If the left boost pump is off and crossfeed is on, which system supplies fuel to both engines?

If the left boost pump is off and crossfeed is on, which system supplies fuel to both engines?

• A. Both engines will receive fuel from the left system
• B. Both engines will receive fuel from the right system
• C. Each engine continues to be fed from its own respective system
• D. Fuel supply to both engines stops

Answer: (B)

When you have two independent fuel systems with a crossfeed, each engine normally gets fuel from its own side. The crossfeed valve lets you connect the two sides so you can feed an engine from the opposite side if its own supply is unavailable. If the left boost pump is off, there’s no active left-side source to feed the left engine. With the crossfeed on, fuel from the right-side system is routed through the crossfeed to the left engine. The right engine stays fed by its own right-side system. So the right system becomes the source for both engines.

When you have two independent fuel systems with a crossfeed, each engine normally gets fuel from its own side. The crossfeed valve lets you connect the two sides so you can feed an engine from the opposite side if its own supply is unavailable.

If the left boost pump is off, there’s no active left-side source to feed the left engine. With the crossfeed on, fuel from the right-side system is routed through the crossfeed to the left engine. The right engine stays fed by its own right-side system. So the right system becomes the source for both engines.