QNH and QFE ?

PPL Training

QNH and QFE ?

Pete Murphy 22/05/2003, 9:16 PM
Hi All,

Appologies in advance if this is a dumb question ;-)

I've just recently started learning to Fly ( Approx 4 lessons so far ) and i'm finding a few
things difficult to grasp like QNH and QFE pressure settings and what these things
actually do and mean.

As i've only just begun my training is it to early to start worrying about these
pressure settings ? or is it a good idea to try to learn about them ASAP ??

Does anyone know of any good web sites or books that explain these in a easy
to understand way as i can't seem to get my head round these things.

Thanks

Pete.

Re: QNH and QFE ?

Darren Wheeler 23/05/2003, 12:11 AM
No such thing as a dumb question -- we all have to learn somewhere.

QNH - when this pressure is set on your altimeter it will give you your altitude above mean sea level in your area. As all aeronautical charts show elevation in feet amsl this is the one to use to make sure you're going to be above terrain or obstacles (such as TV masts).

QFE - with this set your altimeter will read 0ft on landing. It gives you your height above the airfield for which that particular pressure is valid. At your stage of the game you might want to set this for flying in the circuit so that you can fly at circuit height (which are always given based on QFE in the UK).

See - easy :-))

Re: QNH and QFE ?

Jane Giffould 23/05/2003, 12:14 AM
Don't worry Pete. Concentrate on the flying for the moment. There is so much to learn that if you try to take it all on board at once you will be way beyond the MTOW (Maximum Take Off Weight). When you are ready your instructor will start introducing the terms that you need to know and will get you started on the ground school. There are various series of books that people use as their background, again do not try to read them all at once, you should be reading the one about flying, keeping that machine straight and level etc. There are 2 main series of books, one lot by Thom and one lot by Pratt. From what I gather Thom is more academic than Pratt. It depends how you like the work to be presented. I was quite happy with Thom. But again consult your instructor/others at the flying school.

And as to QNH and QFE. QNH is the air pressure as at sea level. (Normal Height) It is important to know that and have that on your altimeter. It is what everyone else will be using and it regulates your altimeter to show how high you are. As the air pressure changes so your altitude will appear to change as the altimeter is calibrated for altitudes being at a specific pressure. You can then change that setting to fit in with the actual pressure. QFE refers to Field Elevation. Most airfields are not at sealevel and hence your height above the airfield will not be the same as at sea level. Rather than having to do calcuations to figure your height above the runway this can be done by putting in the airpressure at the runway and so trimming the altimeter to record height above ground rather than altitude above sea level. Some countries do not bother with QFE but leave you to do the calculations, which are not too difficult and one has to do them in this country at times if one does not have the QFE for an airfield.

Sorry if it all looks long and complicated. Eventually you will get used to it. Just practice. But remember it is the aviation that comes first.

Re: QNH and QFE ?

Pete Murphy 23/05/2003, 6:18 PM
Thanks Darren,

I think it's a bit like trying to run before i can walk scenario.
I'm really enjoying it and i think i should've done it a few years
ago, but it seems like there is a lot to take in and i'm not sure
my brain will be able to take it ;-)

I hope i can soon get the hang of it, once again thanks for your
reply.

Pete.

Re: QNH and QFE ?

Pete Murphy 23/05/2003, 6:29 PM
Hi Jane thanks for your reply,

I know i've got a lot to learn but my instructor has told me to start looking
at the Air Law book ( by Pratt ) and it's seem to me you've got to know this
stuff like the back of your hand.

The reason i was asking about QNH and QFE, is that it pops up quite a few times
in this book and i don't really like reading on any further if i don't know what they
are talking about, did you ever feel the same ???

Pete

Re: QNH and QFE ?

Jane Giffould 24/05/2003, 12:00 AM
Hence why I would ask questions of the instructors, I managed to get through quite a lot of instructors. I also went to the ground school courses run by the airclub. And I still ask questions. The more one knows the more one knows one does not know!! But on reading sometimes the answers to what one is stuck on come up as you read on. eg: QNH and QFE come up under altimeter setting procedures in Air Law, they also come up under Air Nav. They come up everytime you fly when you do your taxi call and when you do your join request call. You may hear changes of QNH over the radio whilst flying. Important then to reset the altimeter especially if you have any mountains littered around you. But your instructor will work on this with you.

Keep enjoying yourself.

Re: QNH and QFE ?

Pete Murphy 24/05/2003, 11:52 AM
Thanks again Jane for your advice,

No doubt i'll find some other things to worry me in the near future.

With all this new stuff going on around me i even forget to keep a look
out, i mean to but when my instructor is telling me things to do i have
a tendency to keep looking at the Flight Instruments instead of trying to
keep a look out in the area we are Flying and on the horizon.

Once again thanks.

Pete

Re: QNH and QFE ?

Norman Braithwaite 24/05/2003, 12:39 PM
"No doubt i'll find some other things to worry me in the near future."

You will, Pete. The trouble is (at least with the Pratt series), that some of the books use jargon you don't learn about until you read other books.

So you end up asking questions that are incredibly basic, but not dumb given the way the books are written.

The one that had me fooled was "Squawk 1234 Mode Charlie". Don't even ask what it means yet.

I'm with Jane. Ask your instructor. If he makes you feel that the question is stupid, then move to another instructor. When you find one that doesn't, stay with her ;-)

Re: QNH and QFE ?

Pete Murphy 24/05/2003, 2:03 PM
Hi Norman,

I won't even begin to think about asking you what that means ;-)

I've had three instructors so far ( not bad for only four lessons eh ? )
Seriously though they seem to be good instructors and they've answered
all of my questions so far.

The one I've got now he seems pretty helpful and I feel very comfortable
with him and at ease, I'd like to stay with him if possible for a while to see
how it goes. I think you build some sort of a relationship with your flying
instructor don't you ? and I think this is important you do as he makes me
feel confident and I've been told off a few qualified Pilots that confidence
is a major issue in learning to Fly, do you agree ?

I've been told that the ground school I will get is all included with the lessons,
plus they run some sort of class room based instruction a couple of times a
month and I will attend those if possible, I don't really consider my self a bad
student, if I've got to study things I will do it, I will always make time to do the
study as my Flying Instructor has told me, I won't pass the PPL by just throwing
money at it, as he's had some students who have thought that.

I think it's like anything else really if you put in the effort you will get the rewards
hopefully, I know it's not a race and from a personal point of view I'm not really
bothered how long it takes just as long I can become a Safe and competent Pilot
and the end of it all and then take it from there.

Pete

QNH and QFE ?

Mark Farquhar 26/05/2003, 10:29 PM
Hi - just wanted to make a little addition to what the others have all ready rightly said. When I was learning that part of the sylabus my instructor gave me a fantsatic little way of remembering the difference.

QNH - Q Nautical Height (height in respect of sea level)
QFE - Q Field Elevation (height in respect of the aerodrome)

Thinks of them as abbreviation for those definitions. Keeps it simple to learn!

Reguards Mark

Re: QNH and QFE ?

Pete Murphy 26/05/2003, 10:40 PM

Hi Mark,

Thanks for the Advice mate, any help or advice i get at the moment
is very much appreciated.

I think it'll all come with experience hopefully.

Cheers

Pete.

Re: QNH and QFE ?

Nicholas Avis 28/05/2003, 2:24 PM
Hi Pete

Hope this helps also. I've only just got my PPL so I know what you're going through, but hang in there as it'll soon click into place.

This is the way I eventually managed to grasp QNH and QFE:

Imagine you're on the ground at an aerodrome which is, say, 200 feet above sea level. If you adjust the altimeter so that it reads zero height, it is now set to QFE.

If you then adjust the altimeter to read the aerodrome elevation (200 feet in this case), it is now set to QNH.

Maybe you can do this exercise with your instructor just before your next flight?

Cheers - Nick

Re: QNH and QFE ?

Pete Murphy 28/05/2003, 4:39 PM

Hi Nick,

Congrats on getting your PPL, how long did it take you ?

Thanks for the advice, it seems to be getting better now, the more I've read about
Flying in general.

I know I've got a lot to learn but it doesn't seem to be as daunting as it was a few
weeks ago, as I've really done a lot of studying and things are starting to make sense
albeit slowly, but it isn't a race is it ?

Thanks again

Pete

Re: QNH and QFE ?

Nick Thompson 30/05/2003, 12:37 AM
I wasted so much time and money with a different instructor almost every time I went for a lesson.
I would advise making a bid at a concentrated course, either in the UK or overseas. I started my first PPL effort in the UK; it took years and cost a lot of money. I entually finished it in Qatar where I had the time to go when I wanted.
For about 20 years after that I did not fly and then decided to get back into it. I thought good and hard about how I would do it. I went to the US and got it back in 4 weeks. It was like starting from scratch and being 20 years older I found it harder to study, but much easier than the first time. I hate to think how much time and money I wasted the first time round.
It is so important to get an instrutor that you get on with, you may as well give up if you don't get on together.
Concetrating on flying and flying studies on a short course, makes it much easier as you don't have to try and remember what you did on the last lesson. You will also be working with lots of other people 'in the same boat' and will learn to help each other - it works!

Good Luck, NICK

Re: QNH and QFE ?

Pete Murphy 31/05/2003, 10:41 AM

Thanks Nick.

Pete

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