[Federal Register Volume 68, Number 233 (Thursday, December 4, 2003)]
[Proposed Rules]
[Pages 67812-67814]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-30192]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-327-AD]
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: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Model 737-600, 737-700, 
737-700C, 737-800, and 737-900 series airplanes. This proposal would 
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. 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: Comments must be received by January 20, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2002-NM-327-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2002-NM-327-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

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:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
    [sbull] Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
    [sbull] For each issue, state what specific change to the proposed 
AD is being requested.
    [sbull] Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NM-327-AD.'' The postcard will be date stamped 
and returned to the commenter.

[[Page 67813]]

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2002-NM-327-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report indicating that, during a routine 
inspection in production at Boeing, the electrical resistance of the 
ground studs installed on the support bracket for the fire extinguisher 
bottles in the left main wheel well of certain Boeing Model 737 series 
airplanes was found to exceed the maximum allowed level. 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. Therefore, the electrical resistance between the bracket and 
the grounding studs may exceed the maximum allowed resistance. This 
condition, if not corrected, 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.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-26A1118, dated October 17, 2002, which describes procedures for:
    [sbull] Measuring the electrical resistance of the dual ground 
studs to ensure that the electrical resistance is no greater than 0.5 
milliohms;
    [sbull] Measuring the bond resistance from the top terminal lug of 
each ground stud to the adjacent structure; and
    [sbull] Corrective actions, if necessary.
    The corrective actions include replacing the affected ground stud 
with a new ground stud; reworking the ground stud; and relocating the 
support bracket hole; as applicable. Accomplishment of the actions 
specified in the service bulletin is intended to adequately address the 
identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletin described previously, except as discussed below.

Difference Between Proposed Rule and Service Bulletin

    Because the service bulletin does not specify a corrective action 
to take if the bond resistance measurement found in Figure 4 of the 
service bulletin is greater than 1.0 milliohms, this proposed AD would 
require operators to rework per a method approved by the Manager, 
Seattle Aircraft Certification Office (ACO), FAA.

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 
would be affected by this proposed AD, that it would take approximately 
2 work hours per airplane to accomplish the proposed actions, and that 
the average labor rate is $65 per work hour. Based on these figures, 
the cost impact of the proposed 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 proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this proposed 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 proposed herein would 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 proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    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]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: 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, dated October 17, 2002; 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 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, dated October 17, 2002. 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 the Boeing Alert Service Bulletin 737-
26A1118, dated October 17, 2002, the resistance is found to be 
greater than 1.0 milliohms (0.001 ohms): Before further flight, 
rework per a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA.

Alternative Methods of Compliance

    (c) In accordance with 14 CFR 39.19, the Manager, Seattle 
Aircraft Certification Office,

[[Page 67814]]

FAA, is authorized to approve alternative methods of compliance 
(AMOCs) for this AD.

    Issued in Renton, Washington, on November 28, 2003.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-30192 Filed 12-3-03; 8:45 am]
BILLING CODE 4910-13-P