78-25-08 R3 AIRESEARCH MANUFACTURING COMPANY OF ARIZONA: Amendment 39-3367 as amended by Amendment 39-3389 and 39-3607 is further amended by Amendment 39-3787. Applies to AiResearch Model TSE331-3 and TPE331-1, -2, -3, -5, -6 series engines.
Compliance required as indicated.
To prevent destructive overspeed of the turbine rotor in the event of any one of several single engine failures in the main reduction gear drive accomplish the following:
(a) Within the next 3100 hours' time in service after July 1, 1979, or at the next overhaul after July 1, 1979, or prior to December 31, 1985, whichever comes first, unless already accomplished, incorporate the modified engine fuel control drive gear train in the main reduction gear box of the TSE331-3U and TPE331-1, -2, -3U, -3UW, -5, and -6 series engines in accordance with AiResearch Service Bulletin TPE331-72-0061, revision 1, dated December 18, 1978 or revision 2 dated October 18, 1979. Torque sensor assembly P/N 3101726-2 may be used in place of P/N 3101726-1. Installation of torque sensor assembly P/N 3101726-2 is per paragraph 2.E of AiResearch Service Bulletin TPE331-72-0232, Revision 1, dated December 5, 1979.
(b) Equivalent procedures may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region.
(c) Special flight permits may be issued per FAR 21.197 and 21.199 to authorize operation of aircraft to a base where this modification required by this AD may be performed.
Amendment 39-3367 became effective January 19, 1979.
Amendment 39-3389 became effective January 8, 1979.
Amendment 39-3607 became effective November 19, 1979.
This Amendment 39-3787 becomes effective June 12, 1980.