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:

• 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.

For each issue, state what specific change to the proposed AD is being requested. ( printed page 61773)

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 2000-NM-168-AD.” The postcard will be date stamped and returned to the commenter.

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. 2000-NM-168-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

As part of its practice of re-examining all aspects of the service experience of a particular aircraft whenever an accident occurs, the FAA has become aware of several incidents of migration of power feeder cable troughs on McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes. The migration occurred where cables pass through lightening holes into forward and aft lower cargo compartments. Investigation revealed that the cause of such migration is vibration. Migration of the trough could result in a cable chafing against an edge of a lightening hole, which could result in electrical arcing, and consequent smoke/fire in the lower cargo compartments.

Other Related Rulemaking

The FAA, in conjunction with Boeing and operators of McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes, has reviewed all aspects of the service history of those airplanes to identify potential unsafe conditions and to take appropriate corrective actions. This proposed airworthiness directive (AD) is one of a series of corrective actions identified during that process. We have previously issued several other ADs and may consider further rulemaking actions to address the remaining identified unsafe conditions.

On April 14, 1994, the FAA issued AD 94-09-02, amendment 39-8890 (59 FR 18720, April 20, 1994). That AD requires inspecting the auxiliary power unit (APU) for power feeder cable damage, and repair of the cable if necessary; then modifying the cable installation. Those actions are required to eliminate a potential source of fire ignition from electrical shorting of the generator power feeder cable. That AD also requires inspecting previously modified airplanes to determine whether a spacer or “stand off” had been installed, and installing those items if necessary. Those actions are required to prevent the power feeder cable for the APU from chafing against adjacent structures, which could result in electrical shorting and arcing, and a fire below the cabin floor.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas Alert Service Bulletin MD80-24A100, Revision 04, dated January 24, 2000, which describes procedures for installing shield assemblies for power feeder cables in the forward and aft lower cargo compartments, and installing an additional shield for the power feeder cable of the auxiliary power unit in the aft lower cargo compartment.

Accomplishment of the actions specified in the service bulletin will protect the power feeder cables from contact with the edge of a lightening hole when trough migration occurs, and 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.

Cost Impact

There are approximately 473 airplanes of the affected design in the worldwide fleet. The FAA estimates that 275 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed installation, and that the average labor rate is $65 per work hour. Required parts would cost approximately between $674 and $3,656 per airplane. Based on these figures, the cost impact of the proposed installation on U.S. operators of these airplanes is estimated to be between $203,225 and $1,023,275, or between $739 and $3,721 per airplane.

The cost impact figures discussed above are 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. The manufacturer may cover the cost of parts associated with this proposed AD, subject to warranty conditions. Manufacturer warranty remedies also may be available for labor costs associated with this proposed AD. As a result, the costs attributable to the proposed AD may be less than stated above.

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 ( printed page 61774) 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.

§ 39.13

[Amended]

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

McDonnell Douglas: Docket 2000-NM-168-AD.

Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 airplanes, as listed in McDonnell Douglas Alert Service Bulletin MD80-24A100, Revision 04, dated January 24, 2000; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent a cable from chafing against an edge of a lightening hole, which could result in electrical arcing, and consequent smoke/fire in the lower cargo compartments, accomplish the following:

Installation

(a) Within 1 year after the effective date of this AD, install shield assemblies for power feeder cables in the forward and aft lower cargo compartments, and install an additional shield for the power feeder cable of the auxiliary power unit in the aft lower cargo compartment, per the Accomplishment Instructions of McDonnell Douglas Alert Service Bulletin MD80-24A100, Revision 04, dated January 24, 2000.

Installations Accomplished per Previous Issues of Service Bulletin

(b) Installations accomplished before the effective date of this AD per McDonnell Douglas Service Bulletin MD80-24-100, original issue, dated March 30, 1988, through Revision 3, dated March 15, 1991, are considered acceptable for compliance with the actions specified in paragraph (a) of this AD.

Alternative Methods of Compliance

(c) In accordance with 14 CFR 39.19, the Manager, Los Angeles Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD.

Issued in Renton, Washington, on October 24, 2003.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.