FPH

Hi there - I'm doing some work on extracting atmospheric information
from the flight log of a well-instrumented glider, but there is one
measurement that is baffling me - what is FPH a measure of?

It is measured in degrees and ranges between 0 and 180 degrees over
the whole flight. I initially thought it might have been a heading of
some sort, but the range seeems to disagree with that.

Any info would be appreciated.

thanks,
Richard