75-22-13 LITTON SYSTEMS, INC., AERO PRODUCTS DIVISION: Amendment 39-2404. Applies to all LTN-72 inertial navigation systems installed on various airplane models, certificated in all categories, including, but not limited to, McDonnell Douglas DC-8 and DC-10 airplanes and Boeing 707 and 747 airplanes. \n\n\tCompliance required as indicated prior to January 1, 1976 unless already accomplished. \n\n\tTo provide the required failure warning indication of power loss, accomplish Litton Service Bulletin No. 34-72-80, dated February 20, 1975, or later FAA-approved revision, or an equivalent installation approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\tThis amendment becomes effective December 1, 1975.