And is this a typical UK thing, or are controllers anywhere in the world supposed to give me the QNE when I ask for it?

I can tell you what QNE is; 1013.25 hectopascals. Thought you would have known that...:)

Aw, Dave, QNE is a level, not a pressure setting. Thought you would have known that… :) (Was my instructing at EGLF wasted… ;) )

So what is the calculation/formula please? 1013.2 - QNH X 30ft + elevation? Serious question by the way!

I am confused now, which I must confess is easily done.

Do I get it right?
 

OK, I'll tell everyone what I've understood. Unlike QNH and QFE which are altimeter settings, QNE is an altimeter reading - it is an indication on your altimeter at landing when you set it to 1013.2/29.92. Of course it is as changeable as QNH and QFE, so you need to get it each time from someone. And then, when landing:

• instead of setting QNH on alt and reading THR elev when you land, and
• instead of setting QFE on alt and reading 0 when you land,
• you set standard setting 1013.2 and read QNE when you land.

Did I get it right?


To answer a question from Crash one I'll now put my Math MSc hat on:

• I just derived on the back of an envelope that QNE = (1013.2 - QFE) x 30, but:
• QFE = QNH - (elevation/30), so:
• QNE = (1013.2 - QNH) x 30 + elevation

Quod Erat Demonstrandum :cool: You just missed brackets :E


/h88

Thank you I did remember the brackets but too late. Must try harder !!

Therefore: Leuchars QNH at this time is 958hectobars. If I were to land at Kingsmuir, elevation 398 ft altimeter should read 2114ft (using what should have been QNH) ?

Please refer to CAP493 Annex A Page 2.

Crash one, you would need to obtain/calculate/deduce a QFE for Kingsmuir. If using the Leuchars QNH then the Kingsmuir QFE might be approximately 14 hPa lower, ie. approximately 944 hPa, and possibly off the subscale. From the table QFE 944 hPa gives a QNE of 1946 ft, ie. the altimeter would indicate approximately 1946 ft on landing.

Correct.

Dave, a QNE is not a pressure setting. If you are the Dave Wilson I trained at Farnborough in the early eighties you have since become a very experienced GA pilot, so should therefore know this!

That's the second time in about an hour I've been mistaken for someone else in two different threads! I'm Dave Wilson of no fame whatsoever. It's a very common name believe it or not. In fact my full name is David John Wilson and there was anothe DJW of the same rank on 3Sqdn when I was there. Caused no amount of hilarity. The chap on the other thread thinks I am one Whizz Wilson of Australia.

Me. Not to be confused with more famous Dave Wilsons.

http://i1081.photobucket.com/albums/...ps26c330b4.jpg

So if I'm asked to set QNE when flying IFR exactly what pressure setting do I set on the subscale? Have I been flying at the wrong FL all this time?

Mis-ident. Us ATCOs do that occasionally. Use full callsign.

Anyway, he was better-looking than you. Probably because of that sprout soup, it doesn't look very appetising.

1013.2 hPa. It's not a QNH, not a QFE, nor a QNE. it's SPS.

Greetings to all in Season.

At risk of sounding stupid, no I'll rephrase, sounding stupid, exactly what is QNE? I've been flying all of this time, IFR and VFR and not known what it is. Methinks there was a gap in my training somewhere.

From CAP413:

:ugh:

Clocks off… :zzz:

Ah, got it now. I thought you were saying QNE wasn't 1013.25.

I know it's not, I know what you mean by it's not 1013.25. But it is in the backwards way I'm looking at it. We are all clear now, just a syntax problem.

It's actually snails in garlic during a visit to Le Touquet earlier this year. Wouldn't recommend but tick in the box and all that.

See CAP 493 and search for QNE or go to the 342nd page. There is a table for ATC staff to convert a QFE to a QNE when QFE is between 970 and 900. Value is the reading on an altimeter set to SPS.

I once had the altimeter knob come off on approach to Oxford - I got the ATIS, found I couldn't set the QNH (I'd been on regional pressure so quite a few mB different), switched to Approach, informed them, and could hear quite clearly even from 10 miles or so out the scratching of heads as they tried to work out the circuit indicated altitude I should fly to put me at 1200ft QNH.

To be fair to them, it only took them about 30 seconds to come back with an answer which I think was correct (seemed to work, anyway!).

The other thing to watch out for is taking off from a high airfield underneath airspace with QFE set. Crosland Moor at Huddersfield is a good one for that, there's class A at 3,500 and class D at 3,000. Field is at 800 odd feet, easy to forget on the climb out, seen it happen.

Just for the record a millibar change on the altimeter sub scale is worth 27.3 feet - 30 feet is an approximation

Doesn't that decrease as you go up?

Yes the formula is h=96T/P where h is foot per mb, T is Absolute Temp (deg C + 273) and P is pressure in mb.

However to work out QNE imagine you are on ground at an airport which is 1,000 ft amsl and the QNH is 963 mb so with 963 set the altimeter indicates 1,000 ft Now set 1013 - you are winding on 50 mb = 50 X 27.3 = 1365 ft The altimeter now reads 1,000+1365 = 2365 ft so this is QNE.

I stand to be corrected on this one but although the height change per mb changes with temp and pressure the change in indicated altitude will be the same for a given change in sub scale setting at different altitudes.

The answer to this problem is to discontinue use of QFE, as previously discussed in this thread.