AD 59-26-07

59-26-07 LOCKHEED: Amdt. 73 Part 507 Federal Register December 19, 1959. Applies to Models 649 and 749 Aircraft, Serial Numbers 2518 Through 2524, 2529 Through 2535, 2548, 2549, 2554 Through 2556, 2610, 2611, 2614 Through 2618, 2642, 2653, 2659, 2660, 2662 Through 2673, Model 1049-54 Serial Numbers 4001 Through 4024 and Model 1049C, Serial Numbers 4523 Through 4538.

Compliance required as indicated.

As a result of cracks discovered in forward passenger door latch brackets the following shall be accomplished on the above serial numbered aircraft which have accumulated flight time of 10,000 hours or more.

Unless already accomplished, within the next 200 hours of service time and at each succeeding 1,000 hours of service time the following inspections are required:

(a) Models 649 and 749 aircraft.

(1) Remove and inspect by the dye penetrant method the top and bottom P/N 291924-2 and -3 brackets of the P/N 291941-2 and -3 top and bottom latch assemblies of the P/N 290809 forward passenger door assembly for cracks in the fillet radius of attach flanges of the brackets.

(Lockheed Field Service Letters FS/222746 and FS/220393-W pertain to this subject.)

Cracked latch brackets must be replaced. The replacement part may be either a new bracket of the same part number, the improved latch assembly P/N 554278-1, P/N 554389-1 or P/N 554289-3, whichever is applicable, or an equivalent item.

(2) Check door rigging and condition of safety bar and hooks.

(b) Models 1049-54 and 1049C aircraft.

(1) Remove and inspect by the dye penetrant method the upper lower aft P/N 291925 and/or P/N 308236 brackets of the P/N 291940 and P/N 338239 upper and lower aft latch assemblies of the P/N 308269 and P/N 308269-600 forward passenger door assemblies for cracks in the fillet radius of the attach flanges of the brackets.

(Lockheed Field Service Letters FS/222746 and FS/220393-W pertain to this subject.)

Cracked latch brackets must be replaced.The replacement part may be either a new bracket of the same part number, the improved latch assembly P/N 554278-3, P/N 554289-1, or P/N 554289-3, whichever is applicable, or an equivalent item.

(2) Check door rigging and condition of safety bar and hooks.

When the improved latch assemblies (identified above by part number) are installed, this inspection procedure may be terminated. When the replacement bracket is identical to the originally installed bracket, this inspection procedure is to be reestablished upon accumulation of 10,000 flight-hours on the replacement brackets.

(Lockheed Service Bulletins 49/SB-882 and 1049/SB-3052 describe the installation of the improved latch assemblies mentioned above.)