[Federal Register Volume 59, Number 143 (Wednesday, July 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18284]


[[Page Unknown]]

[Federal Register: July 27, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-87-AD]

 

Airworthiness Directives; McDonnell Douglas Model DC-9-80 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 Model DC-9-80 series 
airplanes and Model MD-88 airplanes. This proposal would require 
modification of the engine nose cowl. This proposal is prompted by 
several in-flight incidents in which the engine nose cowl separated or 
nearly separated from the airplane. The actions specified by the 
proposed AD are intended to prevent separation of the engine nose cowl 
from the airplane during severe vibration of the engine.

DATES: Comments must be received by September 12, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-87-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, 3229 East Spring Street, 
Long Beach, California.

FOR FURTHER INFORMATION CONTACT: Robert Baitoo, Aerospace Engineer, 
Propulsion Branch, ANM-141L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3229 East Spring Street, Long 
Beach, California 90806-2425; telephone (310) 988-5245; 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-87-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-87-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of several in-flight incidents that 
have occurred on McDonnell Douglas Model DC-9-80 series airplanes in 
which the engine nose cowl separated or nearly separated from these 
airplanes. Investigation revealed that these separations occurred 
following severe vibration of the engine due to failures of the first 
stage fan blade. The cause of these separations has been attributed to 
loose or missing attachment bolts of the engine nose cowl. This 
condition, if not corrected, could result in separation of the engine 
nose cowl from the airplane during severe vibration of the engine.
    The FAA has reviewed and approved McDonnell Douglas MD-80 Alert 
Service Bulletin A71-61, dated May 18, 1994, which describes procedures 
for modification of the left and right engine nose cowls. This 
modification entails removal of attachment bolts and nutplates, 
replacement of nutplates with self-locking nuts and washers on the 
engine ``A'' flange, and reversal of attachment bolt direction 
(bolthead facing forward). This modification will ensure the integrity 
of the nose cowl attachment assembly so as to minimize the possibility 
of separation of the engine nose cowl from the airplane during severe 
vibration of the engine.
    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 modification of the left and right engine 
nose cowls. The actions would be required to be accomplished in 
accordance with the alert service bulletin described previously.
    There are approximately 1,062 McDonnell Douglas Model DC-9-80 
series airplanes and Model MD-88 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 540 airplanes of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 6 work hours per airplane to accomplish the proposed 
actions, and that the average labor rate is $55 per work hour. Required 
parts would cost approximately $100 per airplane. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $232,200, or $430 per airplane.
    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-87-AD.

    Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 
(MD-83), and DC-9-87 (MD-87) series airplanes and Model MD-88 
airplanes; as listed in McDonnell Douglas MD-80 Alert Service 
Bulletin A71-61, dated May 18, 1994; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the engine nose cowl separating from the airplane 
during severe engine vibration, accomplish the following:
    (a) Within 8 months after the effective date of this AD, modify 
the left and right engine nose cowls in accordance with McDonnell 
Douglas MD-80 Alert Service Bulletin A71-61, dated May 18, 1994.

    Note 1: Modification in accordance with either Figure 1, Figure 
2, or Figure 3 of the alert service bulletin is acceptable for 
compliance with this paragraph.

    (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 July 21, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-18284 Filed 7-26-94; 8:45 am]
BILLING CODE 4910-13-U