47-49-11 LOCKHEED: (Was Service Note 11 of AD-763-3.) Applies to Models 49, 649, and 749 Serials as Noted.
At periods not to exceed 50 hours of operation, inspect the following fuel system elements to determine that they are tight and will not permit leakage or other hazardous conditions:
(a) Fuel dump valve shaft gland nuts (Serials up to and including 2075).
(b) Valves on drain lines from outboard portion of inboard fuel tanks, fuel system crossfeed lines, and cabin heater fuel lines (Serials 2047 to 2088, inclusive, and 2501 to 2503, inclusive).
If safety wiring of these items is provided, the required inspections may be discontinued.
(Lockheed Service Bulletin 49/SB-215 covers part (a), and Lockheed Service Instruction 49/SI-10A covers part (b).)