Fuel evaporation

[fuelevaporator]

Fuel temperature before flight here sometimes 45 degrees centigrade. How much of the fuel will disappear through the vents before the fuel temperature is down to "normal level" at high altitude?
Am making some statistics by adding fuel on board and fuel used after APU shut down and then during flight.
Many times this total drops by more than half of route reserve during cruise.
Sometimes back on ground half losses recover but sometimes not.
Have never seen this total going up as would be normal behavior when arguing with "tolerance".
:confused:

[kijangnim]

Greetings
I may be wrong but at that temperature you could be above temperature limitation to operate Hydraulic pumps, thus not legal to fly the aircraft in such conditions.:}

[Piper19]

I've tried to read this question several times and I want to help you with it, but I really cannot make up what you ask.
Our manual only says the hydraulic heat exchangers in the fuel tank need to be covered by a certain amount of fuel on ground ops. Nothing said about fuel temp, but I guess it plays a role. Altough we operated many times in temperatures above 50°C, I didn't see fuel quantity changes.

[kijangnim]

Greetings,
PIPER 19, which type of aircraft are you flying?

[VinRouge]

Not a problem with AVTUR.

Herc has correction factors when aircraft is used with AVGAS; its significant. I think something like 20% of the fuel is assumed to 'boil off' at high ambient temps and final cruise around FL290.