56-04-02: Fuel Supply Lines

56-04-02 CONVAIR: Applies to All 240 and 340 Aircraft. Compliance required as soon as possible but not later than February 1, 1957, for Model 240 and August 1, 1957, for Model 340. As a result of a recent accident involving a nacelle fire, additional fire protection for the nacelle is required. The following changes or equivalent must be made to accomplish the above: 1. Replace aluminum alloy engine fuel supply lines, and sleeves, nuts and tube unions, with steel lines in the wheel well area (zone 3), except for lines and fittings outboard of the main landing gear beam. This does not apply to lines and fittings between cross-feed valves. 2. Replace present flexible hose assemblies in the engine fuel supply system in the wheel well area (zone 3), including AN fittings, with steel tubing and/or fireproof flexible lines, except for lines and fittings outboard of the main landing gear beam. Flexible lines qualifying as fireproof may incorporate either steel or aluminum fittings. 3. (a) CV-340 airplanes only. Replace aluminum alloy propeller pump suction line in left-hand nacelle wheel well (zone 3) with a steel line. (b) CV-240 airplanes only. Replace aluminum alloy propeller pump suction line in wheel well area (zone 3) with a steel line. (Both nacelles.) (Original flexible hose connections will be satisfactory if provided with a steel liner.) 4. Protect existing oil hose assemblies in wheel well area (zone 3) with asbestos sleeves or equivalent. 5. Replace all micarta pulleys in wheel well area (zone 3) with aluminum alloy pulleys. (Convair Service Bulletins Numbers 240-467 and 340-167 cover items 1 through 4. Convair Service Bulletins Numbers 240-468 and 340-166 cover item 5. These bulletins also contain some items which are not mandatory but are recommended.