[Federal Register Volume 59, Number 200 (Tuesday, October 18, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-25694]


[[Page Unknown]]

[Federal Register: October 18, 1994]


-----------------------------------------------------------------------


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-144-AD]

 

Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -
30, -40, and -50 Series Airplanes, and Model C-9 (Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas Model 
DC-9-10, -20, -30, -40, and -50 series airplanes, and Model C-9 
(military) airplanes. This proposal would require replacement of the 
engine nose cowl attaching bolts and the installation of bearing plates 
on the nose cowl attach ring. This proposal is prompted by incidents in 
which the nose cowl separated from the airplane due to the elongation 
and/or breakout of the nose cowl's attachment ring holes, and failure 
of the attaching bolts. The actions specified by the proposed AD are 
intended to prevent separation of the engine nose cowl from the 
airplane, which could result in damage to the airplane structure or 
could present a hazard to persons or property on the ground.

DATES: Comments must be received by December 13, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-144-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, Los Angeles Aircraft 
Certification Office, Transport Airplane Directorate, 3229 East Spring 
Street, Long Beach, California.

FOR FURTHER INFORMATION CONTACT: Robert Baitoo, Aerospace Engineer, 
Propulsion Branch ANM-140L, FAA, Los Angeles Aircraft Certification 
Office, Transport Airplane Directorate, 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-144-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-144-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion -

    The FAA has received reports of five incidents, involving McDonnell 
Douglas Model DC-9 series airplanes, in which the engine nose cowl 
separated from the airplane. Investigation revealed that these 
incidents of separation of the nose cowls have occurred following 
severe engine vibration that was caused by failures of the first stage 
or second stage fan blades. The cause of the separations has been 
attributed to elongation and/or breakout of the engine nose cowl's 
attachment ring holes. Additionally, in some cases, the attach bolts 
had failed. This condition, if not corrected, could lead to separation 
of the engine nose cowl from the airplane, which could result in damage 
to the airplane fuselage or other structure, or could present a hazard 
to persons or property on the ground. -
    The FAA has reviewed and approved McDonnell Douglas DC-9 Alert 
Service Bulletin A71-63, dated July 21, 1994, which describes 
procedures for replacement of the left and right engine nose cowl 
attaching bolts with new bolts of increased strength. It also describes 
procedures for adding bearing plates on the nose cowl attach ring. 
These actions will minimize the possibility of the engine nose cowl 
separating from the airplane. -
    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 replacement of the nose cowl attaching bolts 
and the installation of bearing plates on the nose cowl attach ring. 
The actions would be required to be accomplished in accordance with the 
service bulletin described previously.-
    There are approximately 892 Model DC-9-10, -20, -30, -40, and -50 
series airplanes, and Model C-9 (military) airplanes of the affected 
design in the worldwide fleet. The FAA estimates that 557 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 $1,200 per airplane. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $852,210, or $1,530 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-144-AD.

     -Applicability: Model DC-9-10, -20, -30, -40, and -50 series 
airplanes, and Model C-9 (military) airplanes; as listed in 
McDonnell Douglas DC-9 Alert Service Bulletin A71-63, dated July 21, 
1994; certificated in any category. -
    Compliance: Required as indicated, unless accomplished 
previously. -
    To prevent separation of the engine nose cowl from the airplane, 
accomplish the following: -
    (a) Within 12 months after the effective date of this AD, 
replace the left and right engine nose cowl attaching bolts and 
install bearing plates, in accordance with McDonnell Douglas DC-9 
Alert Service Bulletin A71-63, dated July 21, 1994. -
    (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: 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 October 12, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-25694 Filed 10-17-94; 8:45 am]
BILLING CODE 4910-13-U