80-09-11\tTELEDYNE CONTINENTAL MOTORS: Amendment 39-3763. Applies to Model GTSIO-520 series engines overhauled by AAR Western Skyways, Inc. \n\tTo prevent the possible separation of the starter torsional damper from the starter gear shaft and subsequent damage to critical components in the engine nacelle, accomplish the following: \n\ta.\tPrior to next flight: \n\t\t1.\tRemove engine cowling to the extent that the rear of the engine, where the starter and/or starter adapter are installed, can be seen. \n\t\t2.\tInspect the locking device at the outboard end of the starter gear shaft, which secures the torsional damper (see Figure I) for proper installation of all required parts. There must be a snap ring (TCM P/N 502171), a nut lock key (TCM P/N 632980), a compression spring (TCM P/N 628311) and a Marsden slotted hex nut (TCM P/N 632979) installed. \n\t\t3.\tIf all of the parts (in 2. above) are installed correctly, no further action is required. \n\tb.\tIf all the parts (in a.2. above) are not installed or are of the incorrect part, accomplish the following: \n\t\t1.\tPrior to the next flight and within every 25 hours engine operating time thereafter until all correct parts are installed, check the torque on the existing hexagon nut on the starter gear shaft to 180-220 foot pounds. For installations incorporating a compressor sheave for air conditioner drive, the hex nut must be checked for a torque of 195-235 foot pounds. \n\t\t2.\tWithin 100 hours engine operating time after the effective date of this AD, install all correct parts in accordance with TCM overhaul manual instructions. \n\tParts may be obtained from Teledyne Continental Motors, P.O. Box 90, Mobile, Alabama 36601, telephone (A/C 205) 438-3411, or AAR Western Skyways, Inc., Troutdale, Oregon, telephone (A/C 503) 665- 1181 or any other Teledyne Continental Motors distributor. \n\n\t\nc.\tAircraft may be flown in accordance with FAR 21.197 to a base where the repairs required by this AD can be accomplished. \n\tAn equivalentmethod of compliance may be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region, P.O. Box 20636, Atlanta, Georgia 30320. \n\tThis amendment is effective upon publication in the Federal Register as to all persons except those persons to whom it was made immediately effective by priority mail, issued April 3, 1980, which contained this amendment.