What is the minimum fuel for ground operation of electric motor-driven pumps in the related main tank?

• A. 1675 lbs
• B. 1700 lbs
• C. 1800 lbs
• D. 1600 lbs

Answer: (A)

The key idea is that the fuel in the related main tank must be enough to keep the electric motor-driven pumps primed and able to operate during ground tasks without drawing air or losing pressure. If fuel quantity is too low, the pumps can cavitate, lose prime, or fail to deliver the required flow for testing, fuel transfer, or other ground operations, which could compromise the system work and safety.

1675 pounds is the value chosen because it provides the necessary fuel head and a reserve to cover the pump’s operation duration on the ground, given the tank geometry and suction location. That level ensures reliable pump operation without overstraining the system or wasting more fuel than needed. The other amounts don’t guarantee adequate priming and flow, or they would unnecessarily reduce available mission fuel.