The Mil and their use of QFE
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P R
May I refer you back to my origional reply?
Your:
"Would it not be easier for pointy ended jockeys to learn about QNH Ops" comment was covered.
We do!!!!
As for the sarcstic bit that followed, I choose to refrain from comment since I'm in a good mood today. Chill - think gentle thoughts, then blast away at random
May I refer you back to my origional reply?
Your:
"Would it not be easier for pointy ended jockeys to learn about QNH Ops" comment was covered.
We do!!!!
As for the sarcstic bit that followed, I choose to refrain from comment since I'm in a good mood today. Chill - think gentle thoughts, then blast away at random
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Harrier 46
Shows how much flying you do outside the UK then. Say QFE to any non-UK European, or US pilot, and they'll look at you with a very quizzical expression.
The earth orbits the sun - not the other way round
Whowhenwhy
People in glass houses shouldn't throw stones (though I'm intrigued by the word 'unfortunately'). We do things by our book, you do it by yours - but who's book is right? And what is this attraction to to military of holding onto traffic until it's almost in someone else's overhead? I'm noticing that more and more these days. (sorry - off topic I know)
See my comment above. In the world of instrument flying you really don't care what the altimeter reads on landing. All you want to to know is:
a) MSA - Last time I looked spot heights were based on amsl, not some arbitrary airfield elevation. QNH is therefore more relevant than QFE when I'm working that out on a route
b) DA/MDA - after that you can see where you're going so you don't actually look at the altimeter. What it reads is therefore of no consequence. As an instrument go around will, in most cases, be based on QNH why would you want to complicate matters by transitioning from QFE to QNH in addition to the rest of the tasks that need to be carried out in a very short space of time in that scenario.
Still think the military is right and the rest of the world is wrong? I've not flown a QFE approach in the last 5-6 years - it's no hardship, believe me.
Rather than the mil changing why not the civilians? Having experienced using both, QFE is (as said previously) much simpler. And sat at the runway threshold showing no altitude is (at least to me) logical.
The earth orbits the sun - not the other way round
Whowhenwhy
Unfortunately, mil controllers tend to apply everything as per the book, whereas civil controllers sometimes tend to do otherwise. Specifically, ATSOCAS! (But lets not get into that again)
(though I'm intrigued by the word 'unfortunately'). We do things by our book, you do it by yours - but who's book is right? And what is this attraction to to military of holding onto traffic until it's almost in someone else's overhead? I'm noticing that more and more these days. (sorry - off topic I know)
As far as QFE/QNH is concerned, surely it's better to fly on a pressure setting that gives you a zero reading when you're on the runway?
a) MSA - Last time I looked spot heights were based on amsl, not some arbitrary airfield elevation. QNH is therefore more relevant than QFE when I'm working that out on a route
b) DA/MDA - after that you can see where you're going so you don't actually look at the altimeter. What it reads is therefore of no consequence. As an instrument go around will, in most cases, be based on QNH why would you want to complicate matters by transitioning from QFE to QNH in addition to the rest of the tasks that need to be carried out in a very short space of time in that scenario.
Still think the military is right and the rest of the world is wrong? I've not flown a QFE approach in the last 5-6 years - it's no hardship, believe me.
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"Try explaining QNH to the man in the street"
See that hill over there - the map here says that it is 2500ft above sea level. When the altimeter reads 2500 or less with the sea level pressure set we will hit that hill.
See that airfield over there - the map here says that it is 625ft above sea level. When the altimeter reads 625ft we will hit that runway.
Most common cause of initial IR rating test failure is pilots failing to reset QNH in the missed approach having made an approach using QFE - UK CAA.
It's an altimeter not a heightameter!
Regards,
DFC
See that hill over there - the map here says that it is 2500ft above sea level. When the altimeter reads 2500 or less with the sea level pressure set we will hit that hill.
See that airfield over there - the map here says that it is 625ft above sea level. When the altimeter reads 625ft we will hit that runway.
Most common cause of initial IR rating test failure is pilots failing to reset QNH in the missed approach having made an approach using QFE - UK CAA.
It's an altimeter not a heightameter!
Regards,
DFC
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Doh!
OK Mr man-in-the -street:
See that runway, in fact any runway, anywhere any time? Well with QFE set - when the altimeter reads zero you will be landing on it.
See that hill just over there? The nice man / lady in ATC or the little book of Approach Plates I carry that tells me how to get to the runway also tells me a height not to fly below so that I can be sure to miss that hill.
When we fly away from the airfield but stay quite near the ground I will set the QNH on the altimeter so that I know how high I am in relation to the sea level cos that is the datum height my maps use to show me how high the hills are. But just like the QFE thingy - we'll need to change it every now and then cos the pressure over the country changes you know.
And if we go high, no matter where we are we set SPS so that we can all miss one another.
Easy isn't it? - no matter where I go or how busy I am I know that the runway = zero on the altimeter with the QFE set and there are only the other two thingys to remember when you arn't quite as busy.
Now would you like to be patronised about any thing else?
OK Mr man-in-the -street:
See that runway, in fact any runway, anywhere any time? Well with QFE set - when the altimeter reads zero you will be landing on it.
See that hill just over there? The nice man / lady in ATC or the little book of Approach Plates I carry that tells me how to get to the runway also tells me a height not to fly below so that I can be sure to miss that hill.
When we fly away from the airfield but stay quite near the ground I will set the QNH on the altimeter so that I know how high I am in relation to the sea level cos that is the datum height my maps use to show me how high the hills are. But just like the QFE thingy - we'll need to change it every now and then cos the pressure over the country changes you know.
And if we go high, no matter where we are we set SPS so that we can all miss one another.
Easy isn't it? - no matter where I go or how busy I am I know that the runway = zero on the altimeter with the QFE set and there are only the other two thingys to remember when you arn't quite as busy.
Now would you like to be patronised about any thing else?
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There's always one that falls into the trap
.
Not so hypothetical question. If the QNH was the same as the standard (1013) what would the QFE be at:
a) Las Vegas McCarran (2181 ft amsl)?
b) Big Bear City (6748 ft amsl)?
There are others around the world - they're just two that I have the figures in my head for.
As an addition to the question - can you physically set that QFE on your altimeter?
All the plates I've used show MSA, not MSH, but happy to be corrected if the Mil produce the latter.
in fact any runway, anywhere any time? Well with QFE set - when the altimeter reads zero you will be landing on it.
Not so hypothetical question. If the QNH was the same as the standard (1013) what would the QFE be at:
a) Las Vegas McCarran (2181 ft amsl)?
b) Big Bear City (6748 ft amsl)?
There are others around the world - they're just two that I have the figures in my head for.
As an addition to the question - can you physically set that QFE on your altimeter?
the little book of Approach Plates I carry that tells me how to get to the runway also tells me a height not to fly below so that I can be sure to miss that hill.
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<<Not so hypothetical question. If the QNH was the same as the standard (1013) what would the QFE be at:
a) Las Vegas McCarran (2181 ft amsl)?
b) Big Bear City (6748 ft amsl)?>>
Sounds like a QNE question to me..........
a) Las Vegas McCarran (2181 ft amsl)?
b) Big Bear City (6748 ft amsl)?>>
Sounds like a QNE question to me..........
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If I can't set the QFE (altimeter mb sub-scale limited I presume) I'll set QNH and get on with it! - just like I did in both Big Bear and McCarran. I am both flexible and a realist. It ain't a pi**ing contest, it's a forum. I can & do work both procedures - I just prefer QFE.
Your right about the MSA thing - for that I take off my shoes and socks and do the difficult sums before the approach (and set QNH on the other altimeter). Its only a trap if you don't know the way out
Now the Russian thingy was a real bag of metered worms
We could keep this going for weeks!
It ain't a pi**ing contest, it's a forum. I can & do work both procedures - I just prefer QFE. Your right about the MSA thing - for that I take off my shoes and socks and do the difficult sums before the approach (and set QNH on the other altimeter). Its only a trap if you don't know the way out
Now the Russian thingy was a real bag of metered wormsWe could keep this going for weeks!
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Ahhhh QNE!
Have actually used it... once. Extremely low pressure up in Aberdeen (942mb?).
A further question. The RAF isn't the only air force to drive fast pointy things around the sky. What do other air arms use? How many use QFE (or would have any idea what you are talking about)?
Rgds BEX
Have actually used it... once. Extremely low pressure up in Aberdeen (942mb?).
A further question. The RAF isn't the only air force to drive fast pointy things around the sky. What do other air arms use? How many use QFE (or would have any idea what you are talking about)?
Rgds BEX
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How many of us (in the UK) fly around the visual cct with QNH set?
Similarly, how many of us transit underneath a TMA with the local airfield's QFE set?
How many of us have tried to set the Kabul (6870ft AMSL) QFE?
Why do we have a mixed transition altitude in the UK (mostly 3000ft but 6000ft under a number of TMAs)?
What does it matter as long as everyone knows what datum they are flying relative to and the controllers can do their maths when mixing 2 or more pressure settings?
Personally, I think the mixed use of pressure settings can be a recipe for disaster. However, surely we can just bite the bullet and get on with it.
PS. How many feet equate to one millibar at 35000ft when the temp is ISA -10deg Celcius. Anyone who uses the 30ft rule will be in for a shock.
Similarly, how many of us transit underneath a TMA with the local airfield's QFE set?
How many of us have tried to set the Kabul (6870ft AMSL) QFE?
Why do we have a mixed transition altitude in the UK (mostly 3000ft but 6000ft under a number of TMAs)?
What does it matter as long as everyone knows what datum they are flying relative to and the controllers can do their maths when mixing 2 or more pressure settings?
Personally, I think the mixed use of pressure settings can be a recipe for disaster. However, surely we can just bite the bullet and get on with it.
PS. How many feet equate to one millibar at 35000ft when the temp is ISA -10deg Celcius. Anyone who uses the 30ft rule will be in for a shock.
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I think you'll find also that SID's use flight levels and altitudes for the initial climbing levels. If there was a high transition altitude then in the initial climb from take off through the TA would involve three changes of pressure settings, which would increase workload.
I assume that the mil use QFE because they like it and the controllers can provide some separation. Don't forget that anyone bashing circuits at a civilian airfield will use QFE.
If the mil want to transit civil CAS then they will be instructed to fly QNH for separation purposes. I find it far easier, with less workload to use QNH, 1013.25 and airfield elevation.
I assume that the mil use QFE because they like it and the controllers can provide some separation. Don't forget that anyone bashing circuits at a civilian airfield will use QFE.
If the mil want to transit civil CAS then they will be instructed to fly QNH for separation purposes. I find it far easier, with less workload to use QNH, 1013.25 and airfield elevation.
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If you are flying at 35000ft then you should be flying at a flight level of 35 with all the other a/c in the area flying on 1013.25. minus 10 degrees is irrelevent. I agree with all using the same datum, however radar cannot determine the datum a/c are flying to. It is easier for the controller to have all the a/c flying on the same pressure setting to ensure separation.
Please keep safety first.
Please keep safety first.
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<<I think the mixed use of pressure settings can be a recipe for disaster. However, surely we can just bite the bullet and get on with it.>>
Hopefully not the attitude of professional controllers! If something is that dangerous it needs fixing.
ILS 119.5 wrote: "If you are flying at 35000ft then you should be flying at a flight level of 35"
I think not, but I (think I) know what he means.
Hopefully not the attitude of professional controllers! If something is that dangerous it needs fixing.
ILS 119.5 wrote: "If you are flying at 35000ft then you should be flying at a flight level of 35"
I think not, but I (think I) know what he means.
ILS 119.5. WB's SATCO is alluding to other airspace users who use a regional pressure setting to maneouvre up to say 45 000'. In this instance, when coordinating with said users, finding that the 30' per millibar assumption is wrong has come as quite a shock and no-one is quite sure exactly what to do about it.
As far as the QFE/QNH issue is concerned, I think people are starting to get a little confused. We use QFE in the instrument and visual circuits and for aircraft flying close to, or through, these patterns. Outside this, ac should be flying on a RPS below the TA and the SAS above.
Chilli, aside from the differences of necessity due to mil vs cvi ops, there aren't that many key differences between "your" book and "ours." They would all have come from the same root document in the dark mists of time. But why would you change from QFE to QNH on a missed approach? Maybe yes if you were flying away from the airfield after the approach, staying below the TA, but certainly not if you were going back around for another go.
As far as the QFE/QNH issue is concerned, I think people are starting to get a little confused. We use QFE in the instrument and visual circuits and for aircraft flying close to, or through, these patterns. Outside this, ac should be flying on a RPS below the TA and the SAS above.
Chilli, aside from the differences of necessity due to mil vs cvi ops, there aren't that many key differences between "your" book and "ours." They would all have come from the same root document in the dark mists of time. But why would you change from QFE to QNH on a missed approach? Maybe yes if you were flying away from the airfield after the approach, staying below the TA, but certainly not if you were going back around for another go.
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My 35000 ft comment was aimed at some elements of the mil who fly at this sort of level on the RPS!!
Regarding my "biting the bullet" statement, maybe it was not the best choice of words. What I meant to say was that there may be perfectly valid reasons for operators to fly on different pressures. We should be able to manage their expectations and deal with the issues.
Regarding my "biting the bullet" statement, maybe it was not the best choice of words. What I meant to say was that there may be perfectly valid reasons for operators to fly on different pressures. We should be able to manage their expectations and deal with the issues.
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But why would you change from QFE to QNH on a missed approach?
2) After a missed approach you'll often have briefed the plan that you may be going somewhere else, at MSA - hence QNH required
3) All missed approaches are required to be "terrain safe" (obviously). Approach plates show MSA, not MSH (as stated before) therefore datum required is QNH
DFC's post is quite correct when he points out the single biggest fail on Instrument Rating tests flown on QFE is failing to reset QNH on the missed approach - hence flying the approach QNH takes out that possibility.
Re (1 & 3) above it's worth remembering of course that, unlike the military, not all airfields with IAP's have radar. Therefore an RVA chart is not applicable from which a controller can put you on QFE and keep you 'terrain safe' according to his chart / video map. Terrain clearance is still the responsibility of the pilot fully in that scenario hence the use of QNH as the 'safe' datum
Last edited by Chilli Monster; 30th Jan 2005 at 09:17.
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It is nonsense and, in my view dangerously confusing, to use QFE for anything other than final approach. Indeed, most civil operators long since ceased to use it even for that.
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HD
Yeah sorry FL350, too used to doing approach. Have not done area since 85.
Also for any a/c to fly up to 45000' why use a regional pressure setting? I think that the rules of the air state that above a certain level all a/c must fly on 1013.25. Please correct me if I am wrong.
Yeah sorry FL350, too used to doing approach. Have not done area since 85.
Also for any a/c to fly up to 45000' why use a regional pressure setting? I think that the rules of the air state that above a certain level all a/c must fly on 1013.25. Please correct me if I am wrong.
Unless under the control of ATC, HM Ships or ASACS!!!!! Say, if they were in the block surface to 45 000'? That's the problem!
Chilli. Good points. Some down to civ/mil differences and of course I am viewing QFE/QNH from a purely mil point of view. I can certainly see the benefits from a human factors point of view, but still like the idea of seeing 0 when I'm on the runway. Maybe I'm just old and resistant to change?? Unlike my NATS brethren who have their destinations and who are all far from being resistant to change (sorry going off thread now!).
Chilli. Good points. Some down to civ/mil differences and of course I am viewing QFE/QNH from a purely mil point of view. I can certainly see the benefits from a human factors point of view, but still like the idea of seeing 0 when I'm on the runway. Maybe I'm just old and resistant to change?? Unlike my NATS brethren who have their destinations and who are all far from being resistant to change (sorry going off thread now!).