94-23-04: High Pressure Turbine Rotor Assembly Disks

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: Document No. Pages Revision Date Allied-Signal Aerospace Company, Garrett Engine Division, ASB No. ATF3-A72-6184 1-6 1 January 11, 1993 Total Pages: 6. 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.