[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: 94-18226]


[[Page Unknown]]

[Federal Register: July 27, 1994]


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


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-65-AD]

 

Airworthiness Directives; McDonnell Douglas Model DC-8-70 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to all McDonnell Douglas Model 
DC-8-70 series airplanes, that currently requires replacement of all 
attachment screws at the exhaust nozzle plug splice, and a check of nut 
plates for running torque and replacement of nut plates, if necessary. 
This action would require modification of the engine exhaust plug 
assemblies; when accomplished, this modification would terminate the 
need for the currently required replacement and check. This proposal is 
prompted by reports of loose or missing attachments at the splice joint 
of the engine forward and aft exhaust plugs, and loss of the rear 
exhaust plug following an engine bird strike. The actions specified by 
the proposed AD are intended to prevent reduced integrity of the engine 
exhaust plug installation, which may lead to separation of exhaust 
plugs from the airplane, and create a hazard to persons and property on 
the ground.

DATES: Comments must be received by September 9, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-65-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-65-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-65-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On January 17, 1983, the FAA issued AD 83-02-05, amendment 39-4544 
(48 FR 5539, February 7, 1983), applicable to all McDonnell Douglas 
Model DC-8-70 series airplanes, to require replacement of all 
attachment screws at the exhaust nozzle plug splice. That AD also 
requires a check of nut plates for running torque and replacement of 
nut plates not meeting the minimum run down torque of five inch-pounds. 
That action was prompted by reports of loose or missing attachment 
screws at the plug splice joint. In one reported incident, the exhaust 
plug nozzle separated from one engine while the airplane was in flight. 
The requirements of that AD are intended to prevent separation of the 
exhaust nozzle plug from the engine.
    Since the issuance of that AD, three operators have reported four 
incidents of loose or missing attachments at the splice joint of the 
engine forward and aft exhaust plugs. These discrepancies were found on 
airplanes subsequent to the accomplishment of AD 83-02-05. One operator 
reported loss of the rear exhaust plug on one airplane after the engine 
sustained a bird strike. Investigation revealed that the cause of these 
loose or missing splice joint attachments was attributed to higher 
temperatures and vibration effects of the engine exhaust.
    Operators also reported loose nuts at the forward plug-to-engine 
turbine flange attachments. The cause of these loose nuts has been 
attributed to high temperature and incompatibility of the nut threads 
with associated threaded studs.
    These conditions, if not corrected, could result in reduced 
integrity of the engine exhaust plug installation, which may lead to 
separation of exhaust plugs from the airplane, and create a hazard to 
persons and property on the ground.
    The FAA has reviewed and approved McDonnell Douglas DC-8-70 Service 
Bulletin 78-112, Revision 2, dated March 8, 1994, that describes 
procedures for modification of the engine exhaust plug assemblies. The 
modification entails replacement of existing fasteners with permanent 
fasteners having larger diameters; this will serve to strengthen the 
splice installation and minimize the possibility of loose splice joint 
fasteners. Further, this modification entails replacement of existing 
nuts with nuts that are less susceptible to the effects of higher 
temperatures and have compatible thread pitch, which minimizes the 
possibility of forward plug-to-engine turbine attachments becoming 
loose.
    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 supersede AD 83-02-05 to require modification of the 
engine exhaust plug assemblies. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously. Accomplishment of this modification would constitute 
terminating action for the currently required replacement and check.
    There are approximately 110 Model DC-8-70 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 78 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 46 work hours per airplane to accomplish 
the proposed modification, and that the average labor rate is $55 per 
work hour. Required parts would cost approximately $21,400 per 
airplane. Based on these figures, the total cost impact of the proposed 
AD on U.S. operators is estimated to be $1,866,540, or $23,930 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 removing amendment 39-4544 (48 FR 
5539, February 7, 1983), and by adding a new airworthiness directive 
(AD), to read as follows:

McDonnell Douglas: Docket 94-NM-65-AD. Supersedes AD 83-02-05, 
Amendment 39-4544.

    Applicability: All Model DC-8-70 series airplanes, certificated 
in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent reduced integrity of the engine exhaust plug 
installation, which may lead to separation of exhaust plugs from the 
airplane, and create a hazard to persons and property on the ground, 
accomplish the following:
    (a) Within 300 flight hours after February 7, 1983 (the 
effective date of AD 83-02-05, amendment 39-4544), accomplish the 
procedures specified in paragraphs (a)(1) and (a)(2) of this AD in 
accordance with McDonnell Douglas DC-8-70 Alert Service Bulletin 
A78-107, dated November 30, 1982; McDonnell Douglas DC-8-70 Service 
Bulletin 78-107, dated January 16, 1984; or McDonnell Douglas DC-8-
70 Service Bulletin 78-107, Revision 1, dated June 12, 1984.
    (1) Replace all NAS560XK4-5 screws with NAS560XK4-4 screws at 
the exhaust nozzle plug splice.
    (2) Check nut plates for running torque and replace all nut 
plates not meeting the minimum run down torque of five inch-pounds.
    (b) Within 24 months after the effective date of this AD, modify 
the engine exhaust plug assemblies in accordance with McDonnell 
Douglas DC-8-70 Service Bulletin 78-112, Revision 2, dated March 8, 
1994. Accomplishment of this modification constitutes terminating 
action for the replacement and check requirements of paragraph (a) 
of this AD.
    (c) 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.

    (d) Special flight permits may be issued in accordance with 
Secs.  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 20, 1994.
Darrell M. Pederson, Acting Manager,
Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 94-18226 Filed 7-26-94; 8:45 am]
BILLING CODE 4910-13-U