Airworthiness Directives; McDonnell Douglas Model DC-10 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-22-AD]

Airworthiness Directives; McDonnell Douglas Model DC-10 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing

airworthiness directive (AD), applicable to all McDonnell Douglas Model

DC-10-10, -10F, -30, and -30F series airplanes, that currently requires

inspections to detect ice or snow accumulation on top of the fuselage

and in the inlet of the number 2 engine, and removal of ice and snow

accumulation. This action would add certain airplanes to the

applicability of the rule and would limit the inspection requirement to

only a certain group of airplanes. This proposal is prompted by the

development of improved fan blades on certain engines and the

identification of additional airplanes that are subject to the unsafe

condition. The actions specified by the proposed AD are intended to

minimize damage to the number 2 engine due to ingestion of ice and

snow.

DATES: Comments must be received by September 7, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 94-NM-22-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, Department 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: Raymond Vakili, 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) 988-5262; 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 rule must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 94-NM-22-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-22-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

The FAA issued AD 75-04-11, amendment 39-2094, applicable to all

McDonnell Douglas Model DC-10-10, -10F, -30, and -30F series airplanes,

to require inspection to detect ice and snow accumulation on top of the

fuselage and in the inlet of the number 2 engine, and removal of ice

and snow. That action was prompted by reports from operators of Model

DC-10 series airplanes that ice was ingested into the number 2 engine.

In these incidents, the number 2 engine on airplanes that had been

parked during icing conditions ingested ice and sustained damage

shortly after the engine was started. The requirements of that AD are

intended to prevent damage to the number 2 engine due to ingestion of

ice and snow.

Since the issuance of that AD, the General Electric (GE) Company

has issued design changes to the GE Model CF6 series engines that

include replacement of the gundrilled fan blades (that is, blades

having radial lightening holes) with solid blades. The FAA has

determined that in the event of excessive ice ingestion, these solid

fan blades are less likely to result in an uncontained failure.

Therefore, the FAA finds that the applicability of the existing rule

must be revised to exclude airplanes equipped with these engines and

fan blades from the AD requirement to inspect to detect ice and snow on

top of the fuselage and in the inlet of the number 2 engine.

(Similarly, Model DC-10-40 series airplanes equipped with Pratt and

Whitney Model JT9D series engines having solid fan blades were excluded

from the requirements of AD 75-04-11 since they, too, are not subject

to the unsafe condition.)

Further, since the issuance of AD 75-04-11, the FAA has determined

that Model DC-10-15 series airplanes and Model KC-10A (military)

airplanes are subject to the addressed unsafe condition since they

utilize the same gundrilled blade engines as Model DC-10-10, -10F, -30,

and -30F series airplanes, which are subject to the requirements of AD

75-04-11 and are also susceptible to ice and snow ingestion into the

number 2 engine. Therefore, the FAA finds that the applicability of the

existing rule must be expanded to include Model DC-10-15 series

airplanes and Model KC-10A (military) airplanes.

Ingestion of ice and snow into the number 2 engine could result in

damage to that 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 supersede AD 75-04-11 to require inspections to

detect ice and snow accumulation on top of the fuselage and in the

inlet of the number 2 engine, and removal of ice and snow. The

applicability of this proposal would be revised to include all Model

DC-10-10, -10F, -30, -30F, and -15 series airplanes and Model KC-10A

(military) airplanes, equipped with GE Model CF6 series turbofan

engines having gundrilled blades.

Additionally, paragraph (b) of AD 75-04-11, which relates to making

``appropriate maintenance record entries'' after accomplishing the

requirements of the AD, has not been reiterated in this proposed AD

since those requirements are redundant of the requirements contained in

sections 43.9 (``Content, form, and disposition of maintenance,

preventive maintenance, rebuilding, and alteration records'') and 43.11

(``Content, form, disposition of records for inspections . . .'') of

the Federal Aviation Regulations (14 CFR 43.9 and 43.11). As such,

operators are not relieved from the requirement to make appropriate

entries in their maintenance records.

There are approximately 379 McDonnell Douglas Model DC-10-10, -10F,

-30, -30F, and -15 series airplanes and Model KC-10A (military)

airplanes of the affected design in the worldwide fleet. The FAA

estimates that 226 airplanes of U.S. registry would be affected by this

proposed AD.

The inspections that were previously required by AD 75-04-11, and

retained in this AD, take approximately 1 work hour per airplane to

accomplish, at an average labor rate of $55 per work hour. Based on

these figures, the total cost impact of the inspection requirement on

U.S. operators is estimated to be $12,430, or $55 per airplane, per

inspection. This proposal would only add the cost of inspections for

the operators of Model KC-10A (military) airplanes. Currently, there

are no Model DC-10-15 series airplanes of U.S. registry that would be

affected by this proposal.

For operators of Model DC-10-10, -10F, -30, and -30F series

airplanes having all solid fan blades in the number 2 engine position,

the economic burden would be reduced since the previous requirement to

inspect these airplanes in accordance with the existing AD would be

eliminated by this proposal. However, this does not relieve operators

of the responsibility to comply with the requirements of sections

91.527 (``Operating in icing conditions'') and 121.629 (``Operation in

icing conditions''--air carriers) of the Federal Aviation Regulations

(14 CFR 91.527 and 121.629).

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 39-2094, and by

adding a new airworthiness directive (AD), to read as follows:

McDonnell Douglas: Docket 94-NM-22-AD. Supersedes AD 75-04-11,

Amendment 39-2094.

Applicability: Model DC-10-10, -10F, -30, -30F, and -15 series

airplanes, and Model KC-10A (military) airplanes, on which the

number 2 engine is a General Electric Model CF6 series turbofan

engine having one or more gundrilled fan blades installed, including

but not limited to part numbers 9010M33 and 9137M39; certificated in

any category.

Compliance: Required as indicated, unless accomplished

previously. To prevent possible damage to the number 2 engine due to

ingestion of ice and snow, accomplish the following:

(a) As of the effective date of this AD, prior to starting the

number 2 engine on any airplane that has been parked during icing

conditions (freezing rain, snow, sleet) for any period of time

during which ice or snow may have accumulated on the airplane in the

area of the number 2 engine, inspect to detect ice and snow

accumulation on top of the fuselage and in the inlet of the number 2

engine. If ice or snow accumulation is found, prior to further

flight, remove the ice or snow accumulation.

Note 1: Guidelines for inspection and safeguarding the aircraft

are contained in these documents:

Douglas All Operators Letter (AOL) 10-546, dated January 11, 1974

Douglas AOL 10-673, dated August 7, 1974

DC-10 Airplane Maintenance Manual, Chapter 12-31-01

(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 12, 1994.

S.R. Miller,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-17327 Filed 7-15-94; 8:45 am]

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