65-17-01\tBOEING: Amdt. 39-108 Part 39 Federal Register July 24, 1965. Applies to Model 727 Series Airplanes. \n\n\tCompliance required within the next 600 hours' time in service after the effective date of this AD unless already accomplished. \n\n\tTo prevent inadvertent thrust reversing from failure to the locking pin, replace the thrust reverser lockout actuator piston, P/N 65-37853-2, on each engine, with actuator piston, P/N 65- 37853-3, in accordance with Boeing Alert Service Bulletin No. 78-18, or later FAA-approved revision, or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\tThis directive effective August 23, 1965.