65-24-02\tBOEING: Amdt. 39-146 Part 39 Federal Register September 30, 1965. Applies to Models 707 and 720 Series Airplanes. \n\n\tCompliance required within the next 1,800 hours' time in service after the effective date of this AD unless already accomplished.\n \n\tTo prevent further false indications of thrust reverser operation as a result of malfunction of the thrust reverser indicating light switch and switch wiring, accomplish the following: \n\n\t(a)\tOn airplanes equipped with JT3D turbofan engines, modify as follows: \n\n\t\t(1)\tOn airplanes modified in accordance with Boeing Service Bulletin No. 1896, dated November 1963, replace each aft thrust reverser indicating light switch with sealed switch, P/N 2HT13, in accordance with Boeing Service Bulletin No. 1896, or an equivalent. \n\n\t\t(2)\tOn airplanes not modified in accordance with Boeing Service Bulletin No. 1896, replace each aft thrust reverser indicating light switch with sealed switch, P/N 2HT13, in accordance with Boeing Service Bulletin No. 1884, dated January 1964, or an equivalent. \n\n\t\t(3)\tInterchange the electrical leads on the forward and aft thrust reverser indicating light switches in accordance with Boeing Service Bulletin No. 2170, dated May 1965, or an equivalent. \n\n\t(b)\tOn airplanes equipped with JT3C or JT4A turbojet engines, modify the thrust reverser indicating light switch wiring by interchanging the electrical leads in accordance with Boeing Service Bulletin No. 2170 or an equivalent. \n\n\t(c)\tApproval of any equivalent shall be processed through the Aircraft Engineering Division, FAA Western Region. \n\n\tThis directive effective October 29, 1965.