[Federal Register Volume 59, Number 243 (Tuesday, December 20, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31183]
[[Page Unknown]]
[Federal Register: December 20, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-194-AD]
Airworthiness Directives; McDonnell Douglas Model DC-9, DC-9-80,
and C-9 (Military) Series Airplanes, and Model MD-88 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
DC-9, DC-9-80, and C-9 (Military) series airplanes, and Model MD-88
airplanes. This proposal would require repetitive replacement of the
emergency power switch in the overhead switch panel with a new switch.
This proposal is prompted by a report of heavy smoke in the cockpit
coming from the overhead switch panel on a Model DC-9-81 series
airplane. The actions specified by the proposed AD are intended to
ensure replacement of the emergency power switch when it has reached
its maximum life limit; an emergency power switch that is not replaced
could fail and lead to a short in the electrical circuit, which could
result in a fire in the overhead switch panel and smoke in the cockpit.
DATES: Comments must be received by January 31, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-194-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, P.O. Box 1771, Long Beach,
California 90801-1771, Attention: Business Unit Manager, Technical
Administrative Support, Dept. L51, M.C. 2-98. 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 90712.
FOR FURTHER INFORMATION CONTACT: Elvin Wheeler, Aerospace Engineer,
Systems and Equipment Branch, ANM-132L, FAA, Transport Airplane
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount
Boulevard, Lakewood, California 90712; telephone (310) 988-5344; fax
(310) 988-5210.
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 94-NM-194-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. 94-NM-194-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received a report of heavy smoke in the cockpit coming
from the overhead switch panel on a McDonnell Douglas Model DC-9-81
(MD-81) series airplane. Investigation revealed that the fire had
originated in the area of the emergency power switch in the overhead
switch panel. Further investigation, conducted by Mason Electric
Company (the manufacturer of the emergency power switch), revealed that
the emergency power switch, upon exceeding 10,000 switch cycles (off-
to-on-to-off) can fail due to wear or overstress. If not replaced in a
timely manner, the emergency power switch could fail and lead to a
short in the electrical circuit, which could result in a fire in the
overhead switch panel and smoke in the cockpit.
The FAA has reviewed and approved McDonnell Douglas DC-9 Service
Bulletin 24-150, dated March 28, 1994, which describes procedures for
repetitively replacing the emergency power switch in the overhead
switch panel with a new switch at regular intervals.
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 repetitively replacing the emergency power
switch in the overhead switch panel with a new switch at regular
intervals. The actions would be required to be accomplished in
accordance with the service bulletin described previously.
As a result of recent communications with the Air Transport
Association (ATA) of America, the FAA has learned that, in general,
some operators may misunderstand the legal effect of AD's on airplanes
that are identified in the applicability provision of the AD, but that
have been altered or repaired in the area addressed by the AD. The FAA
points out that all airplanes identified in the applicability provision
of an AD are legally subject to the AD. If an airplane has been altered
or repaired in the affected area in such a way as to affect compliance
with the AD, the owner or operator is required to obtain FAA approval
for an alternative method of compliance with the AD, in accordance with
the paragraph of each AD that provides for such approvals. A note has
been included in this notice to clarify this requirement.
There are approximately 1,990 Model DC-9, DC-9-80, and C-9
(Military) series airplanes and Model MD-88 airplanes of the affected
design in the worldwide fleet. The FAA estimates that 992 airplanes of
U.S. registry would be affected by this proposed AD, that it would take
approximately 2 work hours per airplane to accomplish the proposed
actions, and that the average labor rate is $60 per work hour. Required
parts would cost approximately $1,434 per airplane. Based on these
figures, the total cost impact of the proposed AD on U.S. operators is
estimated to be $1,541,568, or $1,554 per airplane, per replacement
cycle.
The total 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.
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. 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:
McDonnell Douglas: Docket 94-NM-194-AD.
Applicability: Model DC-9-10, -20, -30, -40, and -50 series
airplanes; Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83),
and DC-9-87 (MD-87) series airplanes; Model MD-88 airplanes; and C-9
(Military) series airplanes; as listed in McDonnell Douglas DC-9
Service Bulletin 24-150, dated March 28, 1994; 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 use the authority
provided in paragraph (b) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition; or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To ensure replacement of the emergency power switch that have
reached the maximum life limit, accomplish the following:
(a) Prior to the accumulation of 3 years time-in-service on the
emergency power switch in the overhead switch panel, or within 12
months after the effective date of this AD, whichever occurs later,
replace the emergency power switch with a new switch, in accordance
with McDonnell Douglas DC-9 Service Bulletin 24-150, dated March 28,
1994. Thereafter, replace the emergency power switch at intervals
not to exceed the accumulation of 3 years time-in-service on the
switch.
(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 December 14, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-31183 Filed 12-19-94; 8:45 am]
BILLING CODE 4910-13-U
