If the L FUEL PRESS LO annunciator illuminates, the correct crew action is:

If the L FUEL PRESS LO annunciator illuminates, the correct crew action is:

• A. Left boost pump ON, Left jet pump OFF
• B. Right boost pump ON, Right jet pump OFF
• C. Both pumps ON
• D. Left boost pump OFF, Left jet pump ON

Answer: (A)

When L FUEL PRESS LO lights, the left fuel pressure has fallen below acceptable levels. The immediate goal is to restore pressure to the left engine using a reliable source, and to isolate a potentially faulty left jet pump. Turn on the left boost pump. This electric pump will boost fuel pressure in the left system, helping maintain engine fuel flow even if the primary left jet pump isn’t delivering adequate pressure. At the same time, switch off the left jet pump to isolate the suspected failed pump and prevent it from pulling fuel or creating pressure instability that could complicate the situation. Using the left boost pump alone provides a stable, higher-pressure supply to the left engine, which is the primary objective in this scenario. The other options don’t address the left-side low pressure properly: turning on the right boost pump won’t fix the left system, turning on both pumps could mask or delay recognizing a left-side pump fault, and leaving the left jet pump on but not reinforcing with the boost pump won’t resolve the low pressure.

When L FUEL PRESS LO lights, the left fuel pressure has fallen below acceptable levels. The immediate goal is to restore pressure to the left engine using a reliable source, and to isolate a potentially faulty left jet pump.

Turn on the left boost pump. This electric pump will boost fuel pressure in the left system, helping maintain engine fuel flow even if the primary left jet pump isn’t delivering adequate pressure. At the same time, switch off the left jet pump to isolate the suspected failed pump and prevent it from pulling fuel or creating pressure instability that could complicate the situation.

Using the left boost pump alone provides a stable, higher-pressure supply to the left engine, which is the primary objective in this scenario. The other options don’t address the left-side low pressure properly: turning on the right boost pump won’t fix the left system, turning on both pumps could mask or delay recognizing a left-side pump fault, and leaving the left jet pump on but not reinforcing with the boost pump won’t resolve the low pressure.