If operating above 8000 ft MSL, both boost pumps shall be on to prevent a possible feed tank failure. At what altitude should this be done?

• A. 6000 ft
• B. 8000 ft
• C. 10000 ft
• D. 12000 ft

Answer: (B)

The main idea is ensuring a reliable fuel feed to the engine, which becomes more vulnerable as you climb. The boost pumps actively push fuel from the tanks into the engine fuel system, and at higher altitudes the surrounding air is thinner, making it easier for the feed to lose pressure or for the engine to ingest air if only one pump is working. Energizing both boost pumps at 8,000 feet MSL and above provides redundancy and sufficient flow to the engine, reducing the risk of feed tank starvation or failure. Below that altitude, a single pump generally provides adequate pressure, so using both pumps is not required unless conditions demand it.