59-03-02 LOCKHEED: Applies to All Models 049, 149, 649, 649A, 749, 749A, and 1049-54 Aircraft Except Those Already Incorporating the Improved Main Landing Gear Downlock Guide Assembly Per Lockheed Service Bulletin 49/SB-707 and 1049/SB-2021.
Compliance required as indicated.
The following inspections and replacement have been established as a result of fatigue failures in the fillet radius of the main landing gear downlock guide stub, P/N 270201-3.
Unless already accomplished, within the next 150 flight hours inspect all Model 049, 149, 649, 649A, 749, 749A and 1049-54 aircraft for fatigue cracks in the main landing gear downlock guide stub fillet radius, P/N 270201-3, by magnetic inspection.
If cracks are found replace the entire main landing gear guide assembly, P/N 270197, with downlock guide assembly P/N 318332. If P/N 318332 is not available P/N 270201-3 may be replaced by an identical part pending final replacement of the guide assembly as indicated below.If no cracks are found the part must be reinspected in the same manner at intervals not to exceed 60 flight hours. This reinspection procedure may be terminated upon replacement by P/N 318332.
Unless sooner accomplished, P/N 270197 must be replaced by P/N 318332 at the first block overhaul after July 1, 1959, or in any case no later than July 1, 1960. (Lockheed Service Bulletins 49/SB-707 and 1049/SB-2021 describe the installation of P/N 318332.) (FAA telegraphic instructions of January 30, 1959, covered this subject.)