777 APU burn.
Joined: Feb 2000
Posts: 70
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From: Sand-Land
According to the MEL, the APU uses 240 KG/HR on the ground and 90 KG/HR in the air plus an additional 2.5% onto the trip fuel to account for the open APU air inlet door.
The QRH details this increment from 140 KG/HR at 43,000' and 140 Tons Gross weight to 270 KG/HR at 5,000' and 300 Tons Gross weight. The heavier the aircraft, and the lower the altitude, the higher the burn. The QRH values include the APU fuel flow and the effect of the increased drag from the APU door.
Hope that helps!
The QRH details this increment from 140 KG/HR at 43,000' and 140 Tons Gross weight to 270 KG/HR at 5,000' and 300 Tons Gross weight. The heavier the aircraft, and the lower the altitude, the higher the burn. The QRH values include the APU fuel flow and the effect of the increased drag from the APU door.
Hope that helps!
