Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-400, -400D, -400F; 767-200, -300, -300F; and 777-200 and -300 series airplanes. This proposed AD would require installing a jumper wire between the wiring of the fire extinguisher switch and the fuel shutoff switch for each engine, and other specified actions. This proposed AD is prompted by a certain combination of conditions, which could cause the fuel spar shutoff valves to remain partially open. We are proposing this AD to prevent a latent open circuit that could leave the fuel spar shutoff valve in a partially open position when the engine fire switch is activated, which could result in fuel from the engine feeding an uncontrolled fire in the engine or the strut.