AD 75-10-05

75-10-05 AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Amendment 39-2198 as amended by Amendment 39-2255. Applies to certain Models and serial numbers of TPE331 series engines as follows:

Model Serial Number Effectivity TPE331-1-101B P-93058 through P-93064 TPE331-1-151A P-92249, P-92336 through P-92356 TPE331-1-151K P-91194, P-91195, P-26001 through P-26022 TPE331-1-151G P-91193, P-91196 through P-91198 TPE331-2-201A P-90281 through P-90294, P-90296 TPE331-3U/3UW-303G P-03108, P-03109, P-03112 through P-03193, P-03195, P-05031 through P-05048 TPE331-3U-307G/-303G P-03001, P-03009 TPE331-5-251C P-22006 through P-22103 TPE331-5-251K P-06113, P-06190 through P-06442, P-06444 through P-06537 TPE331-6-251M/-252M P-20144, P-20182 through P-20577 TPE331-6-252B P-27001, P-27002

In addition to the above serial number engines, also affected by this AD are any Model TPE331-1, -2, -3, -5, or -6 series engines which have been modifiedin accordance with AiResearch Service Bulletin TPE331-72- 0064, dated February 1, 1974 or subsequent FAA-approved revision.

Compliance required as indicated.

To detect, correct and prevent loosening of the torque sensor assembly mounting arm, accomplish the following:

(a) Engines with less than 200 hours total time in service since new or last overhaul: Before exceeding 200 hours total time in service, or an additional 25 hours time in service after the effective date of this AD, whichever occurs later, inspect the fuel control assembly drive in accordance with the instructions contained in paragraph 2.C. of AiResearch Service Bulletin TPE331-72-0095, dated April 18, 1975, or later FAA-approved revision. If the fuel pump and control drive backlash exceed the limits specified in the above referenced service bulletin, modify the torque sensor assembly mounting arm per the instructions contained in paragraph 2.D. of that bulletin before further flight.

(b) Engines with more than 200 hours total time in service since new or last overhaul: Before exceeding an additional 100 hours time in service after the effective date of this AD, inspect fuel control assembly drive, and modify the torque sensor assembly mounting arm per paragraph (a), above, as necessary.

(c) If the fuel control assembly drive meets the backlash limits specified in the above referenced service bulletin, the inspections required in paragraphs (a), and (b), above, must be repeated at intervals not to exceed 400 hours thereafter until the torque sensor assembly mounting arm is modified per paragraph 2.D of the above referenced service bulletin. This modification must be incorporated before the affected engine exceeds the time in service since new or overhaul at the manufacturer's recommended mid-term inspection as defined in paragraphs 2.A., 2.C., or 2.D. of the Revision No. 7, dated March 20, 1975, or later revisions, of AiResearch Service Bulletin No. 606; or, if this mid-term inspection has already been accomplished prior to the effective date of this AD, before exceeding the recommended overhaul period as defined in the Service Bulletin No. 606, Revision 7, dated March 20, 1975, as revised.

NOTE: Engine Models TPE331-6-252B and -252M are not specifically included in the above referenced Service Bulletin No. 606. Refer to paragraph 2.D of this service bulletin for mid-term inspection and overhaul times applicable to these engine models.

(d) Equivalent procedures may be approved by the Chief, Aircraft Engineering Division, FAA Western Region, upon submission of adequate substantiation data.

(e) Aircraft may be flown to a base for performance of inspections as required by paragraphs (a) and (b) above per FAR's 21.197 and 21.199.

Amendment 39-2198 became effective May 15, 1975. This amendment 39-2255 becomes effective July 11, 1975.