Thread: air law confussing

Good morning to all, i see chris and hotdog have all ready beat me here.
hi guys hope all is well.

quick question i have managed to get my hands on a trevor thom air law manual and have had my head in it for the past 2 days. most of it makes sense but im bit confused on setting altimeter eg qhn and qfe. i was wondering if morbz could help me out to outline quickly what and how to use these different settingsd so i could bend my head around it

safe flying

Hello there!

Not a worry, airlaw will too come with experience so dont panic if your not fully absorbing it, it is dry so perhaps a bit of highlighting in the book of key points etc might make it stick a little easier!

Q codes for altimeters?

-QFE: If you are given a QFE to set on your altimeter the altimeter will show you how high you are above the aerodrome specifically, thus when you land with the QFE set your altimeter will be reading 0ft on the ground- dead simple right? If you have QFE set you refer to your read out as "Height". You will find you have the QFE set in the circuit in the UK

-QNH: The QNH shows your altitidue relative to sea level, so when you land with QNH set your altimeter will read the elevation of the aerodrome- because it's referencing itself to how high you are above the sea. You refer to the read out as "Altitude". (If you landed on the sea then your altimeter would read 0ft!). This is used during navigation outside the airfield's vicinity.

So to summarise- QFE set = Height above the runway & reads 0ft on the Runway / QNH set = Altitude above sea & reads the airport's elevation on touchdown

You have to just realise the altimeter is merely a pressure sensor and what it shows you in feet is either distance above the sea or distance above something specific such as the aerodrome depending on whether you set QNH/QFE.

Any easier? I've attached a very simple pic just drafted up on paint!

thanks hotdog thats cleared that up so you should set qfe on altimeter prior to take-off then when in flight do you switch to regional qfe or qhn and when would you use the standard setting

On takeoff its normal to set QFE if you are departing from one leg in the circuit and then enroute to your destination you set the QNH.

Or just set QNH on the ground and check the elevation matches the indicated altitude then during departure just allow for the extra altitude your altimeter will not be telling you.

Standard setting 1013 is usually set above the transition altitude which in the UK is 3000ft. You use this when reporting Flight Levels to ATC and when you are above this altitude normally.

hey jigglyjohnson, following up on what hotdog had told you. I have got a sheet that my instructor gave to me as I was confused just like you. I can't be bothered to scan it, but if you still want it I will bother.
Also does anyone know how much time I have after finishing the air law exam? I remember faintly that I have to finish all tests and hours within 18 months. Can someone refresh my mind?

taz

Cant remember exactly but Im fairly sure it is 18 months, give your flying school a ring

Thanks, I will