Airworthiness Directives; McDonnell Douglas Model MD-11 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-171-AD]

RIN 2120-AA64

Airworthiness Directives; McDonnell Douglas Model MD-11 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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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 detailed

visual inspection of the wire bundle installation behind the first

observer's station to detect damaged or chafed wires; and corrective

action, if necessary. This proposal is prompted by a report indicating

that the wire bundle contained in the feedthrough behind the first

observer's station was contacting the bottom portion of the

feedthrough. The actions specified by the proposed AD are intended to

prevent such contact, which could cause cable

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chafing, electrical arcing, smoke, or fire in the cockpit.

DATES: Comments must be received by December 13, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-114,

Attention: Rules Docket No. 99-NM-171-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, Technical Specialist,

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-171-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-171-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 that the wire bundle contained in the feedthrough

behind the first observer's station was contacting with the bottom

portion of the feedthrough. This incident was found on a Model MD-11

series airplane during a McDonnell Douglas production line check. The

contact has been attributed to a design deficiency of the wire bundle

support clamp installation at the first observer's station. The design

deficiency led to excessive preloading of the support clamp and bracket

during manufacturing, which caused the clamp to rotate. This condition,

if not corrected, could allow the wire bundle contained in the

feedthrough to contact the bottom of the feedthrough, which could cause

cable chafing, electrical arcing, smoke, or fire in the cockpit.

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 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 MD11-24A041, Revision 01, dated April 26, 1999, which

describes procedures for a one-time detailed visual inspection of the

wire bundle installation behind the first observer's station to detect

damaged or chafed wires; and repair of the wires and revision of the

wire bundle support clamp installation at the observer's station, if

necessary. 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.

Cost Impact

There are approximately 63 airplanes of the affected design in the

worldwide fleet. The FAA estimates that 12 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 AD, 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

$720, or $60 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

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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 99-NM-171-AD.

Applicability: Model MD-11 series airplanes, as listed in

McDonnell Douglas Alert Service Bulletin MD11-24A041, Revision 01,

dated April 26, 1999; 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 the wire bundle contained in the feedthrough from

contacting the bottom of the feedthrough which could cause cable

chafing, electrical arcing, and smoke or fire in the cockpit,

accomplish the following:

Inspection and Modification

(a) Within 1 year after the effective date of this AD, perform a

one-time detailed visual inspection of the wire bundle installation

behind the first observer's station to detect damaged or chafed

wires, in accordance with McDonnell Douglas Alert Service Bulletin

MD11-24A041, Revision 01, dated April 26, 1999.

Note 2: For the purposes of this AD, a detailed inspection is

defined as: ``An intensive visual examination of a specific

structural area, system, installation, or assembly to detect damage,

failure, or irregularity. Available lighting is normally

supplemented with a direct source of good lighting at intensity

deemed appropriate by the inspector. Inspection aids such as mirror,

magnifying lenses, etc., may be used. Surface cleaning and elaborate

access procedures may be required.''

(1) For airplanes identified as Group 1 in the service bulletin:

Accomplish paragraph (a)(1)(i) or (a)(1)(ii) of this AD, as

applicable.

(i) If no damaged or chafed wire is found, no further action is

required by this AD.

(ii) If any damaged or chafed wire is found, prior to further

flight, repair in accordance with the service bulletin;

(2) For airplanes identified as Group 2 in the service bulletin:

Accomplish paragraph (a)(2)(i) or (a)(2)(ii) of this AD, as

applicable.

(i) If no damaged or chafed wire is found, within 1 year after

the effective date of this AD, revise the wire bundle support clamp

installation at the observer's station in accordance with the

service bulletin.

(ii) If any damaged or chafed wire is found, prior to further

flight, repair the wiring, and revise the wire bundle support clamp

installation at the observer's station in accordance with the

service bulletin.

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, 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 3: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Los Angeles ACO.

Special Flight Permits

(c) Special flight permits may be issued in accordance with

Secs. 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 October 20, 1999.

D.L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-27942 Filed 10-26-99; 8:45 am]

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