[Federal Register Volume 59, Number 17 (Wednesday, January 26, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-1464]


[[Page Unknown]]

[Federal Register: January 26, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-231-AD; Amendment 39-8806; AD 94-02-08]

 

Airworthiness Directives; McDonnell Douglas Model MD-11 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain McDonnell Douglas Model MD-11 series 
airplanes. This action requires an inspection to detect chafing damage 
to certain wiring in the main avionics rack, repair or replacement of 
damaged wiring, and modification of the wiring installation. This 
amendment is prompted by a report of a chafed wire harness found on the 
main avionics rack on one airplane that resulted in arcing damage to 
the wire harness and adjacent structure. The actions specified in this 
AD are intended to prevent chafing of the main avionics rack wiring, 
which could result in arcing and a fire in the wire bundle; this could 
lead to damage to aircraft systems and loss of associated aircraft 
functions.

DATES: Effective February 10, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 10, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before March 28, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 93-NM-231-AD, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056.
    The service information referenced in this AD may be obtained from 
McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, California 
90846-0001, Attention: Business Unit Manager, Technical Publications, 
C1-HDR (54-60). This information may be examined at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at 
the Los Angeles Aircraft Certification Office, FAA, Transport Airplane 
Directorate, 3229 East Spring Street, Long Beach, California; or at the 
Office of the Federal Register, 800 North Capitol Street NW., suite 
700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Brett Portwood, Aerospace Engineer, 
Systems & Equipment Branch, ANM-132L, Los Angeles Aircraft 
Certification Office, FAA, Transport Airplane Directorate, 3229 East 
Spring Street, Long Beach, California 90806-2425; telephone (310) 988-
5347; fax (310) 988-5210.

SUPPLEMENTARY INFORMATION: Recently, one operator of McDonnell Douglas 
Model MD-11 series airplanes reported one instance of the auto ground 
spoiler failing to arm on one airplane. Investigation revealed two 
wires that had burnt in half and several charred wires on shelf 3 of 
the aft section of the main avionics rack. These wires apparently had 
chafed and shorted on the screws that attach the wire bundle trough 
assembly to the rack. Additionally, the protective tape was worn from 
the attach screw heads. The operator then conducted a fleet inspection 
and found additional wire chafing at the same location on another 
airplane. The operator also found worn protective tape (exposed screw 
heads) at various locations on the avionics racks on other airplanes. 
Chafing of the wiring in the main avionics rack, if not detected and 
corrected in a timely manner, could result in arcing and a fire in the 
wire bundle; this could lead to damage to aircraft systems and the loss 
of associated aircraft functions.
    The FAA has reviewed and approved McDonnell Douglas MD-11 Alert 
Service Bulletin A24-75, dated December 22, 1993, that describes 
procedures for performing a visual inspection to detect chafing damage 
to the wire harness located on the aft side of the main avionics rack 
on shelves 1 through 4. It also describes procedures for repairing or 
replacing damaged wiring, and modifying the wiring installation by 
bonding nylon sheets between the wire harnesses and the protective tape 
on the screw heads.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Model MD-11 series airplanes of the same type 
design, this AD is being issued to prevent chafing of the main avionics 
rack wiring, which could result in arcing and fire in the wire bundle, 
and lead to damage to aircraft systems and the subsequent loss of 
associated aircraft functions. This AD requires a detailed visual 
inspection to detect chafing damage to the wire harnesses located on 
the aft side of the main avionics rack on shelves 1 through 4. Any 
damaged wiring must be replaced or repaired prior to further flight. 
Additionally, operators are required to modify the wiring installation 
by bonding nylon sheets between the wire harnesses and the protective 
tape on the screw heads. The actions are required to be accomplished in 
accordance with the service bulletin described previously.
    This is considered interim action until final action is identified, 
at which time the FAA may consider additional rulemaking.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD 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 93-NM-231-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, may 
be obtained from the Rules Docket at the location provided under the 
caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 14 CFR part 
39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

94-02-08 McDonnell Douglas: Amendment 39-8806. Docket 93-NM-231-AD.
    Applicability: Model MD-11 series airplanes; manufacturer's 
fuselage numbers 447 through 558, inclusive; certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent chafing of the main avionics rack wiring, which could 
result in arcing and a fire in the wire bundle, damage to aircraft 
systems, and subsequent loss of associated aircraft functions, 
accomplish the following:
    (a) Within 30 days after the effective date of this AD, conduct 
a one-time detailed visual inspection to detect chafing damage to 
the wire harnesses located on the aft side of the main avionics rack 
on shelves 1 through 4, left and right sides, in accordance with 
McDonnell Douglas MD-11 Alert Service Bulletin A24-75, dated 
December 22, 1993.
    (b) If no damage is detected during the inspection required by 
paragraph (a) of this AD, prior to further flight, modify the wiring 
installation in accordance with the service bulletin.
    (c) If any damage is detected during the inspection required by 
paragraph (a) of this AD, prior to further flight, accomplish the 
requirements of paragraphs (c)(1), (c)(2), and (c)(3) of this AD in 
accordance with the service bulletin:
    (1) Repair or replace the damaged wiring;
    (2) Modify the wiring installation; and
    (3) Perform a return-to-service test of the affected wiring 
system.
    (d) 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). 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: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (e) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the airplane to a location where the 
requirements of this AD can be accomplished.
    (f) The inspection, repair, replacement, and modification shall 
be done in accordance with McDonnell Douglas MD-11 Alert Service 
Bulletin A24-75, dated December 22, 1993. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
obtained from McDonnell Douglas Alert Service Bulletin A24-75, dated 
December 22, 1993. Copies may be inspected at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or 
at the Los Angeles Aircraft Certification Office, FAA, Transport 
Airplane Directorate, 3229 East Spring Street, Long Beach, 
California; or at the Office of the Federal Register, 800 North 
Capitol Street NW., suite 700, Washington, DC.
    (g) This amendment becomes effective on February 10, 1994.

    Issued in Renton, Washington, on January 14, 1994.
John J. Hickey,
 Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-1464 Filed 1-25-94; 8:45 am]
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