Airworthiness Directives; Garrett Turbine Engine Company ATF3 Series Turbofan Engines

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-ANE-39; Amendment 39-9066; AD 94-23-04]

Airworthiness Directives; Garrett Turbine Engine Company ATF3

Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

applicable to Garrett Turbine Engine Company ATF3 series turbofan

engines, that requires a one-time inspection for cracks of the curvic

and bore area of the high pressure turbine (HPT) rotor assembly disk,

and replacement, if necessary, with a serviceable disk. This amendment

is prompted by several reports of cracks discovered during routine

inspections of HPT rotor assembly disks. The actions specified by this

AD are intended to prevent an uncontained failure of the HPT rotor

assembly disk.

DATES: Effective on February 6, 1995.

The incorporation by reference of certain publications listed in

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

of February 6, 1995.

ADDRESSES: The service information referenced in this AD may be

obtained from AlliedSignal Propulsion Engines, Aviation Services

Division, Data Distribution, Dept. 64-3/2102-1M, P.O. Box 29003,

Phoenix, AZ 85038-9003. This information may be examined at the Federal

Aviation Administration (FAA), New England Region, Office of the

Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA;

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

NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Joseph Costa, Aerospace Engineer, Los

Angeles Aircraft Certification Office, FAA, Transport Airplane

Directorate, 3229 East Spring Street, Long Beach, CA 90806-2425;

telephone (310) 988-5246; fax (310) 988-5210.

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 Garrett Turbine Engine Company

Model ATF3-6 and -6A turbofan engines was published in the Federal

Register on February 11, 1994 (59 FR 6603). That action proposed to

require a one-time inspection for cracks of the curvic and bore area of

high pressure turbine (HPT) rotor assembly disks listed by serial

number in Table 1 of Allied-Signal Aerospace Company, Garrett Engine

Division, Alert Service Bulletin (ASB) No. ATF3-A72-6184, Revision 1,

dated January 11, 1993.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. No comments were received on the

proposal or the Federal Aviation Administration's (FAA) determination

of the cost to the public. The FAA has determined that air safety and

the public interest require the adoption of the rule as proposed.

There are approximately 75 Garrett Turbine Engine Company Model

ATF3-6 and -6A turbofan engines of the affected design in the worldwide

fleet. The FAA estimates that 2 engines installed on aircraft of U.S.

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

220 work hours per engine to accomplish the required actions, and that

the average labor rate is $55 per work hour. Based on these figures,

the total cost impact of the AD on U.S. operators is estimated to be

$24,200.

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:

94-23-04 Garrett Turbine Engine Company: Amendment 39-9066. Docket

93-ANE-39.

Applicability: Garrett Turbine Engine Company Model ATF3-6 and -

6A turbofan engines equipped with high pressure turbine (HPT) rotor

assembly disk, Part Number (P/N) 3001765-1 and -2, listed by serial

numbers in Table 1 of Allied-Signal Aerospace Company, Garrett

Engine Division, Alert Service Bulletin (ASB) No. ATF3-A72-6184,

Revision 1, dated January 11, 1993. These engines are installed on

but not limited to Dassault Aviation Falcon Jet Falcon Series G

(Falcon 20G/HU-25) and Mystere-Falcon 200 aircraft.

Compliance: Required as indicated, unless accomplished

previously.

To prevent an uncontained failure of the HPT rotor assembly

disk, accomplish the following:

(a) For engines with 1550 or more HPT rotor assembly disk cycles

since new (CSN) on the effective date of this AD, perform a one-time

inspection for cracks of the curvic and bore area of the HPT rotor

assembly disk, and replace if necessary, with a serviceable disk, in

accordance with Allied-Signal Aerospace Company, Garrett Engine

Division, ASB No. ATF3-A72-6184, Revision 1, dated January 11, 1993,

within 50 cycles in service (CIS) after the effective date of this

AD.

(b) For engines with less than 1550 HPT rotor assembly disk CSN

on the effective date of this AD, perform a one-time inspection for

cracks of the curvic and bore area of the HPT rotor assembly disk,

and replace if necessary, with a serviceable disk, in accordance

with Allied-Signal Aerospace Company, Garrett Engine Division, ASB

No. ATF3-A72-6184, Revision 1, dated January 11, 1993, within 300

CIS after the effective date of this AD, or prior to accumulating

1600 CSN, whichever occurs first.

(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. The request should be forwarded through an appropriate FAA

Principal Maintenance Inspector, who may add comments and then send

it to the Manager, Los Angeles Aircraft Certification Office.

Note: Information concerning the existence of approved

alternative methods of compliance with this airworthiness directive,

if any, may be obtained from the Los Angeles Aircraft Certification

Office.

(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 aircraft to a location where

the requirements of this AD can be accomplished.

(e) The inspection, and replacement, if necessary, shall be done

in accordance with the following alert service bulletin:

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Document No. Pages Revision Date

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Allied-Signal Aerospace 1-6 1 Jan. 11, 1993.

Company, Garrett Engine

Division, ASB No. ATF3-A72-

6184.

Total Pages: 6.

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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 AlliedSignal Propulsion Engines,

Aviation Services Division, Data Distribution, Dept. 64-3/2102-1M,

P.O. Box 29003, Phoenix, AZ 85038-9003. Copies may be inspected at

the FAA, New England Region, Office of the Assistant Chief Counsel,

12 New England Executive Park, Burlington, MA; or at the Office of

the Federal Register, 800 North Capitol Street NW., suite 700,

Washington, DC.

(f) This amendment becomes effective on February 6, 1995.

Issued in Burlington, Massachusetts, on November 3, 1994.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification

Service.

[FR Doc. 94-28110 Filed 12-06-94; 8:45 am]

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