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

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-65-AD; Amendment 39-9056; AD 94-22-07]

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

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes 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

amendment requires modification of the engine exhaust plug assemblies

as terminating action for the currently required replacement and check.

This amendment 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 this 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: Effective December 12, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of December 12, 1994.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration (FAA), Transport

Airplane Directorate, Rules Docket, 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; or at the Office of the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

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: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) by superseding AD 83-02-05,

amendment 39-4544 (48 FR 5539, February 7, 1983), which is applicable

to all McDonnell Douglas Model DC-8-70 series airplanes, was published

in the Federal Register on July 27, 1994 (59 FR 38144). The action

proposed to require 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. The action also proposed to

require modification of the engine exhaust plug assemblies; when

accomplished, this modification would terminate the need for the

currently required replacement and check.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the two comments received.

One commenter supports the proposed rule.

One commenter requests that the compliance time for the

accomplishment of the modification be extended from the proposed 24

months to 60 months. This commenter states that it would have to

procure additional spare engines and would need to special schedule its

fleet of airplanes to accomplish this modification within the proposed

compliance time. This would entail considerable expense over what was

estimated in the FAA's cost impact analysis. The commenter indicates

that a compliance time of 60 months would allow the modification to be

accomplished during regularly scheduled maintenance, thereby

eliminating any additional expenses.

The FAA does not concur. In developing an appropriate compliance

time for this action, the FAA considered the safety implications, parts

availability, and the practical aspect of installing the required

modification during normal maintenance schedules. In light of this, the

FAA does not consider it appropriate to change the compliance time for

all operators based on the unique circumstances of an individual

operator. On the other hand, paragraph (c) of the AD provides that an

individual may request an adjustment of compliance time that provides

an acceptable level of safety, and this would be the appropriate means

for the commenter to seek the requested relief.

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule with the change previously

described. The FAA has determined that this change will neither

increase the economic burden on any operator nor increase the scope of

the AD.

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 will be affected by this AD, that it will

take approximately 46 work hours per airplane to accomplish the

required modification, and that the average labor rate is $55 per work

hour. Required parts will cost approximately $21,400 per airplane.

Based on these figures, the total cost impact of the 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

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted.

The regulations adopted herein will 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 final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it may be obtained

from the Rules Docket at the location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends 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), amendment 39-9056, to read as follows:

94-22-07 McDonnell Douglas: Amendment 39-9056. 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

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.

(e) The modification shall be done in accordance with McDonnell

Douglas DC-8-70 Service Bulletin 78-112, Revision 2, dated March 8,

1994. This incorporation by reference was approved by the Director

of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR

part 51. Copies 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. Copies may be inspected at the FAA, Transport Airplane

Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at FAA,

Transport Airplane Directorate, Los Angeles Aircraft Certification

Office, 3229 East Spring Street, Long Beach, California 90806-2425;

or at the Office of the Federal Register, 800 North Capitol Street,

NW., suite 700, Washington, DC.

(f) This amendment becomes effective on December 12, 1994.

Issued in Renton, Washington, on October 25, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-26875 Filed 11-9-94; 8:45 am]

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