Originally Posted by
rickair7777
There are different vedrsions of jet A for that sort of flying, I assume you use one. Standard domestic Jet A is supposed to gell at -40C.
Hi Rick
We use standard Jet A. I agree that the minimum specification fuel freeze (gel) point is -40 C. However most fuel actually exceeds the specification, and freezes at a lower temperature. Prior to each polar flight a sample of the actual fuel boarded is taken to a lab, and the actual freeze (gel) temperature is determined. We then use the actual fuel freeze temp plus 3 degrees C as our in flight fuel temp limit. If fuel temp approaches the limit, it may be necessary to change to a warmer altitude or increase Mach to get a warmer temp.
Joe