Altimeter confusion...

Everyone has to be on the same altimeter setting. Could you imagine the possible chaos?

Not really a big problem if ATC knows what they are doing. I've controlled a situation where one aircraft was flying with meters/QNH, one aircraft with meters/QFE and one with feet/QNH. ATC does the conversion work. Of course it adds a bit of workload to ATC and risk of confusion increases. Doesn't differ very much of a situation where two aircraft are on different sides of transition layer which then again is pretty normal.

In Russia it seems to still be normal procedure to give flight levels in feet but below transition level clearances are given in meters/QFE. QNH pressure given if asked.

Not really a big problem if ATC knows what they are doing. I've controlled a situation where one aircraft was flying with meters/QNH, one aircraft with meters/QFE and one with feet/QNH. ATC does the conversion work. Of course it adds a bit of workload to ATC and risk of confusion increases.

I thought ICAO standards existed to prevent such a scenario....

If ATC knows what they're doing... Good airmanship would dictate the use of QNH below TA. Anything else is non-standard and less safe.

Well I would say that ATC needs to anyway know what they are doing so nothing new there compared to all feet and QNH operations. If it is possible to have such a situation in the controllers operating area then he/she will be trained to do proper separations between aircraft using different altimeter units/settings. Goes well within the acceptable level of safety.

I trained and flew using QNH, but learned QFE as well. While QFE is dangerous in an environment dense with airports (because you'll have planes in the same airspace using different altimeter settings), it is still used in locations where airfields are more separated. The Caucasus is one of those regions that still uses QFE.

I know it was used in the UK at one point; in my flight school class we had a German exchange student who used the mnemonic "Queen F***s Easy" to remember what QFE represented.:megalol:

EDIT: The proof will be in the Nevada pudding, where you have 4 airports in the immediate Las Vegas area. That, and QNH is used in the USA.

QFE is less safe, no matter how much you want to say about it. It's less safe, so almost NO ONE in the world uses it. Also, ATC often isn't even responsible for separation. And often ATC doesn't fully know what they're doing. They're also human. Just like the pilots. Humans make mistakes. Humans might have stress. They may be overworked. Distracted. Overloaded. Having a bad day. Etc etc. Combine that with a civvie pilot flying around in his Cessna who can't be assed to intepret his altimeter so he just sets QFE because it's easier the altimeter reads a round number... Come on... You're a frigging pilot......... Act like one.

 

A bit provocative that last sentence, nothing personal to anyone, just how I think about the ridiculousness of QFE.

I'm not sure why you continue to spout such nonsense. QFE is used in the UK as a matter of course when flying in the VFR circuit, as well as by the RAF, and it serves us well.

I think it's silly that you all are arguing about something that is a simulation, not real. No real people. No real planes. Then gripe that QFE is not safe IRL. All I stated was it has real world uses, as well as others here. Don't like it? Don't use it or write your congressional leadership and complain. As for me, I have to fly to Jackson, MS. If you're on my flight please don't argue with me about QFE, please?

I'm not sure why you continue to spout such nonsense. QFE is used in the UK as a matter of course when flying in the VFR circuit, as well as by the RAF, and it serves us well.

That would depend on where you're doing circuits. If at any decent sized airport inside CAS then you will be given a VFR circuit clearance not above an altitude. Altitude = QNH.

And to those who would suggest that a controller would happily have QFE and QNH traffic close to each other and would personally calculate the differences, sod that, way to much like hard work. A controller will tell you to fly at an altitude, hence QNH. You may ask for QFE and use it for your own purposes, but if you are instructed to fly at an altitude (which you will be in the UK) then it's up to you as the pilot to adhere to your clearance.

QFE may be used at uncontrolled GA aerodromes but it certainly has no place in the commercial world. The only real value of QFE is to make a circuit look pretty on the altimeter. Probably why the RAF still use it, they like pretty things, like medals and stuff ;)

That would depend on where you're doing circuits. If at any decent sized airport inside CAS then you will be given a VFR circuit clearance not above an altitude. Altitude = QNH.

 

And to those who would suggest that a controller would happily have QFE and QNH traffic close to each other and would personally calculate the differences, sod that, way to much like hard work. A controller will tell you to fly at an altitude, hence QNH. You may ask for QFE and use it for your own purposes, but if you are instructed to fly at an altitude (which you will be in the UK) then it's up to you as the pilot to adhere to your clearance.

 

QFE may be used at uncontrolled GA aerodromes but it certainly has no place in the commercial world. The only real value of QFE is to make a circuit look pretty on the altimeter. Probably why the RAF still use it, they like pretty things, like medals and stuff ;)

Obviously you don't fly commercially. Approach profile altitudes are based on QFE. Try again.

Approach profile altitudes are based on QFE.

In other words, AGL. Any altitude "based on" QFE is simply height above ground level.

In other words, AGL. Any altitude "based on" QFE is simply height above ground level.

QFE is not AGL. QFE is field elevation altitude. You may think that "yeah airport is on the ground" but what if the approach goes over mountains or over valleys?

QFE is not AGL. QFE is field elevation altitude. You may think that "yeah airport is on the ground" but what if the approach goes over mountains or over valleys?

QNH sets the altimeter to field elevation. QFE sets the altimeter to read 0 on the ground at the airfield, therefore making any altimeter reading on QFE AGL.

QNH sets the altimeter to field elevation. QFE sets the altimeter to read 0 on the ground at the airfield, therefore making any altimeter reading on QFE AGL.

Yes, but only right above the airfield. If the airfield is for example in a valley, this is not true anymore anywhere else.

AGL as such is always true for any spot as it is measured constantly (i.e. radar).

Yes, but only right above the airfield. If the airfield is for example in a valley, this is not true anymore anywhere else.

 

AGL as such is always true for any spot as it is measured constantly (i.e. radar).

Exactly.

QNH sets the altimeter to field elevation. QFE sets the altimeter to read 0 on the ground at the airfield, therefore making any altimeter reading on QFE AGL.

Once again, you are confused. QNH is not reading from field elevation. That is the altitude above mean sea level. MSL. The only altimeter that reads AGL is a radar altimeter.

Yes, but only right above the airfield. If the airfield is for example in a valley, this is not true anymore anywhere else.

 

AGL as such is always true for any spot as it is measured constantly (i.e. radar).

Which then leads me to question why a commercial approach plate would use altitudes that are only valid right above the airfield. QFE would no longer be valid outside of the airfield if it were in a valley, like your example, and therefore not valid over terrain. It makes no sense. In the charts I've seen terrain is presented in MSL, which would require QNH for clearance.

Once again, you are confused. QNH is not reading from field elevation.

No sir, you are confused. When you set altimeter to QNH the altimeter will read field elevation MSL when on the ground.

http://en.wikipedia.org/wiki/QNH:

An airfield QNH will cause the altimeter to show airfield altitude, that is, the altitude of the centre point of the main runway above sea level on landing, irrespective of the temperature.

Which then leads me to question why a commercial approach plate would use an altitude that is only valid right above the airfield. It makes no sense. In the charts I've seen terrain is presented in MSL, which would require QNH for clearance.

 

 

 

No sir, you are confused. When you set altimeter to QNH the altimeter will read field elevation MSL when on the ground.

 

http://en.wikipedia.org/wiki/QNH:

Where did I say approach plate? I didn't say approach plate. I said approach PROFILE. I'm done arguing. If you really want to understand something and not be ignorant you should do your research first. Especially coming from someone who has over 5,000 hrs flying real jets, I should know what I'm talking about. I tried to help. I gave my input and it is correct. Go study.

Once again, you are confused. QNH is not reading from field elevation. That is the altitude above mean sea level. MSL. The only altimeter that reads AGL is a radar altimeter.

QNH is one of the many Q codes. It is defined as, "barometric pressure adjusted to sea level."

Copy and paste from your link above. Thanks for verifying I am correct.

You didn't verify squat, you didn't even read the entire article and only read the first two sentences. You're just putting up a front to avoid admitting that you got your Q-codes confused. Again, same article, copy-paste:

An airfield QNH will cause the altimeter to show airfield altitude, that is, the altitude of the centre point of the main runway above sea level on landing, irrespective of the temperature.

Bolded, for your convenience. This verifies that I am correct in that setting altimeter to QNH will read airfield elevation on the ground.

By the way, the approach profile you speak of is on the approach plate, and altitudes are given in MSL. They are not "based off QFE." Wrong again.

I still don't understand why QFE would be used by a commercial airliner in the US when all classes of airspace (except Class G, obviously, since it's uncontrolled) are defined in MSL, transition altitude is defined in MSL, approach plates/profiles are defined in MSL, and METAR/ATIS gives sea-level pressure a.k.a QNH.

Altimeter confusion...

Dude once again. I did not mention anything about an approach plate. You obviously don't know what profile is. Become an airline pilot then you can apologize later.

Okay. Let me explain this hypothetically. You set QNH while at an airport at KDFW and the altimeter will read 608'. Why? Because the elevation is 608' ABOVE sea level. It doesn't read as zero. Right? So, for it to say zero, we set it to QFE.

Now let's change airports. Set QNH at KASE, Aspen Colorado. Lots of mountains. On the runway it will say the elevation ABOVE SEA LEVEL. Not zero. To do that set QFE. Now let's say we are on approach at KASE and we want to know how high we are above airport elevation, we set QFE. It will NOT read AGL. Why? Because Red Table or whatever mountain it's called is right beneath us. Our AGL will be 1000', but our altimeter set to QFE will read 4000'-5000'.

If you don't understand this now, I have lost hope.

Edit: double negative

Dude once again. I didn't not mention anything about an approach plate. You obviously don't know what profile is. Become an airline pilot then you can apologize later.

 

Okay. Let me explain this hypothetically. You set QNH while at an airport at KDFW and the altimeter will read 608'. Why? Because the elevation is 608' ABOVE sea level. It doesn't read as zero. Right? So, for it to say zero, we set it to QFE.

 

Now let's change airports. Set QNH at KASE, Aspen Colorado. Lots of mountains. On the runway it will say the elevation ABOVE SEA LEVEL. Not zero. To do that set QFE. Now let's say we are on approach at KASE and we want to know how high we are above airport elevation, we set QFE. It will NOT read AGL. Why? Because Red Table or whatever mountain it's called is right beneath us. Our AGL will be 1000', but our altimeter set to QFE will read 4000'-5000'.

 

If you don't understand this now, I have lost hope.

I understand that fully, but now you are backtracking. Earlier in the thread you said that QNH did not read altitude above sea level at the airfield and now you are.

What I don't understand is why use QFE when going to KASE when "Red Table or whatever mountain it's called" has its altitude charted in MSL and the airport elevation is also charted in MSL. Dial QNH, subtract airfield elevation from current altitude. Done. Or are you using QFE simply as a shortcut for that?

And again, the approach profile is on the approach plate. If you can prove me wrong with a picture, show me this separate "approach profile" because Google cannot find one. Google also found that American Airlines stopped using QFE "a few years" before 2003.

No I said QNH is not based or read on the field elevation it is read from Sea Level. That's why when you put in QNH it reads the ground elevation when on the ground.

Like I said when certain procedures or profiles dictate such use. From my very first post I mentioned AA uses QFE sometimes. Yes it can be used as a shortcut. Light bulb! You got it.

That would depend on where you're doing circuits. If at any decent sized airport inside CAS then you will be given a VFR circuit clearance not above an altitude. Altitude = QNH.

 

And to those who would suggest that a controller would happily have QFE and QNH traffic close to each other and would personally calculate the differences, sod that, way to much like hard work. A controller will tell you to fly at an altitude, hence QNH. You may ask for QFE and use it for your own purposes, but if you are instructed to fly at an altitude (which you will be in the UK) then it's up to you as the pilot to adhere to your clearance.

 

QFE may be used at uncontrolled GA aerodromes but it certainly has no place in the commercial world. The only real value of QFE is to make a circuit look pretty on the altimeter. Probably why the RAF still use it, they like pretty things, like medals and stuff ;)

The vast majority of GA airfields lay outside controlled airspace, so that's a poor example.

It's VFR or IFR traffic, not 'QFE' and 'QNH' . Biggin Hill, Manson, Lydd Southend and Shoreham are all outside controlled airspace but all have ATC; they also all accept IFR traffic. IFR traffic will typically fly straight in on an instrument approach while VFR traffic will fly the pattern on QFE and it all works very well. That you think different altimeter settings would caues a problem for anyone demonstrates a lack of practical understanding.

I understand that fully, but now you are backtracking. Earlier in the thread you said that QNH did not read altitude above sea level at the airfield and now you are.

 

What I don't understand is why use QFE when going to KASE when "Red Table or whatever mountain it's called" has its altitude charted in MSL and the airport elevation is also charted in MSL. Dial QNH, subtract airfield elevation from current altitude. Done. Or are you using QFE simply as a shortcut for that?

 

And again, the approach profile is on the approach plate. If you can prove me wrong with a picture, show me this separate "approach profile" because Google cannot find one. Google also found that American Airlines stopped using QFE "a few years" before 2003.

http://code7700.com/g450_go_around_missed_approach.html

This isn't a good example because it doesn't make reference to QFE but this is a profile. Not approach plate. It's for a Gulfstream 450 I believe. I'd like to make a copy from my manuals but I can get fired for that. The procedures, like I said, can be to extend flaps or gear or make a callout at various altitudes above the field or for company specific procedures. Hence, QFE is used. Like I said long before.

I see, we had an error in semantics. What you linked is a procedure. The approach profile I know is the IFR approach profile box in the lower portion of an approach plate/chart.

Back to that approach procedure, if the aircraft had a radar altimeter would you even need to mess with QFE?

Altimeter confusion...

It's a profile, man. In my American Eagle Airlines manual, that was certified by the FAA, it's tabulated "profiles". And there is a profile that almost looks exactly like that for that exact procedure. A go-around/missed approach for the pilot flying.

Like you said before, as a shortcut, it can be used. Or just do the mental math. 1,500MSL-500FE = 1,000 Above FE or 1,000' QFE

Edit: the pilot monitoring will have the more items related to QFE.