AD 95-07-02

This amendment adopts a new airworthiness directive (AD), applicable to AlliedSignal Inc. (formerly Garrett Turbine Engine Company) TFE731-3 series turbofan engines, that requires the removal of suspect low pressure turbine (LPT) disks due to their susceptibility to creep fatigue. This amendment is prompted by reports of LPT disks that have separated through the disk web due to creep fatigue. The actions specified by this AD are intended to prevent an LPT disk web separation, which may result in an uncontained engine failure and damage to the aircraft.

Final rule.

95-07-02 AlliedSignal Inc.: Amendment 39-9181. Docket 94-ANE-42.
Applicability: AlliedSignal Inc. (formerly Garrett Turbine Engine Company) TFE731-3, -3A, -3AR, -3B, -3BR, and -3R turbofan engine models installed on but not limited to Avions Marcel Dassault Falcon 50, Lockheed 1329-23, -25 series (731 Jetstar, Jetstar II), Israel Aircraft Industries (IAI) Ltd. 1124 (Westwind), Raytheon Corporate Jets Inc. (formerly British Aerospace) (BAe) DH/HS/BH 125 series, Learjet 55 series, Cessna 650 Citation III, VI, Sabreliner NA-265 series (Sabreliner 65). This airworthiness directive (AD) is not applicable to TFE731-3A-300G and TFE731-3AR-200G engines installed on IAI 1125 Westwind Astra aircraft.
Compliance: Required as indicated, unless accomplished previously.
To prevent a low pressure turbine (LPT) disk web separation, which may result in an uncontained engine failure and damage to the aircraft, accomplish the following:
(a) Remove from service first and second stage LPTdisks, with Part Numbers (P/N) 3072351-( ), 3072542-( ), 3073113-( ), and 3073114-( ), where ( ) denotes any dash number, identified by serial number in the Compliance Sections of AlliedSignal Aerospace Alert Service Bulletin (ASB) No. TFE731-A72-3544, dated October 8, 1993, and AlliedSignal Aerospace ASB No. TFE731-A72-3557, dated May 12, 1994, within 1,500 hours time in service (TIS) after the effective date of this AD, or at the next removal of the LPT assembly, whichever occurs first, in accordance with the Accomplishment Instructions of AlliedSignal Aerospace ASB No. TFE731-A72-3544, dated October 8, 1993, and AlliedSignal Aerospace ASB No. TFE731-A72-3557, dated May 12, 1994, and replace with serviceable disks.
(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. 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.
(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 aircraft to a location where the requirements of this AD can be accomplished.
(d) The removal and replacement of the affected disks shall be done in accordance with the following AlliedSignal Aerospace ASB's:

Document No.
Pages
Date
ASB No. TFE731-A72-3544
1-10
October 8, 1993
Total Pages: 10.

ASB No. TFE731-A72-3557
1-12
May 12, 1994
Total Pages: 12.

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 Inc., Aviation Services Division, Data Distribution, Dept. 6403/2102-201, P.O. Box 29003, Phoenix, AZ 85038-9003; telephone (602) 365-2548, fax (602) 365-2210. 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.
(e) This amendment becomes effective on June 19, 1995.

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 AlliedSignal Inc. (formerly Garrett Turbine Engine Company) TFE731-3 series turbofan engines was published in the Federal Register on November 29, 1994 (59 FR 60922). That action proposed to require removal of suspect specific serial numbered first and second stage low pressure turbine (LPT) disks in accordance with AlliedSignal Aerospace Alert Service Bulletin (ASB) No. TFE731-A72-3544, dated October 8, 1993, and ASB No. TFE731-A72-3557, dated May 12, 1994.
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal. The Federal Aviation Administration's (FAA) has determined that the average labor rate has increased since publication of the NPRM to $60 per work hour. The economic analysis of this final rule has been changed accordingly. The FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will not increase the scope of the AD.
There are approximately 350 engines with the affected serial numbered disks in the worldwide fleet. The FAA estimates that 175 engines installed on aircraft of U.S. registry will be affected by this AD, that it will take approximately 10 work hours per engine to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $18,000 per engine. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $3,255,000.
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. 39.13 - [AMENDED]
2. Section 39.13 is amended by adding the following new airworthiness directive: