When does the spar fuel shutoff valve open?

When does the spar fuel shutoff valve open?

• A. Start lever moved to IDLE
• B. Start lever moved to OFF
• C. EEC signal to open
• D. N2 exceeds 60%

Answer: (A)

The spar fuel shutoff valve opens when the start lever is moved to IDLE. This position starts the fuel flow path to the spar system, allowing fuel to reach the combustor for light-off and spin-up of the APU. If the start lever is OFF, fuel is not allowed through, so the valve stays closed. The other options don’t control this opening in the same way. An EEC signal to open isn’t the commanded source for this valve in this context, and waiting for N2 to exceed a threshold (like 60%) is just a speed condition, not the start control for the spar valve. Moving the lever to IDLE is the intentional cue to begin fuel flow for starting.

The spar fuel shutoff valve opens when the start lever is moved to IDLE. This position starts the fuel flow path to the spar system, allowing fuel to reach the combustor for light-off and spin-up of the APU. If the start lever is OFF, fuel is not allowed through, so the valve stays closed.

The other options don’t control this opening in the same way. An EEC signal to open isn’t the commanded source for this valve in this context, and waiting for N2 to exceed a threshold (like 60%) is just a speed condition, not the start control for the spar valve. Moving the lever to IDLE is the intentional cue to begin fuel flow for starting.