Originally Posted by
PompeyPaul
I understand the differences between QFE & QNH. I don't understand how you map one to the other though, i.e.
Your aerodrome elevation is 24 ft, and the QFE you have just been given is 1021 millibars. What would you expect the aerodrome QNH to be?
A 1015 millibars
B 1020 millibars
C 1022 millibars
D 1027 millibars
Obviously I need to work out the pressure difference 24ft makes and add it to 1021 to get the result. Is there some constant mapping per foot of pressure ? Anyone ?
Thanks
So in this instance the answer is C.. 1022. As has been said, pressure drops with altitude gained. Given that 1mb = 30ft, QFE at MSL (and hebce QNH) would be 1022, (24ft lower giving an increase of approx 1mb).
I'm pretty sure that's right!
.. I hope. It is past my bed time!
Well done on the exam pass!!