[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