Fuel hose couplings

Aviation Boatswains Mate F - Aviation theories and other practices
Page Navigation
155

only and require installation of the couplings and continuity wire. One end has a male coupling and the other end has a swivel-type female coupling (fig. 5-13). Leakage between the couplings is prevented by an O-ring in the female coupling. Both couplings are machined to receive the nylon spiders that act as non-conducting supports for connecting the continuity wire. The con- tinuity wire runs through the hose and is slightly longer than the hose, to allow for hose stretching. New hoses and hoses that were out of service for a long time must be cured (pickled) before being placed in service. Use the following procedure: NOTE Some new hoses manufactured according to Mil-H-17902 do not require pickling. How-ever, they must still be flushed and tested prior to use. 1. Flush the hose with 100 gallons of fuel. 2. Cap one end and elevate the hose. 3. Fill the hose, cap it and let it stand for at least 1 week. 4. Drain the hose and observe drainage for discoloration. (If discoloration is observed, repeat steps 1 through 3. 5. Test the fuel with the CFD. (Should be less than 10 mg/1.) 6. Install the hose and flush until acceptable fuel is sampled. (Less than 2 mg/1.) Because of their environment, fuel hoses are sub- jected to severe wear and tear. They should be in- spected during each use for superficial cuts, worn areas or bubbles in the hose, deep cuts that expose the wire reinforcement or inner layer wrapping, and leaky couplings. If any of the above is observed, notify the flight deck supervisor, flight deck control, and flight deck repair immediately. You can prolong the useful life of fuel hoses by not twisting or kinking a hose, not rolling a twisted or kinked hose up on its reel, and not allowing aircraft, tractors. or other rolling stock to run over the hoses. New fuel hoses are hydrostatically tested before being placed in-service, and in-service hoses are hydrostatically tested annually. In accordance with PMS requirements, fuel hoses are tested at 1 1/2 times their system operating pressure. If a hose is found to be damaged near an end coupling but otherwise usable, it may be salvaged by cutting the damaged area off. This is known as “cut- ting back” a hose. To cut back a fuel hose, do the following: 1. Disconnect and remove the spiders and conti- nuity wire from the hose. 2. Remove the coupling from the damaged end. a. Unscrew the external taper sleeve from the coupling end and slide it down past the damaged area. Figure 5-13.—Fuel hose couplings. 5-12

Privacy Statement
Press Release
Contact