QFE / QNH
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QFE / QNH
I am still very new to aviation so this may be a silly question...
I'm being instructed to use QNH on take off and QFE on landing, this makes sense to me because it's handy to know where 0ft is when your approaching a r/w.
A video on these forums shows a pilot landing with 300ft still on the AI, which suggests he is still using regional QNH. Is this normal practise, is it a UK specific thing to use QFE?
<EDIT 1> I understand I should have said QNH and not Regional QNH
<EDIT 2> This thread could now also be titled, how to fly with QFE and not die!
Cheers
Sparky
I'm being instructed to use QNH on take off and QFE on landing, this makes sense to me because it's handy to know where 0ft is when your approaching a r/w.
A video on these forums shows a pilot landing with 300ft still on the AI, which suggests he is still using regional QNH. Is this normal practise, is it a UK specific thing to use QFE?
<EDIT 1> I understand I should have said QNH and not Regional QNH
<EDIT 2> This thread could now also be titled, how to fly with QFE and not die!
Cheers
Sparky
Last edited by SparkyBoy; 5th Jul 2006 at 11:02.
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Sparky
I guess this will be pilot specific, the more experienced pilot may wish to use Airfield QNH (as opposed Regional as you stated), it could have been a case where he had forgot to set QFE, in the grand scheme of things as long as you are comfortable with whichever you use then I see no problems, however, student pilots & inexperienced pilots alike would be well advised to use the system they were taught by their instructors
Dean
I guess this will be pilot specific, the more experienced pilot may wish to use Airfield QNH (as opposed Regional as you stated), it could have been a case where he had forgot to set QFE, in the grand scheme of things as long as you are comfortable with whichever you use then I see no problems, however, student pilots & inexperienced pilots alike would be well advised to use the system they were taught by their instructors
Dean
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It depends on the airfield in question. For example, one airfield that I know always uses QNH and the circuit altitude is published as 1200'. As the airfield elevation is approx 200' this represents a circuit height of 1000' above ground level. Another I know uses QFE, but it is only around 50' above sea level. I suppose that that must be the reason for the choice between the two.
Your man with 300' on the clock should have been using the local i.e. airfield's QNH, not the regional setting.
Your man with 300' on the clock should have been using the local i.e. airfield's QNH, not the regional setting.
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QFE is a silly thing which is used only (as far as I know) in the UK. It is really confusing and should be abolished.
If a pilot can't work out how high he should be if required to be say 1000ft above the airfield elevation then it's amazing he ever got through the PPL exams. If the elevation is say 1200ft then he needs to be there at 2200ft. This is no rocket science, and avoids the mistakes caused by flying with QFE instead of QNH.
The other benefit of flying on QNH is that the altimeter always reads the altitude, which then relates to obstacle heights shown on the charts. So you have, right in front of you, a constant readout which gives you information on obstacle clearance. QFE is completely useless for anything en-route.
It gets much worse if instrument flying. Easy to make a fatal error then, if getting the two mixed up. So instrument pilots usually use QNH only.
Does anyone know why the UK hangs onto QFE?
If a pilot can't work out how high he should be if required to be say 1000ft above the airfield elevation then it's amazing he ever got through the PPL exams. If the elevation is say 1200ft then he needs to be there at 2200ft. This is no rocket science, and avoids the mistakes caused by flying with QFE instead of QNH.
The other benefit of flying on QNH is that the altimeter always reads the altitude, which then relates to obstacle heights shown on the charts. So you have, right in front of you, a constant readout which gives you information on obstacle clearance. QFE is completely useless for anything en-route.
It gets much worse if instrument flying. Easy to make a fatal error then, if getting the two mixed up. So instrument pilots usually use QNH only.
Does anyone know why the UK hangs onto QFE?
aceatco, retired
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Originally Posted by littco
We hang onto the QFE as it HAS to be used for precision approaches.
Under JAR regs, companies normally use QNH when flying precision approaches ie PAR/ILS, however QFE is available on request to ATC.
I believe QFE is only used in the UK and somewhere in the Indian Ocean (Mauritius?), the rest of the world uses QNH below TL. And the UK only uses QFE because the RAF insist on it (that'll stir it up!)
I believe QFE is only used in the UK and somewhere in the Indian Ocean (Mauritius?), the rest of the world uses QNH below TL. And the UK only uses QFE because the RAF insist on it (that'll stir it up!)
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I had some years back asked on the military forum why the RAFuse QFE and don't want to change, I did not get a conclusive answer but the jist of it seems to be that it keeps the cockpit workload down for the fast jet pilots when doing PAR recoverys in bad weather ( no ILS fitted to some fast jets).
I can see the reasoning as these guys sometimes have to fly in very bad weather and using fuel reserves that would make a civilian pilots eye water.
From a civilian point of veiw I agree with IO-540 that the QFE/QNH switch during single pilot I.F. is an accident going somewhere to happen.
I can see the reasoning as these guys sometimes have to fly in very bad weather and using fuel reserves that would make a civilian pilots eye water.
From a civilian point of veiw I agree with IO-540 that the QFE/QNH switch during single pilot I.F. is an accident going somewhere to happen.
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I still don't see the need for QFE, especially on a PAR approach where you get guidance in both planes.
Actually I do wonder what real-world capability the RAF has these days. Any dirty work of any significance has to be contracted out to the Americans.
Recently (1-2 yrs ago) I read a press release from Skyforce (now owned by Honeywell) saying the RAF have just bought a couple of hundred of their Skymap II GPSs. Well, I have one of those from my PPL self-fly-hire-a-piece-of-junk days and it now lives in my emergency bag. If the RAF are using that sort of technology, they are doing well to navigate to Odiham at 500kt
Unfortunately, so many people have retired from the RAF only to join..... guess who? .... the CAA!
Actually I do wonder what real-world capability the RAF has these days. Any dirty work of any significance has to be contracted out to the Americans.
Recently (1-2 yrs ago) I read a press release from Skyforce (now owned by Honeywell) saying the RAF have just bought a couple of hundred of their Skymap II GPSs. Well, I have one of those from my PPL self-fly-hire-a-piece-of-junk days and it now lives in my emergency bag. If the RAF are using that sort of technology, they are doing well to navigate to Odiham at 500kt
Unfortunately, so many people have retired from the RAF only to join..... guess who? .... the CAA!
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I never use QFE. Waste of time and confusing for a lot of people. Instrument approaches I always fly in QNH and visual the same. I live inside a MATZ and that is the only time I use QFE and at that point it only really becomes another number for the crossing as I revert to QNH on exit and when approaching the runway.
QFE should be abolished.
QFE should be abolished.
I haven't got a clue why the RAF still use QFE either but it works. QNH also works. IMO it does not really matter what system you are using as long as you understand it.
I use QFE for take off and landing. I can understand the reasons for using QNH for take off but switching like that would confuse the hell out of me. What if you are doing circuits? Do you change the setting downwind? Do you change back again during the touch and go?
If you don't like QFE then don't use it. Simple. It has it's advantages but it's not for everyone. I frequently fly to civilian airfields where QNH is used but it is not a problem. Simply ask for the QFE.
IO540
I am pretty sure I know which units used the Skyforce GPS and if you do then you'd know they are extremely highly respected. If yours is no good then maybe there is a problem with the operator. True, it is not the best kit in the world but it does do what it says on the tin.
Why so Anti RAF anyway? Did they turn you down?
I use QFE for take off and landing. I can understand the reasons for using QNH for take off but switching like that would confuse the hell out of me. What if you are doing circuits? Do you change the setting downwind? Do you change back again during the touch and go?
If you don't like QFE then don't use it. Simple. It has it's advantages but it's not for everyone. I frequently fly to civilian airfields where QNH is used but it is not a problem. Simply ask for the QFE.
IO540
I am pretty sure I know which units used the Skyforce GPS and if you do then you'd know they are extremely highly respected. If yours is no good then maybe there is a problem with the operator. True, it is not the best kit in the world but it does do what it says on the tin.
Why so Anti RAF anyway? Did they turn you down?
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SAR bloke
You make a good argument for abolishing QFE.
The other problem is that some mil airfields won't give QNH even if you ask, EGOS (Shawbury) being one of them, not long ago.
The RAF didn't turn me down, no.
The other bit of stupidity is the regional pressure setting.
You make a good argument for abolishing QFE.
The other problem is that some mil airfields won't give QNH even if you ask, EGOS (Shawbury) being one of them, not long ago.
The RAF didn't turn me down, no.
The other bit of stupidity is the regional pressure setting.
I could give you reasons for the RAF keeping QFE but the ones I can come up with are mainly used for Fast Jet traffic in the circuit when the workload is very high. It is not as applicable for slower moving aircraft.
As for RPS. I would not give that up for anything. It may keep me alive one day.
As for RPS. I would not give that up for anything. It may keep me alive one day.
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Originally Posted by littco
We hang onto the QFE as it HAS to be used for precision approaches. Having said that if your aircraft has a radio altimeter then you would use this instead. I guess then it would only be used as a backup.
Not so. It certainly doesn't have to be used for precision approaches.We fly IFR whenever necessary and I can't think of one occasion where we have used QFE; all the IFR approaches at UK major airports are QNH based.
I'm not sure if it still happens but when the RAF reverted to using QFE many years ago after using QNH for a couple of years, they also abandoned use of local QNH, and their met forecasters probably don't even bother to calculate it now, so this would explain why IO540 couldn't get it from Shawbury.
System used was (and may still be) you departed on QFE, and changed to 1013 at TA; inbound at TL you changed back to QFE. If you ever went anywhere below TA, you set RPS.
System used was (and may still be) you departed on QFE, and changed to 1013 at TA; inbound at TL you changed back to QFE. If you ever went anywhere below TA, you set RPS.
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Originally Posted by littco
QNH can either be a regional pressure setting or a areodrome pressure setting.
If it is an aerodrome setting it will be at the highest elevation of the field.
QFE is QNH adjusted so that at the highest point the altimeter reads zero when on the ground.
Now, Not all airfields use QFE and those that do, normally have more precise landing proceedures like ILS etc where you will need an accurate height above the airfield elevation.
However you need to make sure that if the field is using QFE then you set your altimeter to QFE when entering the circuit otherwise you may find there could be 20mb difference between QFE and QNH and if your flying the wrong one you could be 500 ft lower or higher than you should be!
Littco - I think this demonstrates the farce that is the British ATPL system. You've obviously studied the exam matter by rote, without actually understanding the subject.
That, to me, is frightening!
This is one of those arguments that could go around for years and years.
The only time that I ever used QFE was when I was a guest of Her Majesty. Otherwise I agree with IO540 that QFE is a distraction and about as much use as a chocolate kettle.
Try setting QFE at Nairobi, Addis Ababa or Asmara!
I have done thousands and thousands of precision let downs all over the world using QNH.
My only regret is that it is difficult to find an airfield in UK that is prepared to give the QFF. Now that is much more accurate!
The only time that I ever used QFE was when I was a guest of Her Majesty. Otherwise I agree with IO540 that QFE is a distraction and about as much use as a chocolate kettle.
Try setting QFE at Nairobi, Addis Ababa or Asmara!
I have done thousands and thousands of precision let downs all over the world using QNH.
My only regret is that it is difficult to find an airfield in UK that is prepared to give the QFF. Now that is much more accurate!
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Chilli Monster,
Interesting Chilli. I was taught that QFF is a mean sea level pressure calculated using the actual temprature at the sensing point (as opposed to ISA for QNH). Apparently it is the pressure shown on met charts.
JW441,
To your knowledge is there anywhere, such as them there places, where QNE is actually used rather than just inhabiting a CAA examiner's head?
No - QFE is a pressure derived from QFF (pressure at sensing point) and is then calculated to give a barometric pressure in the touchdown zone of a particular runway.
JW441,
Try setting QFE at Nairobi, Addis Ababa or Asmara!
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What is your problem with QFE? particularly you mr IO540 does it matter what you have set, as long as you know where you are in the grand scheme of things it doesn't matter me feels.
Having flown both QFE/QNH mil ops I don't really care which I use and when operating at a civvy field and they ask me if I want a QFE approach as opposed to a QNH then again, dont really care. Just means I have to read a different number on the approach plate. If you are that easily confused then you probably shouldn't be a professional pilot, which is after all what this forum is about, the clue is in the title.
Variety is the spice of life chaps...............
If you don't like flying in MATZ's where they work on QFE, then don't.........do us all a favour
IO540 must know what he is talking about though as he flies aeroplanes where the wheels come up, wow how do you cope?
Having flown both QFE/QNH mil ops I don't really care which I use and when operating at a civvy field and they ask me if I want a QFE approach as opposed to a QNH then again, dont really care. Just means I have to read a different number on the approach plate. If you are that easily confused then you probably shouldn't be a professional pilot, which is after all what this forum is about, the clue is in the title.
Variety is the spice of life chaps...............
If you don't like flying in MATZ's where they work on QFE, then don't.........do us all a favour
IO540 must know what he is talking about though as he flies aeroplanes where the wheels come up, wow how do you cope?