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-212-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-212-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 incidents of smoke and electrical odor in the flight compartment and cabin area of McDonnell Douglas Model DC-9 series airplanes. Investigation revealed that long-term use and break down of the internal components of the circuit breakers, manufactured by Wood Electric Corporation or Wood Electric Division of Potter Brumfield Corporation, contributed to internal overheating and arcing of the circuit breakers. This condition, if not corrected, could result in smoke and fire in the flight compartment and main cabin.

The subject circuit breakers on certain Model DC-10 series airplanes are similar to those on the affected McDonnell Douglas Model DC-9 series airplanes. Therefore, both of these models may be subject to this same unsafe condition.

Other Related Rulemaking

The FAA is considering further rulemaking for certain McDonnell Douglas Model DC-9 series airplanes to address the identified unsafe condition.

The FAA, in conjunction with Boeing and operators of Model DC-10 series ( printed page 4189) 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 DC10-24A161, dated October 29, 1999. The service bulletin describes procedures for a one-time general visual inspection of circuit breakers to determine the manufacturer of the circuit breakers, and replacement of any circuit breaker manufactured by Wood Electric Corporation or Wood Electric Division of Potter Brumfield Corporation with a new circuit breaker. 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, except as discussed below.

Differences Between Proposed AD and Service Bulletin

Operators should note that the proposed AD would require replacement of any circuit breaker manufactured by Wood Electric Corporation or Wood Electric Division of Potter Brumfield Corporation with a new circuit breaker within 18 months after the effective date of this AD. The service bulletin recommends that the replacement should be accomplished within 12 months from the issuance of the service bulletin. In developing an appropriate compliance time for this proposed action, the FAA considered not only the degree of urgency associated with addressing the subject unsafe condition, but the availability of required parts. The FAA has determined that 18 months represents an appropriate interval of time allowable wherein an ample number of required parts will be available for modification of the U.S. fleet within the proposed compliance period. The FAA also finds that such a compliance time will not adversely affect the safety of the affected airplanes.

Cost Impact

There are approximately 412 airplanes of the affected design in the worldwide fleet. The FAA estimates that 300 airplanes of U.S. registry would be affected by this proposed AD, it would take approximately 80 work hours per airplane to accomplish the proposed inspection of the circuit breakers (over 700 installed on each airplane), and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $1,440,000, or $4,800 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 .

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: