Re: Boeing 737 crash

From:         "P.J. Bunyon" <P.J.Bunyon@newcastle.ac.uk>
Date:         01 Feb 95 02:16:21 
References:   1
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On 29 Jan 1995, Ian Urquhart wrote:

> Please excuse my ignorance but what is QNH and QFE?  I hold a US 
> commercial certificate and instrument rating and have not come across 
> these terms.  There is only one altimeter setting and that's it. 
> Simple.  Do Canadian pilots deal with this QNH and QFE business? 
> Just interested.

	QFE is the atmospheric pressure at AERODROME level. With this 
set, the altimeter shows your HEIGHT above the aerodrome. QNH is the 
atmospheric pressure at MEAN SEA LEVEL. With this set, the altimeter 
shows your ALTITUDE above MEAN SEA LEVEL. On a normal flight, you would 
take off with QNH set as this would give your altitude above sea level. 
The exception to this is if you're staying in the circuit, when your 
height above the aerodrome is more important. When approaching your 
destination aerodrome, if flying visually, you would change to the QFE 
when the field was in sight and then let down.

	Hope this helps, Pete.