[Federal Register Volume 69, Number 170 (Thursday, September 2, 2004)]
[Rules and Regulations]
[Pages 53605-53607]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-19855]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-327-AD; Amendment 39-13779; AD 2004-18-02]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 737-600, 737-700, 737-700C, 737-800, 
and 737-900 series airplanes, that requires measuring the electrical 
resistance of the support bracket for the fire extinguisher bottle 
located in the left main landing gear wheel well to ensure that it does 
not exceed the maximum allowed resistance; and corrective actions, if 
necessary. This action is necessary to prevent high electrical 
resistance in the squib firing circuit, which could result in 
insufficient electrical current to fire the fire extinguisher bottle 
squib and discharge the fire extinguishing agent, which could lead to 
an uncontrolled engine fire. This action is intended to address the 
identified unsafe condition.

DATES: Effective October 7, 2004.
    The incorporation by reference of a certain publication listed in 
the regulations is approved by the Director of the Federal Register as 
of October 7, 2004.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington; or 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: 
http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

FOR FURTHER INFORMATION CONTACT: Doug Pegors, Aerospace Engineer; 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (425) 917-
6504; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 737-600, 737-
700, 737-700C, 737-800, and 737-900 series airplanes was published in 
the Federal Register on December 4, 2003 (68 FR 67812). That action 
proposed to require measuring the electrical resistance of the support 
bracket for the fire extinguisher bottle located in the left main 
landing gear wheel well to ensure that it does not exceed the maximum 
allowed resistance; and corrective actions, if necessary.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for the Proposal

    Two commenters, who do not have airplanes affected by the proposed 
AD, either do not object to or agree with the proposed AD.

[[Page 53606]]

Request To Give Credit for Boeing Telex

    One commenter, an airplane operator, noted that the actions 
proposed in the notice of proposed rulemaking (NPRM) are based on 
Boeing Telex M-7200-02-01401, dated September 9, 2002. The operator 
states that immediate action based on the telex was necessary due to 
safety concerns, and it did not wait for Boeing to issue the related 
service bulletin before taking the necessary actions. The commenter 
proposes that the telex should be included in the final rule as an 
acceptable means for compliance with the proposed actions.
    We agree with the commenter. We have included Boeing Telex M-7200-
02-01401, dated September 9, 2002, in a new paragraph (c) of the final 
rule to allow credit for accomplishment of the required actions per 
that telex.

Request To Include New Revision of Service Bulletin

    Another commenter, the airplane manufacturer, requests that Boeing 
Alert Service Bulletin 737-26A1118, Revision 1, dated April 8, 2004, be 
included as the appropriate source of service information for the final 
rule. The commenter states that a typographical error in the original 
release of the service bulletin (dated October 17, 2002) makes it 
impossible for any correctly configured airplane to pass the continuity 
test in the work instructions. In addition, as noted in the NPRM, the 
original release of the service bulletin did not have explicit 
instructions for reworking the terminal installation if the resistance 
requirement is not met. The commenter states that, if Revision 1 of the 
service bulletin is included in the final rule, paragraph (b) 
(``Additional Rework'') should be deleted, and paragraph (a) should be 
revised to exclude a reference to paragraph (b).
    We partially agree with the commenter's request. In a further 
engineering review, we determined that there is no typographical error 
in the original release of the service bulletin that makes it 
impossible for airplanes to pass the continuity test. However, we have 
revised the applicability section and paragraphs (a) and (b) of the 
final rule to include Revision 1 of the service bulletin, which is the 
most current source of service information for the actions in this AD. 
We have not deleted paragraph (b), but instead have revised it to allow 
operators to rework the terminal installation in accordance with either 
Revision 1 of the service bulletin, or in accordance with a method 
approved by the FAA, as proposed in the NPRM. The new paragraph (c) of 
this final rule also allows credit for actions done in accordance with 
the original issue of the service bulletin.

Request To Revise Wording Regarding Anodize Coating

    The same commenter requests that the following sentence in the 
``Discussion'' section of the NPRM be revised: ``During manufacture, 
the anodize coating was not removed properly from the holes in the 
support bracket into which the ground studs are inserted, thereby 
increasing the electrical resistance between the studs and the 
bracket.'' The commenter notes that the anodize coating surrounding the 
hole was also improperly prepared for an electrical bond.
    We partially agree with the commenter's request, which provides a 
more accurate description of the unsafe condition. However, the 
``Discussion'' paragraph is included in an NPRM as a description of the 
unsafe condition to provide adequate information to the public during 
the comment period. The ``Discussion'' paragraph is not included in the 
final rule. Therefore, we have not changed the information in the final 
rule, but have provided the commenter's information above for the sake 
of accuracy.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 133 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 28 airplanes of U.S. registry 
will be affected by this AD, that it will take approximately 2 work 
hours per airplane to accomplish the required actions, and that the 
average labor rate is $65 per work hour. Based on these figures, the 
cost impact of the AD on U.S. operators is estimated to be $3,640, or 
$130 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted. The cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

Regulatory Impact

    The regulations adopted herein 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness 
directive:

2004-18-02 Boeing: Amendment 39-13779. Docket 2002-NM-327-AD.

    Applicability: Model 737-600, 737-700, 737-700C, 737-800, and 
737-900 series airplanes, as listed in Boeing Alert Service Bulletin 
737-26A1118, Revision 1, dated April 8, 2004; certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent high electrical resistance in the squib firing 
circuit, which could result in

[[Page 53607]]

insufficient electrical current to fire the fire extinguisher bottle 
squib and discharge the fire extinguishing agent, which could lead 
to an uncontrolled engine fire, accomplish the following:

Inspection, Rework, Replacement, Relocation, and Installation

    (a) Except as provided by paragraph (b) of this AD: Within 90 
days after the effective date of this AD, measure the electrical 
resistance of the dual ground studs of the support brackets for the 
fire extinguisher bottle located in the left main landing gear wheel 
well (including the applicable corrective actions) by accomplishing 
all actions specified in the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-26A1118, Revision 1, dated April 8, 2004. 
Do the actions per the service bulletin. Any applicable corrective 
action must be accomplished prior to further flight.

Additional Rework

    (b) If, when accomplishing the bond resistance measurement 
described in Figure 4 of Boeing Alert Service Bulletin 737-26A1118, 
Revision 1, dated April 8, 2004, the resistance is found to be 
greater than 1.0 milliohms (0.001 ohms): Before further flight, do 
the actions in paragraph (b)(1) or (b)(2) of this AD.
    (1) Rework the terminal installation per Figure 4 of the service 
bulletin.
    (2) Rework the terminal installation per a method approved by 
the Manager, Seattle Aircraft Certification Office, FAA.

Actions Accomplished per Boeing Telex and Previous Issue of Service 
Bulletin

    (c) Actions accomplished before the effective date of this AD 
per Boeing Telex M-7200-02-01401, dated September 9, 2002; or Boeing 
Alert Service Bulletin 737-26A1118, dated October 17, 2002; are 
considered acceptable for compliance with the corresponding action 
specified in this AD.

Alternative Methods of Compliance

    (d) In accordance with 14 CFR 39.19, the Manager, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056, is authorized to approve alternative methods 
of compliance (AMOCs) for this AD.

Incorporation by Reference

    (e) Unless otherwise specified in this AD, the actions shall be 
done in accordance with Boeing Alert Service Bulletin 737-26A1118, 
Revision 1, dated April 8, 2004. This incorporation by reference was 
approved by the Director of the Federal Register in accordance with 
5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 
98124-2207. Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or 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: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

Effective Date

    (f) This amendment becomes effective on October 7, 2004.

    Issued in Renton, Washington, on August 20, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-19855 Filed 9-1-04; 8:45 am]
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