61-24-03 DOUGLAS: Amdt. 371 Part 507 Federal Register November 23, 1961. Applies to All DC-8 Aircraft, Serial Nos. 45252-45289, 45291-45306, 45376-45393, 45408-45413, 45416-45419, 45421-45431, 45433-45437, 45442-45445, 45526, 45565-45570, 45588-45606, 45609-45614, 45616-45628, 45636. \n\n\tCompliance required within 1,000 hours' time in service after the effective date of this AD, but in no event later than February 28, 1962. \n\n\tTo prevent inadvertent application of forward thrust when reverse thrust is desired under emergency conditions, the following modification shall be accomplished: \n\n\tIncorporate a throttle-thrust brake interlock system which will: \n\n\t(a)\tPrevent application of reverse thrust until the reverse buckets are in the reverse thrust position, and \n\n\t(b)\tReturn a throttle to the detent position should the corresponding buckets move from the reverse thrust position. \n\n\tThe modification shall be accomplished in accordance with technical data approved by theChief, Engineering and Manufacturing Branch, FAA Western Region. \n\n\t(Douglas DC-8 Service Bulletin Nos. 78-48, 78-50, 78-51 and 78-52 for DC-8 aircraft equipped with JT3C6, JT3D-1, JT4A and Rolls Royce RCO-12 engines, respectively, pertain to this same subject and describe particular FAA approved means of compliance with this AD.) \n\n\tWhen the above modification is accomplished, compliance with the provisions of AD 61-21-02 is no longer required. \n\n\tThis directive effective November 23, 1961.