Flying Approaches on QNH

[portsharbourflyer]

Always when landing at an aerodrome in the past, I have always set QFE, and it is what I would teach my students, however the school I work for has a policy that we and students should be taught to leave QNH set and even fly circuits and appoach to land with QNH set, not a problem at the "home" airfield because the qnh leads to a easy number for flying the circuit. However I feel for landing away at other aerodromes this could lead to confusion, ie; having to remember to add circuit height to local elevation in order to fly the correct circuit height if using the QNH. If flying cross country on a regional pressure setting you would need to reset to the aerodrome QNH,so why not just reset to QFE when inbound. This could be especially misleading flying (that is flying on the QNH) into a high airfield such as Dunkeswell or Compton Abbas.



Just wondering what anyone elses opinion is on this policy? Or am just showing my inexperience as an instructor.

[Say again s l o w l y]

Do you have altimeter bug's? If not, then it is far better to go to QFE when necessary.

Airlines use QNH as a means of keeping terrain clearance simpler, but it does require a bit more mental gymnastics if you try and fly a 1000' agl circuit, as is the norm in GA.

It can just create confusion which can be minimised by sticking to QFE approaches as the rest of the industry uses.

Sticking to standard practices can help cut down confusion.

[DFC]

It can just create confusion which can be minimised by sticking to QFE approaches as the rest of the industry uses.
Sticking to standard practices can help cut down confusion.

That little bit of the industry where you live perhaps. QFE is unheard of in the greather part of the world. In large parts of the world, it is not possible to set QFE.

Use something that you can use everywhere, can always obtain and will always clearly show your altitude that you can compare to obstacles. Even the obstacles on aerodrome charts are shown AMSL.

As for confusion. Some airfields have circuit height of 800ft, some 1000ft, one I know is 1200ft and another uses 600ft, while yet another uses 1500ft and all are in the southern central part of England.

Prior to operating to another airfield, a pilot should note the level required for the circuit. It is simply a number that they will try to fly at on the altimeter. If that figure is 1700ft QNH then where is the confusion.

The only time I got close to obstacles was flying with a pilot who used QFE but forgot to set the altimeter joining the circuit resulting in the aircraft being 600ft lower than it should have been downwind. With a 800ft AAL downwind level, one would have expected the proximity of the trees and ground to be ringing alarm bells but no, they even initiated their descent out on base leg!..........all on a VFR flight! :eek:

Regards,

DFC

[portsharbourflyer]

Thanks for the replies, good arguments either way, however lets keep this in context, it is ppl students we are instructing here flying in the UK and france, so QFE is always available.

[Tinstaafl]

What's their being a PPL student got to do with it? As was indicated earlier, elsewhere in the world QNH is used by everyone.

At least everyone's on a common setting, including transiting a/c. Even if one or the other is using a 'local' QNH & others an 'area' or 'regional' QNH the difference is minor. I know of no chart in common use that gives terrain w.r.t. QFE so what do you use during departure or arrival? What about mixing IFR & VFR traffic etc?

[Keygrip]

add circuit height to local elevation in order to fly the correct circuit height if using the QNH

That would be circuit ALTITUDE if adding circuit height to elevation and setting QNH, not circuit HEIGHT.

'regional' QNH I'm told there's no such animal...it's a "regional pressure setting".

[SASless]

QFE altimeter settings....yet another UK practice that begs belief.

If one uses QNH only.....that is one less mistake to make.

Yes I know the mental gymnastics of figuring the DH on an ILS is a tremendous burden for some but looking for 551 vice 0 ain't exactly rocket science.

Ever done the dance of setting three altimeters on an IF approach....compounded by a change in handling pilots during the Missed?

Then you have to remember which altimeter is set to what.....just like the old pea under walnut shell game.:ugh:

[Say again s l o w l y]

In the U.K, the vast majority of GA uses QFE. It does cause problems with people not changing to it when arriving at a field and other similar situations, but it is the norm here.

DFC, don't be facetious, we all know they are a multitude of differing cct heights in use, but most are at 1000'. The confusion comes, because there is not an easy way of working out your height, or how far you have to descend. Simple on QFE, but with QNH you need to think about it, whilst we are talking about VFR flight, why introduce an element of uncertainty?

I don't like changes being forced on people which aren't standard in this environment, unless there is a really good reason, otherwise it is a waste of time. PPL members used to QFE will ignore it. New students will use it, but you then have a situation where half are doing one thing and half doing something else leading ultimately to confusion somewhere along the line.

I can understand the reasons for it. I have operated on both QNH and QFE with an airline and whilst I understand all the arguments for and against, I prefered approaching on QFE, but very quickly got used to QNH, though it really required altimeter bug's on approach to try and minimise the brainwork.

However, if someone is taught from day one to use QNH only, then fine, it is only an issue if you try and force occasional flyers into a new way of thinking. You are asking for trouble there.

For IMC/IR, what does the school use?

It sounds like this has been an edict from on high and making changes like this without discussion or explanation is not good practice. If the FI's aren't sure why they are doing it, then what chance to they have when a PPL demands an explanation to the change. In this case it seems to be "'cos I was told to" rather than having coherent reasoning behind the change.

[BizJetJock]

Over more than 20 years I have used both QNH and QFE, and personally I prefer QNH. For VFR it doesn't really make a lot of difference, especially when the circuit height is 1000' - particularly with a "round dial" altimeter. When flying IFR approaches (other than Cat III!) I've never yet seen a procedure with a DH of 0 - so all this nonsense about not having to remember or bug your decision/minimum descent height is total b*ll*cks.
Finally, for the less well travelled there are equally large parts of the world where there is no such thing as QNH - you transition from standard to QFE and back, usually using metres as well.
The absolute bottom line is that as long as the procedures are followed any of the systems work. You just need to make sure that you understand the system you are using. Human nature being what it is most people will swear that the system they were first taught is the only way to do it and anything else is the Devil's own invention!:eek:

[Say again s l o w l y]

Very true and exactly why suddenly changing the system in use is not the wisest course of action.

[DFC]

DFC, don't be facetious, we all know they are a multitude of differing cct heights in use, but most are at 1000'. The confusion comes, because there is not an easy way of working out your height, or how far you have to descend. Simple on QFE, but with QNH you need to think about it, whilst we are talking about VFR flight, why introduce an element of uncertainty?

But if what you say is true - that most circuit heights are 1000ft then is it not simply the case that when at circuit altitude, one will have to descend by 1000ft?

What VFR pilot descends from circuit altitude without being able to see the runway? One descends at the appropriate time at a rate that will cause the aircraft to land on the runway one is looking at. Can't be more simple!

Pilots who use QFE will generally depart using QNH. They will often plan the following;

Flaps up at 300ft AGL, turn at 500ft AGL, fuel pumps off at 1000ft AGL.

They then actually complete the above at 300ft AMSL, 500ft AMSL and 1000ft AMSL despite the aerodrome and terrain being some 200ft AMSL.

-----------
Thanks for the replies, good arguments either way, however lets keep this in context, it is ppl students we are instructing here flying in the UK and france, so QFE is always available.

No. Some of us train PPLs to operate in accordance with their licence privileges. :)

Regards,

DFC

[Say again s l o w l y]

There are other reasons for everybody in a circuit being at the same height, rather than just able to get the a/c on the deck safely, so why change a convention.
Especially as neither system is perfect.

My bigger concern is that the FI's at this school don't know why they are being asked to do something different.

[jb5000]

I've done a bit of flying in the UK and now New Zealand, where QFE is not used at all.

From my perspective I have found it simpler to not worry about QFE. In NZ there are a load of uncontrolled (and unattended) airfields so it is impossible to obtain a QFE, so everyone gets by on QNH.

I find the circuit altitude is easily found when you brief for the approach into a new airfield. The elevation is in the top corner of the plate so while you are still some miles away you can decide what your joining and circuit altitudes will be, then round it up to a reasonable figure (no point flying a circuit at 1184ft!). Couldn't be easier!

[A37575]

QFE enthusiasts. Very dicey stuff. Stick to QNH and it is much safer especially when map reading around hills when you can check your height against a known spot height. Although I have never used QFE except by default at a sea level aerodrome, I imagine changing to use QNH is something like using look-over spectacles for the first time. You eventually get used to it and never look back.

[Say again s l o w l y]

QFE is not "dicey" and QNH is not a panacea either.

Away from the field, QNH. At the field QFE. It's not rocket science......

[bookworm]

However I feel for landing away at other aerodromes this could lead to confusion, ie; having to remember to add circuit height to local elevation in order to fly the correct circuit height if using the QNH.

Students, and indeed pilots, in the rest of the world seem to manage this just fine.

If flying cross country on a regional pressure setting...

Now, why on earth would you want to do that? ;)

[idle stop]

Circuits, particularly with students: QFE.
Departure/Take-Off checks on sortie to leave circuit: QNH
Departing ATZ: FREDA or somesuch checks to confirm/set QNH
Rejoining ATZ: FREDA etc checks, so QNH to QFE.
Initial/Intermediate/Final IFR approach checks: QNH

Or whatever it says in your training manual/company Ops Manual.

I think this is the UK system. It's what's been expected of me over the past 35 years both mil and civ. (Having said which, I think we were doing PAR on QFE at MoD airfields and perhaps still are?)

[LEVC]

As far as i know only in France and in UK pilots fly QFE, the rest fly QNH.

In UK and in most of the french airports you'll have no problem.

Problem will arise when you try to fly an approach on QFE in a high elevation airport, say QNH is 1013 in an airport where elevation is 3000 feet, tell me how are you going to set QFE in an altimeter where in the kollsman window you can only set 960 mb and higher :confused: .


I have flown in several places, including France and UK, i had to use QFE, and in my opinion QNH is the best option.

The funny bit is that if you rquest QFE in most of the places (outside UK and France) it will take them more than a couple of seconds to provide you with it , because they wont be expecting your request in mos of the cases.

[BizJetJock]

As I said before, QFE isn't just a UK & France thing, go East and you find a whole universe where there is no QNH, and you get a similar reaction to the one you describe if you ask for QNH.
When the UK built aircraft, altimeters could be wound down to about 750 for that very reason. Nowadays all the instruments are US made and so are designed for their system, which isn't a problem in the UK as there are no airfields above 1000' amsl. As you say, when you go to higher parts it is a problem, which is one reason why I prefer using QNH these days. However, see my earlier comments about all the systems work if they're used properly, and human nature!

[SD.]

QFE is not "dicey" and QNH is not a panacea either.

Away from the field, QNH. At the field QFE. It's not rocket science......

Neither is looking at the map & adding the field elevation to your circuit height :rolleyes:

My local is 387' MSL and they like the left circuit to be flown at 800' AGL, it's a no-brainer that the student should be flying his/her circuits with the hands pointing to 1200'

I know which method is user friendly and hell of a lot safer where terrain is an issue.

[unfazed]

Changing from QNH to QFE on the approach = room for pilot error in mis setting numbers

Missed approach QFE back to QNH = more chance of "finger trouble" and increased workload / distraction

Alternative = Set QNH and fly to the approach plate QNH decision height or DA.:)

[sir.pratt]

qfe - never used it. like has been said - do the maths off the plate, and add 1000 to airfield elevation - bingo there's the circuit height. as all kiwis know, we can get 'area qnh' from christchurch or auckland control, which is good enough for all those unattended strips. i'd be reluctant to be flying out of somewhere like taupo (elev. 1335), with someone flying south on qfe, me flying in north on qnh. ouch

[Needlesplit]

Changing from QNH to QFE on the approach = room for pilot error in mis setting numbers

Missed approach QFE back to QNH = more chance of "finger trouble" and increased workload / distraction

Alternative = Set QNH and fly to the approach plate QNH decision height or DA.:)

This comes down to doing one of two simple things. Either do a bit of mental arithmetic and alter your Altimeter accordingly, or listen to a radio transmission and alter your Altimeter accordingly.

It is not only in the circuit that you are required to alter the subscale setting. If you do a MATZ penetration your clearance will include, for example, 'Fly at 1500 feet on the Waddington QFE' this requires you to reset your altimeter, when you are busy navigating, planning, listening, looking, flying etc etc etc. Anyone who feels they may not be able to do that successfully or have 'finger trouble' maybe shouldnt be up there. Compared to some of the other stuff we need to do correctly, a subscale change is a fairly minor 'procedure'.

In the military they taught us L.O.I. Limitation - Operation - Indication. That means when you operate something, switch, lever, altimeter, whatever - you should do it. Then CHECK its correct!:ugh:

NB: Incidentally the MATZ/QFE thing is in one of the airlaw exams!:ok:

Having said that my personal preference is for QFE. I know there are other procedures in other places but in the UK we have QFE and you can always access the information if you have radio contact with the field. In high places, winding several thousand feet off the altimiter is both a pain and an unnecessary distraction but in the UK its never very much. Furthermore, when you have altered it you can immediately check whether you were correct (LOI) not so easy with mental arithmetic!

Anyway, my two pennys now inserted I'll B:mad: R off and go flying!

regards

N/S:ok:

[sir.pratt]

With 150 - odd aerodromes in NZ and only some 15 controlled, and maybe another 10 with AWIB, using QFE would be nothing short of irresponsible down here.

Does any kiwi/aussie use it? And for a UK pilot, how do you set QFE when 5 miles out from an unattended aerodrome?

[Say again s l o w l y]

You either just adjust the pressure setting for the field elevation to give a rough QFE, or just use QNH. Since the UK is relatively flat (in comparison to the states for example) there are rarely many problems.

[Keygrip]

It's an interesting debate from two sides, I think.

I find all my Floridian flying is prety much height above ground and altitude above sea level, at the same time, no matter what setting I have in the window.....it's all so flat and, near as dammit, sea level.

When I wander across to Arizona, however, there are airfields at 1000', 1500' and 2000' amsl - and lumpy ground rising into the 4 or 5 thousands.

It does take some mental gymnastics when operating into the higher level airfields and, even more so when manoeuvring (stalling, I/F flying etc) over the lumpy bits, when 80% of the day to day flying is done in Florida.

Being able to GET a QFE and set it in the second altimeter as a cross check would be a comforting thing - but still operate the number one altimeter on QNH as discussed so many times in this thread.

I trained, and qualified for licence, in the world of set QFE, and did find the transition to operating QNH only, a little bit difficult at first - and fully understand the concerns of those who still favour it......however, now that I'm used to QNH only, and understand it better, it does make sense.

Bit that does scare me, to an extent, is that pilots are still talking (even in this thread) about setting QNH, adding 1,000' to airport elevation and determining circuit (or decision) HEIGHT. It's a :mad: ALTITUDE.

Confusion in communications - especially with a controller who does not use the same national first language as the pilot, may result in exactly the same sort of problem that the QNH only pilots are worried about - aircraft on different settings being at the same level.

You have to call it something - so why not get used to calling it the right thing, ALTITUDE.

[BillieBob]

Keygrip - you need to get out of the valley occasionally. Try SEZ at 4830ft or GCN at 6609ft. I'm old enough to remember when the most common cause of failure at the IRT was forgetting to set QNH on the go-around.

[Keygrip]

Would love to BB - but too far for a test and Mickey mouse gets most of my spare time.

[unfazed]

Needlesplit

Anyone who feels they may not be able to do that successfully or have 'finger trouble' maybe shouldnt be up there. Compared to some of the other stuff we need to do correctly, a subscale change is a fairly minor 'procedure'

I Understand your comment and yes I can set and check a subscale setting but the point I am making is that if you don't need to then why bother ?

Get rid of unnecessary tasks and boil it down to required essentials which will lead to more efficient and safer flying with less room for human error

If you think that humans are infallible have another look at the accident reports. My point is that we do make mistakes occasionally so anything that reduces the likelihood has got to be good

And yes I know that it is possible to screw up the maths but it is maths that a 5 year old could do :)

[LEVC]

In this whole universe east of the Urals you talk about they also use Meters for expressing altitude and height, Km/hour for speed , Meters per second for wind, and it does not seem to me all this makes the flying any easier or safer, in most cases it can make it more dificult and unsafe as you probably know .

[Keef]

I was taught QFE, because that is what PPLs did in those days. Then I did the IMC rating, and found that nasty little trap that if you fail to set QNH on the missed approach, you fail (I never did, but came oh so close!).

So I taught myself to fly QNH. Then I did a load of flying in California and Arizona, including Big Bear, Grand Canyon, and Sedona. That convinced me! There's no chance of setting a QFE for those places!

If a MATZ tells me to use QFE, I'll do so - but the other altimeter will be on QNH, so I know where I am versus local terrain.

[theresalwaysone]

You have just quoted the reason why QNH is now used by most airlines, it reduces ERROR CHAIN.

Its not your setting above the ground that important its the ground below the setting that kills you