QFE/QNH Conversion
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Joined: Aug 2000
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From: Zurich
QFE/QNH Conversion
Okay, I've done this before but how did it go again? You're inbound Moscow and you're given the local QFE and want to convert it to QNH.So do I take the Altitude difference divided by 27 feet and add it to the QFE or what?I know you might be given the local QNH, however I'd like to know how it could be done.Thanks
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Yup, take the ad elevation in feet div by 30 (or 27 if you prefer) and that gives you a number to add to the QFE in hPa to give a pretty good approximation of the QNH. Look out for different units of measurements - obvious but important!
Joined: Mar 2003
Posts: 341
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From: deco stop
almost all the answer-
The 27ft per Hpa, or 30 ft is a perfect answer.
Take the published airport elevation, and divide by 30. This gives a very close Hps to be added to the QFE. The Russian system normally provides a QFE. This gives the QNH.
There are several discussions that suggest working in GFE or in QNH when working in Ruiisa.
Most FMS display the runway evelvation, if feet; so will show 690ft for example on 24 at VNO.
Many operators deduct 690 ft, or use the Jepp published plate QFE value, and input in the FMS, for all values below the Transition, either 1500mt or 1800mt.
I would strongly recomend creation of a laminated data sheet, to fit on the control wheel chart data sheet, with BIG numbers.
This data sheet showing the relevent FL in feet to FL in meters. and show 1800m, 1500, 1200, 900m, 600m, 500m, 400m,300m,200m.
Have two copies, one either seat.
These numbers can be obtained from the "tables and codes" off your jepps.
Many new FMS have a conversion page, for FL Mts; and have a page for QFE conversion of Hps, Mtrs and Ft, for QFE and QNH.
As a back up also note the Mm altimeter setting for QFE, and verify. It is not unknown for the Hps numbers to be transposed, by non first language controllers working in English.
Lastly all I can say is take your time, and verify ALL conversions.
Have a great Moscow experience.
PM if more info needed, or even a hand holder.
Windy
Take the published airport elevation, and divide by 30. This gives a very close Hps to be added to the QFE. The Russian system normally provides a QFE. This gives the QNH.
There are several discussions that suggest working in GFE or in QNH when working in Ruiisa.
Most FMS display the runway evelvation, if feet; so will show 690ft for example on 24 at VNO.
Many operators deduct 690 ft, or use the Jepp published plate QFE value, and input in the FMS, for all values below the Transition, either 1500mt or 1800mt.
I would strongly recomend creation of a laminated data sheet, to fit on the control wheel chart data sheet, with BIG numbers.
This data sheet showing the relevent FL in feet to FL in meters. and show 1800m, 1500, 1200, 900m, 600m, 500m, 400m,300m,200m.
Have two copies, one either seat.
These numbers can be obtained from the "tables and codes" off your jepps.
Many new FMS have a conversion page, for FL Mts; and have a page for QFE conversion of Hps, Mtrs and Ft, for QFE and QNH.
As a back up also note the Mm altimeter setting for QFE, and verify. It is not unknown for the Hps numbers to be transposed, by non first language controllers working in English.
Lastly all I can say is take your time, and verify ALL conversions.
Have a great Moscow experience.
PM if more info needed, or even a hand holder.
Windy
Last edited by Itswindyout; 21st September 2006 at 08:39. Reason: cos I can
