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 FAApublic 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 selfaddressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 2000NM268AD.'' 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, ANM114, Attention: Rules Docket No. 2000NM268AD, 1601 Lind Avenue, SW., Renton, Washington 980554056.

Discussion

The FAA has received reports indicating two incidents, on a Boeing Model 767300 series airplane, of wire bundle chafing and subsequent arcing against a ceiling support bracket attached to the F4/G2 galley at body station 355. In the first incident, approximately 20 wire segments were burnt and severed, which resulted in smoke in the cabin, release of oxygen masks, tripping of various circuit breakers, loss of flightessential systems, and an air turnback. In the second incident, there was a flash and static noise followed by a shower of sparks and ash. During an inspection on a recently delivered Model 767300 series airplane, a potential chafing condition was found between the same wire bundles and support bracket described above.

Because these wires are connected to such flightessential systems as the fuel shutoff valves for the engines, oxygen deployment for passengers, emergency lighting, passenger signs, and the signal for emergency evacuation, worn or broken wires can cause one or more of these systems to fail. Failure of the fuel shutoff valves, for example, would prevent the flight crew from stopping the flow of fuel to the engines in the event of a fire. This action is necessary to prevent damage to the wires in the bundles due to contact between the bundles and the adjacent ceiling support bracket, which could result in electrical arcing, smoke, or fire in the cabin, and failure of certain systems essential to safe flight and landing of the airplane. Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin 76733A0085, Revision 2, dated December 7, 2000, which describes, among other things, procedures for a onetime inspection to find chafing and determine adequate clearance of certain wire bundles in the ceiling panel near the main passenger door, and corrective actions. The corrective actions include, but are not limited to, repair or replacement of worn wires in the wire bundles with new wires; installation of a bracket assembly on the wire bundle support bracket for certain airplanes, installation of nut spacer plates for certain other airplanes, and rerouting of the wire bundles to provide adequate clearance between the bundles and the adjacent structure.
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 Service Bulletin and This Proposed AD

Operators should note that, although the service bulletin specifies accomplishment of the actions as soon as manpower and facilities are available, the FAA has determined that a sixmonth compliance time for accomplishment of the actions would address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the actions. In light of all of these factors, the FAA finds a sixmonth compliance time for completion of the actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Cost Impact

There are approximately 135 airplanes of the affected design in the worldwide fleet. The FAA estimates that 53 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to accomplish the proposed inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection proposed by this AD on U.S. operators is estimated to be $3,180, or $60 per airplane.

It would take approximately 2 work hours per airplane to accomplish the proposed repair or replacement, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the repair or replacement proposed by this AD on U.S. operators is estimated to be $6,360, or $120 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
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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 39AIRWORTHINESS 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 2000NM268AD.

Applicability: Model 767300 series airplanes, as listed in Boeing Alert Service Bulletin 76733A0085, Revision 2, dated December 7, 2000, certificated in any category.

Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent damage to the wires in certain wire bundles due to contact between the bundles and the adjacent ceiling support bracket, which could result in electrical arcing, smoke, or fire in the cabin, and failure of certain systems essential to safe flight and landing of the airplane, accomplish the following:
OneTime Inspection/Corrective Actions
(a) Accomplish the requirements in paragraphs (a)(1) and (a)(2) of this AD, as applicable, at the times specified.
(1) Within 6 months after the effective date of this AD: Do a onetime general visual inspection to find chafing and determine adequate clearance of the wire bundles above the F4/G2 galley, per Figure 1 or Figure 3, as applicable, of the Accomplishment Instructions of Boeing Alert Service Bulletin 76733A0085, Revision 2, dated December 7, 2000.

Note 2: For the purposes of this AD, a general visual inspection is defined as: ``A visual examination of an interior or exterior area, installation, or assembly to find obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.''
(2) If chafing and/or inadequate clearance is found: Before further flight, repair or replace damaged wires in the wire bundles; install a bracket assembly on the wire bundle support bracket; install nut spacer plates; and reroute the wire bundles away from the ceiling support bracket, as applicable, as specified by and per Figure 2 or Figure 3, as applicable, of the Accomplishment Instructions of the alert service bulletin.

Note 3: Accomplishment of the onetime inspection and corrective actions before the effective date of this AD per Boeing Alert Service Bulletin 76733A0085, dated May 11, 2000, or Revision 1, dated August 31, 2000, is considered acceptable for compliance with paragraph (a) of this AD.
Alternative Methods of Compliance
(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
Special Flight Permit
(c) Special flight permits may be issued per sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Issued in Renton, Washington, on March 5, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 015808 Filed 3801; 8:45 am] BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Elias Natsiopoulos, Aerospace Engineer, Systems and Equipment Branch, ANM130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055 4056; telephone (425) 2271279; fax (425) 2271181.