if cracks 
are found during inspection of the aft pressure bulkhead, but instead 
specifies contacting the manufacturer if cracks are found.
    Although we agree with the intent of the commenter's request, we 
also know that variations in the type and degree of damage at and 
around the web lap splices at the dome apex of the aft pressure 
bulkhead make it difficult to develop general repair instructions, or a 
preventative modification, that could be applicable to and effective 
for all conditions. Furthermore, the manufacturer has experience 
repairing damage in the area of the web lap splices of the aft pressure 
bulkhead and can assist in developing repairs appropriate for specific 
conditions. For these reasons, we are allowing the Manager, Seattle 
Aircraft Certification Office, FAA, or an Authorized Representative for 
the Boeing DOA Organization to approve repairs in accordance with 
paragraph (g) of this final rule. If general repair instructions or a 
preventative modification should be developed at a later time, and the 
service bulletin is revised to include either of these actions, we will 
consider approving the revised service bulletin as an AMOC to this 
final rule. Therefore, no change is necessary to this final rule in 
this regard.

Explanation of Editorial Change

    For clarification, we have replaced the word ``listed'' with 
``identified'' to specify the applicability in paragraph (c) of this 
AD.

Conclusion

    We have carefully reviewed the available data, including the 
comment that has been submitted, and determined that air safety and the 
public interest require adopting the AD with the changes described 
previously. We have determined that these changes will neither increase 
the economic

[[Page 12411]]

burden on any operator nor increase the scope of the AD.

Costs of Compliance

    This AD affects about 457 airplanes of U.S. registry and 1,166 
airplanes worldwide. The actions will take about 8 work hours per 
airplane, at an average labor rate of $65 per work hour. Based on these 
figures, the estimated cost of the AD for U.S. operators is $237,640, 
or $520 per airplane, per inspection cycle.

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

2005-05-18 Boeing: Amendment 39-14007. Docket No. FAA-2004-19022; 
Directorate Identifier 2004-NM-122-AD.

Effective Date

    (a) This AD becomes effective April 18, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-600, -700, -700C, -800, 
and -900 series airplanes, certificated in any category; as 
identified in Boeing Service Bulletin 737-53-1251, dated June 3, 
2004.

Unsafe Condition

    (d) This AD was prompted by a report of cracks found, during 
fatigue testing, at several of the fastener rows in the web lap 
splices at the dome apex of the aft pressure bulkhead. We are 
issuing this AD to detect and correct fatigue cracks in the webs of 
the aft pressure bulkhead, which could result in rapid decompression 
of the airplane.

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.

Initial and Repetitive Inspections

    (f) Prior to accumulating 26,000 total flight cycles or within 
4,000 flight cycles after the effective date of this AD, whichever 
occurs later: Do a detailed inspection, low frequency eddy current 
inspection, and high frequency eddy current inspection of the webs 
of the aft pressure bulkhead at body station 1016 for cracks, in 
accordance with Boeing Service Bulletin 737-53-1251, dated June 3, 
2004. Repeat the inspections thereafter at intervals not to exceed 
4,000 flight cycles.

    Note 1: For the purposes of this AD, a detailed inspection is: 
``An intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirror, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

Corrective Action

    (g) If any crack is found during any inspection required by 
paragraph (f) of this AD: Before further flight, repair according to 
a method approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA; or according to data meeting the certification 
basis of the airplane approved by an Authorized Representative for 
the Boeing Delegation Option Authorization (DOA) Organization who 
has been authorized by the Manager, Seattle ACO, to make those 
findings. For a repair method to be approved, the approval must 
specifically reference this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(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 any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing DOA 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.

Material Incorporated by Reference

    (i) You must use Boeing Service Bulletin 737-53-1251, dated June 
3, 2004, to perform the actions that are required by this AD, unless 
the AD specifies otherwise. The Director of the Federal Register 
approves the incorporation by reference of this document in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. For copies of the 
service information, contact Boeing Commercial Airplanes, P.O. Box 
3707, Seattle, Washington 98124-2207. For information on the 
availability of this material at the National Archives and Records 
Administration (NARA), call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. You may view the AD docket at the Docket 
Management Facility, U.S. Department of Transportation, 400 Seventh 
Street SW., room PL-401, Nassif Building, Washington, DC.

    Issued in Renton, Washington, on March 2, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-4829 Filed 3-11-05; 8:45 am]
BILLING CODE 4910-13-P

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