How much unusable fuel is on board in US gallons?

How much unusable fuel is on board in US gallons?

• A. 0.5 US GAL
• B. 0.0 US GAL
• C. 0.25 US GAL
• D. 1.0 US GAL

Answer: (A)

Unusable fuel is the portion of fuel that cannot be pumped to the engine because of the fuel system design and tank geometry. In the DA20-C1, this amount is 0.5 US gallons. That means even though you may see a certain total on the gauge, only the usable fuel can be counted for flight planning—the 0.5 gallons stays in the tanks/lines and isn’t deliverable to the engine. The other figures don’t fit because in this aircraft there is always some residual fuel due to the way the fuel pickup and lines are arranged; 0.0 would ignore that reality, 0.25 would imply a smaller residual, and 1.0 would exceed what the system leaves behind.

Unusable fuel is the portion of fuel that cannot be pumped to the engine because of the fuel system design and tank geometry. In the DA20-C1, this amount is 0.5 US gallons. That means even though you may see a certain total on the gauge, only the usable fuel can be counted for flight planning—the 0.5 gallons stays in the tanks/lines and isn’t deliverable to the engine. The other figures don’t fit because in this aircraft there is always some residual fuel due to the way the fuel pickup and lines are arranged; 0.0 would ignore that reality, 0.25 would imply a smaller residual, and 1.0 would exceed what the system leaves behind.