Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series Airplanes and Model MD-88 Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-87-AD; Amendment 39-9090; AD 94-25-06]

Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series

Airplanes and Model MD-88 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain Model DC-9-80 series airplanes and Model MD-88

airplanes, that requires modification of the engine nose cowls. This

amendment is prompted by several in-flight incidents in which the

engine nose cowl separated or nearly separated from the airplane. The

actions specified by this AD are intended to prevent separation of the

engine nose cowl from the airplane during severe vibration of the

engine.

DATES: Effective January 17, 1995.

The incorporation by reference of certain publications listed in

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

of January 17, 1995.

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, 3960 Paramount Boulevard, Lakewood,

California 90712; 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, 3960 Paramount Boulevard,

Lakewood, California 90712; telephone (310) 627-5245; fax (310) 627-

5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to include an airworthiness

directive (AD) that is applicable to certain Model DC-9-80 series

airplanes and Model MD-88 airplanes series airplanes was published in

the Federal Register on July 27, 1994 (59 FR 38147). That action

proposed to require modification of the left and right engine nose

cowls.

Interested persons have been afforded an opportunity to participate

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

the comments received.

One commenter supports the propose rule.

Several commenters request that the compliance time for the

accomplishment of the modification be extended from the proposed 8

months to 12 or 18 months. These commenters state that they would have

to special schedule their fleet of airplanes to accomplish this

modification within the proposed compliance time. This would entail

considerable additional expenses and schedule disruptions. The FAA

concurs. The FAA's intent was that the modification be accomplished

during a regularly scheduled maintenance for the majority of the

affected fleet, when the airplanes would be located at a base where

special equipment and trained personnel would be readily available, if

necessary. Based on the information supplied by the commenters, the FAA

now recognizes that 12 months corresponds more closely to the interval

representative of most of the affected operators' normal maintenance

schedules. Paragraph (a) of the final rule has been revised to reflect

a compliance time of 12 months. The FAA does not consider that this

extension of an additional 4 months for compliance will adversely

affect safety.

Two commenters state that, during accomplishment of the

modification, they found an interference condition on the engine cowls

being modified that prevents installation of bolt heads facing forward.

One commenter states that the final rule of this AD should not be

released until the McDonnell Douglas MD-80 Alert Service Bulletin A71-

61 is revised to correct procedures relative to this interference

condition. The FAA infers from these commenters that they would like

the proposed rule to be revised to cite the latest revision of

McDonnell Douglas MD-80 Alert Service A71-61. The FAA concurs. Since

issuance of the proposed rule, the FAA has reviewed and approved

Revision 1, of McDonnell Douglas Alert Service Bulletin, dated October

4, 1994. Revision 1 allows the installation of bolts from the engine

flange side when interference with the Hi-Lok bolts exist. The FAA has

revised paragraph (a) of the final rule to reflect the latest revision

to the alert service bulletin as an additional source of service

information.

The FAA has recently reviewed the figures it has used over the past

several years in calculating the economic impact of AD activity. In

order to account for various inflationary costs in the airline

industry, the FAA has determined that it is necessary to increase the

labor rate used in these calculations from $55 per work hour to $60 per

work hour. The economic impact information, below, has been revised to

reflect this increase in the specified hourly labor rate.

As a result of recent communications with the Air Transport

Association (ATA) of America, the FAA has learned that 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. Under these

circumstances, at least one operator appears to have incorrectly

assumed that its airplane was not subject to the AD. On the contrary,

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

added to the final rule to clarify this requirement.

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 changes previously

described. The FAA has determined that these changes will neither

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

the AD.

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 will be affected by this AD, that it will take approximately 6

work hours per airplane to accomplish the required actions, and that

the average labor rate is $60 per work hour. Required parts will cost

approximately $100 per airplane. Based on these figures, the total cost

impact of the AD on U.S. operators is estimated to be $248,400, or $460

per airplane.

The FAA has been advised that 74 U.S.-registered airplanes have

been modified in accordance with the requirement of this AD. Therefore,

the future economic cost impact of this rule on U.S. operators is now

only $214,360.

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 adding the following new

airworthiness directive:

94-25-06 McDonnell Douglas: Amendment 39-9090. 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, Revision 1, dated October 4, 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 prevent the engine nose cowl separating from the airplane

during severe engine vibration, accomplish the following: -

(a) Within 12 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, or

Revision 1, dated October 4, 1994.

-Note 2: 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 3: 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

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. -

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

Douglas MD-80 Alert Service Bulletin A71-61, dated May 18, 1994, or

McDonnell Douglas MD-80 Alert Service Bulletin, Revision 1, dated

October 4, 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 the FAA, Transport Airplane Directorate, Los Angeles Aircraft

Certification Office, 3960 Paramount Boulevard, Lakewood, California

90712; or at the Office of the Federal Register, 800 North Capitol

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

(e) This amendment becomes effective on January 17, 1995.

Issued in Renton, Washington, on December 2, 1994.

James V. Devany,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-30144 Filed 12-14-94; 8:45 am]

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