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QFE calculation from altitude


The_Dan

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I have seen some complains about the lack of QFE information in multiplayer, as there are no preprogrammed flight plans. As i have not seen a thread or post were it is explained how to get the QFE from the terrain elevation or any other altitude i decided to give a short "tutorial" :smartass:

The QFE can be calculated from the Barometric Formula. I think you don't need a derivation or crash curse in atmosphere physics so here is the formula to calculate the QFE for an target WP:

QFE.png.635a4f1ee788522d6127d90c125b50ec.png

P1 is the QFE for the target WP, P0 is the QFE for your starting point. At best, set and note on start up at the airfield. h1 is the target WPs elevation you can get it from the F10 map. h0 is your starting elevation, as P0 note the elevation of your starting airfield (use F10 map). T is the Temperature and is written down in the mission informations in the DCS briefing, just hit ESC and look at "Briefing" under "weather". T is in Degrees Celius, P0, P1 is just in hPa and h0, h1 is in meters.

Put this in a computer and the number it spits out is your needed QFE.

 

You can put this formula in an Excel or Calc table or in a fancy C#, java, whatever programm and get it calculated for every WP just as the information provided by the kneeboard. I've done a very simple example Calc file in the user files: https://www.digitalcombatsimulator.com/en/files/2708432/

 

Have fun :joystick:

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  • 2 years later...

Hey Dan thank you for that input and Happy new Year!

 

One small question couldn't we just also take p0=1013.25 HPa and eliminate h0, so we just have to enter the altitude of the target?

 

 

Edit: The difference in heights and using p0 as starting qfe seems to be more practical, but I just want to make sure I understood the formular correctly :D

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Here's the "Quick and Dirty" method.

 

 

QNH - ELEVATION = QFE

 

...It should however be obvious that what we must do instead is subtract the altitude of our destination (runway) while we ARRIVE, and before we APPROACH that airfield. If due to low cloud we were forced to cruise at (say) 1000M QNH and our destination runway is at 230M QNH, then BEFORE we enter the circuit pattern for that runway we must wind the altimeter down by 230M until it displays 770M QFE, so that it will read (about) ZERO QFE as we land, and will read exactly 250M QFE downwind in the circuit pattern at every destination,
"A.V.I.A. L.3 Student Training Manual," available in the FS2004 AVIA L3 Open Cockpit MVG freeware aircraft. It can be downloaded from various flight simulator sites as "l3_v01-open_cockpit.zip"
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