82-23-03 R1: High Pressure Compressor Impellers

82-23-03 R1 GARRETT TURBINE ENGINE COMPANY: Amendment 39-4488 as amended by Amendment 39-4761. Applies to all Garrett TFE731-2, -3, -3R, -3A, -3AR, -3B and -3BR series turbofan engines. Compliance required as indicated unless already accomplished. (a) To prevent failure of high pressure compressor impellers due to cracks originating from a double radius in the seal relief region or a manufacturing notch in the forward balance ring, inspect and rework compressor impeller, Part Number 3070274-1 or 3072639-1, in accordance with the procedures contained in the accomplishment instructions section of Garrett Service Bulletin Number TFE731-72-3239RWK, dated September 13, 1982, or equivalent means approved by the Manager, Western Aircraft Certification Field Office, ANM- 170W, Northwest Mountain Aircraft Certification Division. Inspect in accordance with the following schedule: (1) Impellers which have been operated in TFE731-3, -3R, -3A, -3AR, -3B, or -3BR engines during any portion of their service lives must be inspected prior to exceeding 5,100 cycles in service. NOTE: The engine life limited parts log card for each impeller is located with the impeller or in the engine log book. This card lists the engine serial number of each engine in which the impeller has operated. The 5 digit serial numbers of the TFE731-3 series engines begin with the 2 digits 75, 76, 77, 78, 80, 82, 83, 84, 85, 87, 90, or 94. (2) Impellers which have been operated in TFE731-2 engines, only, must be inspected prior to exceeding 6,200 cycles in service. NOTE: The 5 digit serial numbers of the TFE731-2 series engines begin with the 2 digits 73, 74, 81, 86, 88, or 89. Impellers found to have crack indications are to be removed from, and not returned to, service. Impellers not found to have crack indications may be returned to service after having the seal relief region and notch in the forward balance ring recontoured in accordance with the procedures contained in the accomplishment instructions section of Garrett Service Bulletin Number TFE731-72-3239 RWK, dated September 13, 1982, or equivalent means approved by the Manager, Western Aircraft Certification Field Office, ANM-170W, Northwest Mountain Aircraft Certification Division. (b) To prevent cracking and possible failure of the following listed fan and compressor rotor discs, used in TFE 731-2 series engines, the life limits on these parts have been reduced. Unless already accomplished, remove rotor discs from service prior to reaching the life limits shown below or, before accumulation of an additional 30 cycles in service after March 7, 1975, whichever occurs later: Component Part Number Life Limit in Cycles Fan Disc 3072162 10,000 First Stage Compressor 3072190 3,000 Second Stage Compressor 3072191 3,700 Third Stage Compressor 3072192 1,200 Fourth Stage Compressor 3072193 1,200 NOTE: For the purpose of this AD, a cycle is considered as any engine operating sequence involving an engine start, at least one acceleration to 80 percent low pressure rotor speed or above, and shutdown. NOTE: Garrett FAA approved Service Bulletin TFE731-72-3001, Revision 15, dated June 30, 1983, provides the cyclic life limits for all life limited components not covered by this AD. This bulletin may be revised in the future, with the approval of the FAA, in order to provide life limit increases if appropriate. (c) Service life limits have been assigned to the following specific parts used in the TFE731-2 series engines: (1) Replace the High Pressure Turbine Blades, Part Number 3072111-1, (used in high pressure turbine rotor assembly, part number 3070098), with serviceable turbine blades before exceeding 1,000 hours total time in service, or before exceeding 200 additional hours time in service after March 7, 1975, whichever occurs later. (2) Model TFE731-2 engines Serial Numbers P-74101 through P-74113 and Serial Numbers P- 73106 through P-73184 not modified by incorporation of Power Section Change Number 22: Replace the Pinion Gear Assembly, Part Number 3071626-1, and Sun Gear, Part Number 3071598-1, with a serviceable Pinion Gear Assembly and Sun Gear before exceeding 500 hours total time in service, or before exceeding an additional 50 hours time in service after March 7, 1975, whichever occurs later. (3) Model TFE731-2 engines Serial Numbers P-74101 through P-74138 and Serial Numbers P- 73106 through P-73209 not modified by incorporation of Power Section Change Number 41 or 44: Replace the Third Stage Compressor Stator Assembly, Part Number 3070279-7, -8, or -10, with a serviceable Third Stage Compressor Stator Assembly before exceeding 500 hours total time in service, or before exceeding an additional 50 hours time in service after March 7, 1975, whichever occurs later. NOTE: Power Section Change Numbers are annotated on the Engine Data Plate affixed to the engine. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Garrett Turbine Engine Company, P.O. Box 5217, Phoenix, Arizona 85010. These documents also may be examined at FAA New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, Massachusetts. This Amendment 39-4761 amends Amendment 39-4488 (47 FR 50462), AD 82-23-03, and supersedes Amendment 39-2116 (40 FR 8939), AD 75-05-12. Amendment 39-4488 became effective November 15, 1982. This Amendment 39-4761 becomes effective December 9, 1983.