Airworthiness Directives; McDonnell Douglas Model MD-11 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes. This proposal would require electrical resistance measurements of the ground studs of the No. 2 generator in the electrical power center of the center accessory compartment for proper electrical bonding and of the ground studs and circuit breaker terminations in the forward cargo compartment to detect looseness and for proper electrical bonding; and corrective actions, if necessary. This proposal is prompted by an incident of charred insulation blankets in the forward cargo compartment in the area of the external ground power receptacle and the galley external power circuit breakers, and another incident of a No. 2 “generator off” alert while the generator was still on line. The actions specified by the proposed AD are intended to prevent arcing and overheating of terminals and consequent smoke and fire in the forward cargo compartment due to improper bonding of ground studs in the forward cargo compartment and in the electrical power center and due to improper installation of circuit breaker terminations.

DATES:

Comments must be received by March 17, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-269-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Dept. C1-L51 (2-60). This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT:

Brett Portwood, Aerospace Engineer, Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5350; fax (562) 627-5210.

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 notice may be changed in light of the comments received.

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 notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 99-NM-269-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. 99-NM-269-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Supplementary Information

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 one incident of charred insulation blankets in the forward cargo compartment in the area of the external ground power receptacle and the galley external power circuit breakers, and another incident of a No. 2 “generator off” alert while the generator was still on line. These incidents occurred on McDonnell Douglas Model MD-11 series airplanes. Investigation revealed that, during production, the ground studs in the forward cargo compartment and electrical power center (EPC) were bonded improperly. Also, investigation revealed that three of the nine circuit breaker terminations of the galley were loose due to improper installation during production. These conditions, if not corrected, could result in arcing and overheating of circuit breaker terminals and consequent smoke and fire in the forward cargo compartment.

This incident is not considered to be related to an accident that occurred off the coast of Nova Scotia involving a McDonnell Douglas Model MD-11 series airplane. The cause of that accident is still under investigation.

Other Related Rulemaking

The FAA, in conjunction with Boeing and operators of Model MD-11 series airplanes, is continuing to review 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 actions identified during that process. The process is continuing and the FAA may consider additional rulemaking actions as further results of the review become available.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas Alert Service Bulletin MD11-24A040, Revision 01, dated October 11, 1999, which describes procedures an electrical resistance measurement of the ground studs of the No. 2 generator in the electrical power center of the center accessory compartment for proper electrical bonding; and corrective actions, if necessary. The corrective actions include tightening the applicable fastener, if necessary, and electrically bonding the ground studs.

The service bulletin also describes procedures for an electrical resistance measurement of the ground studs and circuit breaker terminations in the forward cargo compartment to detect looseness and for proper electrical bonding, and corrective actions, if necessary. The corrective actions include tightening applicable attaching parts and electrically bonding the ground studs.

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, this proposed AD would require accomplishment of the actions specified in the service bulletin described previously.

Cost Impact

There are approximately 31 airplanes of the affected design in the worldwide fleet. The FAA estimates that 9 airplanes of U.S. registry would be affected by this proposed AD. It would take approximately 2 work hour per airplane to accomplish the proposed measurements, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the measurements proposed by this AD on U.S. operators is estimated to be $1,080, or $120 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 AD were not adopted.

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.