[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]
BILLING CODE 4910-13-U
