[Federal Register Volume 62, Number 32 (Tuesday, February 18, 1997)]
[Proposed Rules]
[Pages 7182-7184]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-3841]


-----------------------------------------------------------------------


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-283-AD]
RIN 2120-AA64


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 a one-time 
inspection to detect riding, chafing, or damage of the wire bundles 
adjacent to the disconnect panel bracket of the observer's station. The 
proposed AD also would require repair or replacement of damaged wires 
with new or serviceable wires; installation of anti-chafing sleeving on 
the wire bundles, if necessary; and installation of grommet along the 
entire upper aft edge of the disconnect panel bracket. This proposal is 
prompted by a report indicating that the circuit breakers tripped on a 
Model MD-11 series airplane due to inflight arcing behind the avionics 
circuit breaker panel as a result of chafing of the wire bundles 
adjacent to the disconnect panel bracket assembly. The actions 
specified by the proposed AD are intended to detect and correct such 
chafing, which could result in a fire in the wire bundles and smoke in 
the cockpit.

DATES: Comments must be received by March 28, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-283-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 McDonnell Douglas Corporation, 3855 Lakewood Boulevard, 
Long Beach, California 90846, Attention: Technical Publications 
Business Administration, Department C1-L51 (2-60). This information may 
be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

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; telephone (310) 627-5347; fax 
(310) 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.

[[Page 7183]]

    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 96-NM-283-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-103, Attention: Rules 
Docket No. 96-NM-283-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA received a report indicating that the circuit breakers 
tripped on a Model MD-11 series airplane during flight due to arcing 
behind the avionics circuit breaker panel. Investigation revealed that 
the arcing was caused by chafing of the wire bundles adjacent to the 
disconnect panel bracket assembly. Such chafing, if not detected and 
corrected, could result in a fire in the wire bundles and smoke in the 
cockpit.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas Service 
Bulletin MD11-24-111, dated December 3, 1996. The service bulletin 
describes procedures for a one-time inspection to detect riding, 
chafing, or damage of the wire bundles adjacent to the disconnect panel 
bracket of the observer's station. The service bulletin also describes 
procedures for repair or replacement of damaged wires with new or 
serviceable wires; installation of anti-chafing sleeving on the wire 
bundles, if necessary; and installation of grommet along the entire 
upper aft edge of the disconnect panel bracket. Accomplishment of the 
installations will minimize potential arcing, wiring damage, and 
resultant loss of aircraft systems.

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 a one-time inspection to detect riding, 
chafing, or damage of the wire bundles adjacent to the disconnect panel 
bracket of the observer's station. The proposed AD also would require 
repair or replacement of damaged wires with new or serviceable wires; 
installation of anti-chafing sleeving on the wire bundles, if 
necessary; and installation of grommet along the entire upper aft edge 
of the disconnect panel bracket. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously.

Cost Impact

    There are approximately 86 McDonnell Douglas Model MD-11 series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 45 airplanes of U.S. registry would be affected by this 
proposed AD, that it would take approximately 3 work hours per airplane 
to accomplish the proposed actions, and that the average labor rate is 
$60 per work hour. The cost for required parts would be negligible. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $8,100, or $180 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 substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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:

McDonnell Douglas: Docket 96-NM-283-AD.

    Applicability: Model MD-11 series airplanes, as listed in 
McDonnell Douglas Service Bulletin MD11-24-111, dated December 3, 
1996; 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 detect and correct chafing of the wire bundles adjacent to 
the disconnect panel bracket assembly and consequent inflight arcing 
behind the avionics circuit breaker, which could result in a fire in 
the wire bundles and smoke in the cockpit, accomplish the following:
    (a) Within 6 months after the effective date of this AD: Perform 
a one-time inspection to detect riding, chafing, or damage of the 
wire bundles adjacent to the disconnect panel bracket of the 
observer's station, in accordance with McDonnell Douglas Service 
Bulletin MD11-24-111, dated December 3, 1996.
    (1) Condition 1. If any riding or chafing is found, and if any 
damage is found: Prior to further flight, repair or replace any 
damaged wires with new or serviceable wires; install anti-chafing 
sleeving on the wire bundles; and install a grommet along the entire 
upper aft edge of the disconnect panel bracket; in accordance with 
the service bulletin.
    (2) Condition 2. If any riding or chafing is found, but no 
damage is found: Prior to further flight, install anti-chafing 
sleeving on the wire bundles, and install a grommet along the entire 
upper aft edge of the

[[Page 7184]]

disconnect panel bracket, in accordance with the service bulletin.
    (3) Condition 3. If no riding, chafing, or damage is found: 
Prior to further flight, install a protective grommet along the 
entire upper aft edge of the disconnect panel bracket in accordance 
with the service bulletin.
    (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, Los Angeles Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Los Angeles ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (c) Special flight permits may be issued in accordance with 
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 February 10, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-3841 Filed 2-14-97; 8:45 am]
BILLING CODE 4910-13-U