About the altimeter setting
Joined: Oct 2010
Posts: 346
Likes: 1
From: USA
Hinhin, your main lesson from the thread should be that if you ever fly in the UK, you will be facing entrenched irrationality, regulatory stupidity, and impractical complexity on a level that most American pilots would find inconceivable. Be glad that you don't need to remember 19th century Q-codes and good luck with your (one) written exam!
Joined: Dec 1998
Posts: 4,282
Likes: 6
From: Escapee from Ultima Thule
Above the Clouds, 'A' is correct. Temperature correction for True Altitude only applies to the *air* column, and not any Terra Firma between the bottom of the column and sea level.
Charliegolf, you can fly across the US without submitting any form of flightplan and not talk to anyone provided you avoid D, C, B & A airspace. If within 30nm of certain designated airports then you must have a transmitting Mode C transponder (but still needn't talk to the controller if you stay outside the controlled airspace.
Most of the country is Class G or E. To a VFR pilot Class E is transparent unless you avail yourself of radar advisory services. If, while VFR in Class E, you choose to communicate with a controller then you must obey the controller's instructions, no different to other airspace.
Charliegolf, you can fly across the US without submitting any form of flightplan and not talk to anyone provided you avoid D, C, B & A airspace. If within 30nm of certain designated airports then you must have a transmitting Mode C transponder (but still needn't talk to the controller if you stay outside the controlled airspace.
Most of the country is Class G or E. To a VFR pilot Class E is transparent unless you avail yourself of radar advisory services. If, while VFR in Class E, you choose to communicate with a controller then you must obey the controller's instructions, no different to other airspace.
Joined: Dec 2015
Posts: 200
Likes: 9
From: U.K.
Interesting.......
I set QNH before taking off, as it's easiest to do it then, and I can confirm it's right as I know the field elevation above mean sea level.
QNH = Newlyn Harbour = Sea level !
On returning to an airfield, you know those pre landing checks, where you say "instruments", that reminds me to set QFE for that airfield.
All very simple really.
EXCEPT
came unstuck the other day, "cleared to transit the overhead not below height 2500' "
and I was on QNH and I selected 2800, and the airfield was >300' amsl. Oops.
I set QNH before taking off, as it's easiest to do it then, and I can confirm it's right as I know the field elevation above mean sea level.
QNH = Newlyn Harbour = Sea level !
On returning to an airfield, you know those pre landing checks, where you say "instruments", that reminds me to set QFE for that airfield.
All very simple really.
EXCEPT
came unstuck the other day, "cleared to transit the overhead not below height 2500' "
and I was on QNH and I selected 2800, and the airfield was >300' amsl. Oops.
Joined: May 2010
Posts: 1,093
Likes: 9
From: UK
<Rant>
When are we finally going to consign this QFE nonsense to the dustbin of obscure aviation history where it belongs.
It serves no usefull purpose, causes confusion and incorrct altimeter settings are a major cause of accidents.
Move transition altitude to a sensible consistent standard of 19000 feet and we would have a simple and safer system of QNH for everthing below 19000 where we have plenty of time to twiddle knobs and 1013 above.
</rant>
When are we finally going to consign this QFE nonsense to the dustbin of obscure aviation history where it belongs.
It serves no usefull purpose, causes confusion and incorrct altimeter settings are a major cause of accidents.
Move transition altitude to a sensible consistent standard of 19000 feet and we would have a simple and safer system of QNH for everthing below 19000 where we have plenty of time to twiddle knobs and 1013 above.
</rant>
Joined: Jan 2011
Posts: 1,032
Likes: 0
From: In an ever changing place
The Ancient Geek
When are we finally going to consign this QFE nonsense to the dustbin of obscure aviation history where it belongs.
It serves no usefull purpose, causes confusion and incorrct altimeter settings are a major cause of accidents.
Move transition altitude to a sensible consistent standard of 19000 feet and we would have a simple and safer system of QNH for everthing below 19000 where we have plenty of time to twiddle knobs and 1013 above.
When are we finally going to consign this QFE nonsense to the dustbin of obscure aviation history where it belongs.
It serves no usefull purpose, causes confusion and incorrct altimeter settings are a major cause of accidents.
Move transition altitude to a sensible consistent standard of 19000 feet and we would have a simple and safer system of QNH for everthing below 19000 where we have plenty of time to twiddle knobs and 1013 above.
Joined: Feb 2016
Posts: 165
Likes: 0
From: Greater London Area
Although the whole thing might be overtaken by geometric altitude - no messing around with pressure setting at all...
Joined: Dec 2003
Posts: 2,347
Likes: 838
From: Tring, UK
Why, what’s the problem with everyone working off the same datum?
It’s a bit like magnetic vs. true navigation. I’m not the slightest bit interested in what the Earth’s magnetic field is doing in various places - I just want to get from A to B in the most expeditious manner.
Geometric altitude gets rid of many of the errors that plague pressure altimetry, like temperature, lapse rate, variability and not least, transcription. No need to know the surface pressure. What’s not to like?
It’s a bit like magnetic vs. true navigation. I’m not the slightest bit interested in what the Earth’s magnetic field is doing in various places - I just want to get from A to B in the most expeditious manner.
Geometric altitude gets rid of many of the errors that plague pressure altimetry, like temperature, lapse rate, variability and not least, transcription. No need to know the surface pressure. What’s not to like?
Joined: Feb 2016
Posts: 165
Likes: 0
From: Greater London Area
Why, what’s the problem with everyone working off the same datum?
Geometric altitude gets rid of many of the errors that plague pressure altimetry, like temperature, lapse rate, variability and not least, transcription. No need to know the surface pressure. What’s not to like?
Joined: Jan 1999
Posts: 1,377
Likes: 174
From: England
The problem is political inertia. It takes the authorities ages to respond to technical advances. In an ideal world a decree would be issued by all aviation regulators:
On and after 01 January 2018 all altimetry and navigation will be GPS based.
No more TAs and magnetic navigation! Pressure altimeters (automatically set to local sea level air pressure via data link) and compasses (with local variation data available on EFIS displays) only for back-up.
On and after 01 January 2018 all altimetry and navigation will be GPS based.
No more TAs and magnetic navigation! Pressure altimeters (automatically set to local sea level air pressure via data link) and compasses (with local variation data available on EFIS displays) only for back-up.
Avoid imitations
Joined: Nov 2000
Aviation Qualifications: ATPL
Posts: 15,114
Likes: 1,088
From: Wandering the FIR and cyberspace often at highly unsociable times
<Rant>
When are we finally going to consign this QFE nonsense to the dustbin of obscure aviation history where it belongs.
It serves no usefull purpose, causes confusion and incorrct altimeter settings are a major cause of accidents.
Move transition altitude to a sensible consistent standard of 19000 feet and we would have a simple and safer system of QNH for everthing below 19000 where we have plenty of time to twiddle knobs and 1013 above.
</rant>
When are we finally going to consign this QFE nonsense to the dustbin of obscure aviation history where it belongs.
It serves no usefull purpose, causes confusion and incorrct altimeter settings are a major cause of accidents.
Move transition altitude to a sensible consistent standard of 19000 feet and we would have a simple and safer system of QNH for everthing below 19000 where we have plenty of time to twiddle knobs and 1013 above.
</rant>
Joined: Dec 2003
Posts: 2,347
Likes: 838
From: Tring, UK
My plane flies on pressure and air flow, not strict mathematical geometry. I prefer an altitude with a relationship to the physics of flying, not artificial rulers and dividers. If I get a QNH is does not only tell me about heights, it does tell me more on the things I have to expect when piloting - it connects to your guts feeling. I prefer an intuitional connection to the air outside.
There’s nothing wrong with knowing the surface pressure as well but for vertical navigation, accuracy and commonality are important for separating aircraft from each other and from the ground. CAT III GBAS is due in a year or two which is amazing progress for aviation. Ever since GPS was invented it has been accurate enough for en-route navigation.
Better not mention FBW!
Joined: Jun 2001
Posts: 3,991
Likes: 8
From: UK
There's nothing to prevent you as an individual flying on QNH rather than QFE.