Why do the RAF still use QFE?

[WX Man]

Just pondering the thought. Why do RAF pilots still use QFE? As a civvy pilot, I use QNH all the time, everywhere... except RAF bases. Just wondering why.

[Pontius Navigator]

We went round this buoy many times and in 1990 Lady Lucinda Buck's lover decreed that we went to QNH. At great expense, and contrary to all advice at the time, we went to QNH. After the Daily Mirror expose the first thing that was done was to revert at great expense to QFE.

The RAF does use QNH at many airfields such as Kandahar and Nairobi.

[Fast Pussy]

Dah!! 'Cos it tells you how high you are above the point you intend to land at??? Without having to do any mental gymnastics???????

Go to any shop and watch today's teenager giving you change - do they do mental arithmetic, or do they look at the screen to decide how much money to give back to you?? And who provides today's pilots?? Mr QNH, or Mr Let's Keep It Simple???

And anyway - the Americans work on QNH, so that's as good a reason as any for using QFE!!

:yuk:

[scarecrow450]

stops you flying into the ground ?

[bast0n]

No brainer - most people would like to see zero on the altimeter as the wheels touch the ground not some mystical height you have to think about............:ok:

KISS:)

[Sierra Hotel]

From what I was told, only this week, commercial pilots use QNH for procedural approaches, whilst the military are on QFE. In GA pilots may opt for either.

[HEATHROW DIRECTOR]

<<but in Commercial Aviation they use QFE for instrument approaches. (I may be out of date on this).>>

Unless things have changed since I retired 7 years ago, just about all airlines use QNH. The last ones to use QFE thar I recall were Aer Lingus and one or two east European companies, but they had changed by the time I left. Someone more up-to-date will no doubt comment.

[Pontius Navigator]

HD, I will accept that as my info pre-dates your retirement.

That Sir Peter temporarily got the RAF to use QNH and the RAF then rebelled is not in doubt. Perhaps one of the few cases where we actually changed back.

[Paul Chocks]

The only real value of QFE, that I can see, is to make a circuit look pretty on the altimeter. Downwind at 1000' and final at 500' for example.

I don't ever recall looking at the altimeter as I touchdown (if you really needed to know your ht a rad-alt would be better)

On instrument approach it matters not, as long as you know which datum is set and then fly to the appropriate minima.

QNH (or RPS) much better for terrain clearance and stopping you from entering controller airspace from below.

QFE may help for elementary/basic cct trg, but for anything else, I'd go with QNH.

[Tankertrashnav]

We used QFE at Lands End (yes it is a civvy airport) till our club folded there this year. Or was that just to make it easy for us studes, as implied by Paul Chocks?

[XL319]

I think the rules changed last year didn't they? All aircraft preparing for take off are given QFE unless QNH is requested.

[octavian]

The only organisation in the UK that would appear to routinely use QFE is the RAF (plus, I assume, the RN and AAC?), although I don't know what the formerly shiny fleet at Brize and the Truckies at Lyneham use.

All datums at significant civil aerodromes are based on QNH and I know of no airline or AOC operator (UK or otherwise) which uses anything other than QNH for visual or instrument approach work. All the charts published (Jepp, Aerad etc) use QNH with heights referred to threshold/aerodrome elevation in brackets (presumably for the RAF). For Nairobi and other similarly elevated aerodromes, I seem to recall that QNE was the most used practice given the limitations of altimeters.

Given that, in a relatively short flight outside controlled airspace, a relatively inexperienced or student pilot, not to mention those of greater experience, can be instructed to fly on 3 or more potentially widely spaced pressure settings QNH, Regional Pressure Setting, QFE, Standard (1013.2) if feeling brave, perhaps another RPS and another aerodrome QNH, the potential for confusion and misreading/mis-setting altimeters with all these changes of setting is, I would suggest, greatly increased.

In these days of constantly updated information are RPS really relevant? These would appear to date from the days of the Shackleton and Dakota when pilots were out of communication for prolonged periods and needed a FORECAST RPS for the areas in which they were operating.

Is QFE really necessary? Even for a Surveillance Radar Approach the controller passing an advisory altitude based on QNH is giving the pilot a figure to which he/she may adjust rate of descent. At Decision Altitude/Minimum Descent Altitude the pilot will take an appropriate action on the basis of that altitude. Seeing zero on the altimeter at the threshold is an irrelevance, as at the threshold it may need to read 50ft or so.

Let's just have QNH and Standard and be done with it. And whilst we're about it let's have a standard transition altitude. Howzabout 10,000ft. So that'll knock it down to a very few pressure setting changes for those unpressurised aircraft operating outside CAS and below 10,000ft.

Standing by for incomers..........

[farsouth]

With you all the way Octavian, thanks for saving me writing similar

[WX Man]

Interesting responses (and so many, in so short a time!). Seems to me that the arguments for using QFE are:

- to fly a circuit you don't have to add 1000ft to the aerodrome elevation
- to fly an approach you don't have to get into the mindset that the hard stuff isn't going to be where the height pointy thing says "0".

Given that I'm no mental arithmetic genius and that I can still do both of the above, I'm guessing that the guys and girls who are far brighter than I and lucky enough to be flying some of the finest flying machinery known to mankind can probably also do the same.

There is only one occasion where I can think that having QFE set is actually more sensible than having QNH, and that is when you're flying a PAR. Other than that, I see no reason why everyone shouldn't have QNH set all the time (when they're below transition).

FWIW, I'm totally with Octavian. Simplify the whole darn shebang, so that everyone in uncontrolled airspace is flying on the most accurate QNH available (RPS? WTF?). From the geezer in the microlight at a private strip, to the guy in the Typhoon transiting to the exercise areas, to airliners entering the shark infested custard between airway and (for instance) Teesside/Plymouth/Doncaster's zones. Everyone uses QNH below 10,000ft: *highly* sensible. In fact: let's have a Europe-wide altimeter policy, where everyone below the highest terrain (Mont Blanc, 15,781ft) uses QNH: round it up and let's call it 18,000ft... which, funnily enough, would bring Europe into line with the USA.

So, Octavian, I'm with you on this one. I wonder how many other folks are?

[walter kennedy]

What about an LZ, say in an op area, with no ATC? Throw in marginal conditions.
Which would be best?

[bast0n]

Walter

Ha Ha - you have said it matey!!:ok:

[Roland Pulfrew]

WX Man

I'm not. QFE is only use in the circuit area/instrument approack. When the wizzy FJ is zipping around at low level it does use QNH, in this case the regional pressure setting. I for one prefer to land at 0 feet, and when I am landing somewhere else a lot higher I will treat it with the caution that it deserves.

Why should the RAF change? It works for us, if you don't like it, don't fly into RAF airfields.:hmm:

would bring Europe into line with the USA.


And that surely is the best argument for not doing it!;)

[bowly]

Roland makes a valid point. It is much easier (and safer) to always see the same numbers whichever airfield you are using. Your 400' point is always your 400' point and not some random figure you've calculated after 8 hours sausage side! I'm with the KISS brigade.

[Tankertrashnav]

Slightly off thread but do they still use inches over the other side of the pond? I seem to remember that when the RAF bought the Phantom they spent about a trillion pounds fitting them with Rolls Royce engines and various other mods but balked at twopence halfpenny per aircraft to alter the altimeter scales to millibars, requiring every ATC for years to come to pass altimeter settings to Phantoms in inches. Great fun in tankers (using millibars) with a pair of them in tow.

[chiglet]

Octavian,
Simple. Just put in a "Request for Change"......:E
We all know what will happen. A "Hissy Fit" from Ops, then quietly filed in File 13 [the LATU box]

[Gargleblaster]

Odd. All over the world, civil and military pilots takeoff and land on QNH. Private as well as professional pilots. In all kinds of weather. So is using QNH dangerous ?

[mad_jock]

As someone who used to fly very regualrly into RAF bases as a civ flight.

It really doesn't matter a toss.

QFE/QNH all RAF pilots can operate on QNH and all civi pilots can operate on QFE its not a bloody problem.

If it means that the boy's in theater can get even 1 minute extra on the phone or one of the most piddly little bits of kit which makes life more comfy don't change a bloody thing.

The very small amount of ball ache involved is worth it compared to spending a sodding fortune changing everything.

I do wonder how many of the civi pilots with very strong views on the subject have had to operate day in and day out using the system. It really doesn't matter.

[dash2]

Well said. It really isn't that important so why change it...and it works.

[Wholigan]

I have - like many of you - used both as a military pilot.

In the UK where even the highest airfields are probably less than 600 feet above MSL, you probably won't mind winding the altimeter from 1013 to 993mb (at worst).

However, if you wanted to fly into - say - Black Rock airfield in the States, you might not enjoy the wrist and finger ache you would get changing from 1013 to 798mb.

Then just imagine going into San Rafael Airport in Peru, where you would need to set 532mb. Anybody know an altimeter that goes that low???

Horses for courses methinks.

[newt]

Why do RAF pilots use QFE?

Well yeh! but no but yeh! because they can!

Simples!

:ugh:

[Neptunus Rex]

Quite right Wholigan.

There is another, easier option for high level airfields, request QNE. QNE is your altimeter reading with 1013.2 set. Thus ATC would give you the number of feet you would see on your altimeter on the ground at the airfield datum with 1013.2 set in your subscale. I had to use that at Entebbe when the QNH was outside the range of my altimeter.

Neppie
:eek:

[Juan Tugoh]

QFE or QNH both make some sort of sense - either Oft or the airfield elevation on touchdown. QNE gives you reference to neither very well and is a pointless throwback to the era of limited mechanical altimeters.

I suppose it makes sense if you are still operating really antique equipment AND operating out of Bogota. QFE makes more sense for a largely UK based operator but makes little sense to a largely worldwide operator. If the likes of BA and Virgin and the rest of the airline world use QNH it is not for a whim. Terrain awareness and IAS/TAS issues at hot and high airfields tend to push you towards QNH for safety reasons. QFE is fine for a parochial, inwards looking, UK centric operation.

[anita gofradump]

Is this one of those Pprune threads that gets revisited when there's not much else to discuss? Seems to read that way.

At great risk of repeating previous posters, it really is a case of being able to use either, as is appropriate for the situation. I remember a lecture about flexibilty in air ops...................

[BEagle]

I always thought that QNH with ApproacH and QFE with TowEr was the best compromise.

I was instructing at a UAS when we changed from QFE to QNH. Not too difficult until one (very good) student was given an EFATO. She called that she was above the turnback min height and started a turnback only to have the QFI take control and climb away. Brought up on QFE she'd reverted to habit - only the aerodrome elevation was nearly 400 ft and she was much lower than she thought.

The QNH experiment didn't last that long - but it wasn't Learning Command who insisted we went back to QFE, it was the fast-jet pointy-heads.

Why does the RAF use QFE? For the same reason mutts lick their nuts - because they can!

[Pontius Navigator]

What about an LZ, say in an op area, with no ATC? Throw in marginal conditions.
Which would be best?

Walter, you didn't offer an answer and no one else has.

RAD ALT.

If there is no one there to measure the pressure then you have to set your own.

If the LZ is on high terrain in a plain then again you need visual or rad alt.

[bast0n]

Pontious

Walter, you didn't offer an answer and no one else has.

Well I will!

Picture flying in a helicopter into a LZ at night in the mountains of Norway to an approach aid consisting of five torches for the use of laid by the MAOT. On the approach the Rad Alt is useless as it is reading under the aircraft and wizzing up and down as you pass over the terrain. What would you like to see on your Bar Alt as you approach the T?

I like to see it winding down to zero not some height above sea level that I have to remember. It's hard enough flying the aircraft especially if the wind is up your chuff and bouncy, it's snowing and you are not allowed to use landing lights. Oh - and you are about to get whiteout in the dark!!

Airfields are a totally different ball game for people with less flying ability!:)

Ducking and running now.................:ok:

[kitwe]

[B]Tankertrashnav[B]

I started flying in Phantoms in 1970. All of the aircraft that I subsequently flew in (including some of the prototypes) had altimeters calibrated in millibars.

[Pontius Navigator]

bast0n, fair dink, except you need a guy on the ground with an anemometer. How do the SAR crews operate?

[Bertie Thruster]

SAR, overwater; set Baralt to Radalt.

[bast0n]

Pontious

How do the SAR crews operate?

Very carefully! :ok:

They also have the ability to use their landing and floodlights and nowadays have NVG and probably FLIR for all I know. They also tend to operate in an area that they get to know very well.

In my days in SAR, Whirlwind and Wessex we were even more careful/stupid!:)

PS. you need a guy on the ground with an anemometer
I think you meant altimeter?

[Pontius Navigator]

PS.
I think you meant altimeter?

Doh! too early, too much vin, I meant barometer.

PS, we did the same, set altimeter to rad alt on the Nimrod so effectively we were on local QNH in an area or Force QNH is operating with other forces.

[bast0n]

Pontious

I like the idea of a barometer - sitting there in the cold with this big mahogany banjo shaped thing - tapping the glass and watching the needle jerk to Fair!!:ok:

[Pontius Navigator]

and reading off the arrow pointing to inches. Actually mine say 1007.2 towards Fair.

To be fair it is cool and sunny.

I think we are on the same hill - VFR is best.

[teeteringhead]

And of course rotary radalts have been known to tell you how far above the underslung load you are....:eek:

[The Exile]

P3 - there's no explanation for the use of QFE under those circumstances.

We (I'm a controller) should be expected to be able to work out the difference between RPS/SAS and QFE without being so lazy as to stick everything on one pressure. The only thing I can think of at that kind of distance was proximity to the unit's terrain safe level, which is based on QFE. Still no excuse though. Unless it's a local procedure of some kind, I can't speak for every unit of course. If anything it's easier to have non overhead transiting traffic on RPS/SAS because everything out and about would be using that pressure rather than a specific unit's QFE anyway. Circuit traffic and inbound traffic - QFE. Everything else - be flexible, from my point of view.

[bast0n]

Teeterer

And of course rotary radalts have been known to tell you how far above the underslung load you are....

and the Wessex had the final low flying warning when you noticed the main wheel spinning furiously...........................:ok:

[anotherthing]

Baston

PABs (Precision Aneroid Barometers) are in every military tower I've ever worked at, though I left the mil in 2001.

They are about 10 inches across by 6 inches deep and very transportable... no need for a wooden banjo shaped object with glass!!

[bast0n]

Anotherthing

PABs (Precision Aneroid Barometers) are in every military tower I've ever worked at, though I left the mil in 2001.

Oh I am disappointed! No mahogany?

I am a bit biased against people who work in Control Towers as two of them nearly killed me! See threads on Mid Airs etc.......................:ok:

To get back to QFE/QNH - they both have their place properly applied by intelligent operators.

[Green Flash]

The good old PAB's are being replaced by a slightly more whizzier Vaisala jobby (http://www.vaisala.com/files/PTB220%20Brochure%20in%20English.pdf)

[A and C]

As said above the British forces are very much in the minority using QFE however some parts of the opperation are very high workload such as IF approaches in a fast jet or SH. In these conditions I can see QFE being a distinct advantage, the rest of the airforce, army & navy follows the just to keep SOP at military airfields.

This may have to change as more modern aircraft come into service as QFE may well not be compatable with the aircraft systems. For this reason you cant use QFE on the Boeing 737NG as setting QFE feeds errors into the EGPWS.

[Downwind.Maddl-Land]

Well, I’m in for 2 penny-worth on this one:

I was an active controller (well, a SATCO anyway) during the QFE to QNH back to QFE debacle. The iteration that everyone seems to have forgotten about was that there was a period of ‘QNH for initial and intermediate approach’ and ‘QFE for the instrument final and circuit flying’, which – at that time – replicated civvie practise to a greater or lesser extent; I had to listen to Heathrow Director (the position, not the individual on these boards!) for many hrs responding to ‘localiser established’ with “x miles, QFE is XYZ millibars, contact tower, 118.2” - especially during CAT III operations.

From an ATC point of view the use of QNH simplified coordination greatly with the 2 very adjacent USAF units whose patterns integrated very closely with ours, and the scope for applying the QFE/QNH corrections in the wrong sense was obviated at a stroke; much ‘tidier’, simpler and therefore safer. Coordination with adjacent LARS units became a piece of cake and very quickly Airfield QNH (as opposed to RPS) became the usual datum for aircraft in transit below the transition altitude, which also helped with observance of the ‘set an airfield QNH when below or adjacent to a TMA’ rule.

However, even we ATCOs understood the desire of 'fast-jet' crews pointing towards the ground in East Anglian fog on a PAR or ILS to relate to their height above the threshold elevation – I’d want to do the same! Therefore, I always thought that the ‘halfway house’ was the most logical solution. However, the 2-winged master race didn’t! It was so obvious that a ‘meal’ was going to be made out of the new requirement to re-set the altimeter to QFE after establishing on the final approach track. This was so readily anticipated that I briefed my troops specifically to be circumspect on when to effect the change.

Perhaps the following undercurrents also mitigated against the policy:

a. The halfway house was perceived as a compromise – and who likes a compromise? Compromise goes against the Military ethic of ‘all or nothing’.

b. ‘Blood’ had been sensed when QFE was re-introduced for final approach – therefore, “a couple of CONDOR incident reports of mis-setting the QFE (despite the PAR Controller’s read-back check!), should see the status quo restored, boys! One last effort and victory will be ours!”

As an aside, I don’t recognise what P3 Bellows is on about at all; transit or LARS tracks on the QFE just makes for more mental gymnastics (with the resulting potential for error) when coordinating with other units, whereas RPS and the SAS provided a common datum within a locale; you just wouldn’t DO it as it makes life harder! Unless the rules have changed, the only time that QFE was mandated for use with transit traffic was for MATZ crossings, in order to coordinate with circuit and final approach traffic; otherwise it was RPS or 1013.2, below or above TL, respectively.

[C-N]

Well yeh! but no but yeh! because they can!
Simples!

Why does the RAF use QFE? For the same reason mutts lick their nuts - because they can!
exactly.


I think the RAF are in the dark ages regarding QFE

QFE is better for military pilots flying MIL aircrafts, as they have advanced equipment onboard and using only RAD ALT and are not using cheap pressure altimeters. again, just that simple.

Military stuff are always a step ahead, may it be aircrafts, software (they have military grade programming languages and MIL software standards), and onboard avionics equipments.

If all of us can just upgrade our pressure altimeters into rad alt then we can scrap this QNH thing altogether.

[Pontius Navigator]

Military stuff are always a step ahead,

That is what I thought when I joined 5 decades ago. No longer. We go for the cheapest now or the best 25 years late.

[Green Flash]

Use rad alts and we can get rid of pressure instruments - well, ok, I see your point. But what about those operators who wish to be so very stealthly - wouldn't the emisions from a rad alt give the game away?:confused:

(sudden blinding flash - what about GPS?)

[Occasional Aviator]

Some interesting perceptions here. Although I haven't done any military flying for three years or so, my recollection is that we used QNH for all instrument procedures, and QFE in the circuit or when it was necessary to deconflict with circuit traffic (leaving aside the MAOT on a mountain). QFE's just another usefult tool to heve in your golf bag - and I second the point about using it when you're learning to fly.

What I'm really a bit concerned about though, is that there seem to be a few people on here who don't know the difference between QNH and RPS....

[M609]

the desire of 'fast-jet' crews pointing towards the ground in East Anglian fog on a PAR or ILS to relate to their height above the threshold elevation

Funny how fast jet pilots of all other NATO countries manage just fine on QNH.

[Occasional Aviator]

Oh and C-N,

if you're advocating use of a radalt instead of a baralt for routing and instrument approaches I get the feeling you haven't really used a radalt. What radalt height would you put on the chart for the airways from Germany to Italy over the Alps for example?

Green Flash

Knowing the accuracy of the GPS height channel, I'd actually much rather that I and the guy coming the other way were deconflicted by cheap barometric instruments with known and bounded errors!

M609,

RAF pilots manage just fine using QNH for approaches too actually.

[WX Man]

My problem with QFE is one of traffic awareness. At the numerous mil airfields where there are adjacent civvy airfields (eg Brize/Oxford), having QNH set reduces a lot of the ballache about "if he's at 2000ft, what's he got set on his altimeter?". Clutch QFE is not a solution to this: the solution, as far as I'm concerned, is for everyone to use QNH and just realise that the ground isn't necessarily when the altimeter says 0ft.

The only exception to this is for a PAR. Even for ILSs, the rest of the world seem to manage very adequately with QNH approaches.

Flying on aerodrome QNH greatly reduces workload when it comes to coordination, situational awareness and can significantly help airspace infringements. All it requires is for people to realise that the ground isn't going to be at 0ft.

And, when one considers that most military pilot, when below 5000ft AGL can tell their height to +/-100ft just by looking at the ground features (isn't that part of the training?), I really can't understand why the RAF went back to using QFE after coming into line with the rest of the world.

[CarltonBrowne the FO]

Wholigan makes the best argument IMHO- QFE is a useful tool, but setting 763 mb for Addis requires a more expensive altimeter! As for QNE... it is giving me a headache sitting in a comfy chair with a cup of coffee, the thought of trying to use it while dodging thunderstorms, figuring out the circling approach (I've only ever flown it in the dark, in daylight it would probably scare me) makes me quite uncomfortable...

[10W]

If all of us can just upgrade our pressure altimeters into rad alt then we can scrap this QNH thing altogether.


Mmmm, so if I instruct one pilot to maintain 5000' on his radalt, and the other 6000' on his, are they going to enjoy the constant changing of the aircrafts attitude to follow the contours of the terrain beneath ?

And when the guy at 5000' is flying 1000' below them and triggers the radalt, are they going to do a zoom climb to ensure the 6000' based on the radalt is complied with ?

QNH is primarily used for terrain clearance, but there is also a secondary and important use in providing separation from other aircraft as part of an airspace system.

[Lightning Mate]

Er,

Excuse me Gentlemen.

How many radalts go above 2500 ft?

GPS?

That gives the "height" above the WGS84 ellipsoid......

[Two's in]

Military stuff are always a step ahead, may it be aircrafts, software (they have military grade programming languages and MIL software standards), and onboard avionics equipments.

...and there's me thinking this stuff was always being flogged by the lowest bidder or anyone who could spell "Warton".

[C-N]

get the feeling you haven't really used a radalt Haven't used one, honestly. Yet the word itself, radalt, sounds advanced and promising. Just confined to alts using aneroid at the moment.


Er,

Excuse me Gentlemen.

How many radalts go above 2500 ft?errm, you're right, not that advanced yet. looks like only a few reaches 10,000ft for civil use. yet i've heard AN/APN133 of C130 and AN/APN232 used by F16 and C141 are hi altitude radalts covering upto 50,000'.

[M609]

RAF pilots
Quote:
manage just fine
using QNH for approaches too actually.

I know, I controlled a few of them over the last few years, so I still cannot figure why the need to be different. (But then airspace policy, procedures, following international standards and UK MOD will not feature in the same sentence too often ;) )

[Wholigan]

Haven't used one, honestly. Yet the word itself, radalt, sounds advanced and promising.


Put simply, a radar altimeter measures the vertical distance between an aircraft and whatever ground happens to be below the aircraft at the time. When flying over the sea or a relatively flat terrain, it is a very useful tool. However, what it generally doesn't do is (for example) tell you that there is a fekk-off great big lump of granite just in front of you that is somewhat higher than the height you happen to be right now. Although you can partially get round that problem, it still doesn't solve how you can try to maintain a constant altitude (above MSL for example) using the radalt. Early radalts also had the problem that they only measured in a plane perpendicularly below the aircraft. You can guess what happened when you put bank on or changed attitude significantly.

Just imagine flying over markedly undulating terrain and ATC want you to maintain a specific altitude so they can arrange vertical separation between you and other aircraft in the vicinity. The radar altimeter indications are going to be rushing up and down like the drawers of a lady I once knew at RAF Valley, but even faster (if that were possible). Under these circumstances a basically barometric altimeter is going to indicate pretty much steady state altitude. (Yes I know that's not entirely true, but it's good enough to illustrate this situation and explain why you wouldn't want to use radalt.)

[BEagle]

Wholi', some of the modern toys are so clever that they can provide an altitude indication using methods less crude than GPS height.

Given the present position of the aircraft, a 3-D geographical database knows the elevation of the immediate terrain and and can apply the radalt (radio usually, not radar) indication to that to obtain an altitude amsl. The problem, though, is that whilst this is probably pretty accurate, altimeters work on ISA lapse rates etc as a standard, so everyone must 'speak the same language' - particularly in RVSM airspace. But this 3-D geo-database information can at least be used to set the CCWR scanner tilt to the optimum value, avoiding the need for barely-trained people-tube co-piglets to learn the art of weather radar control....:rolleyes:

The radar altimeter indications are going to be rushing up and down like the drawers of a lady I once knew at RAF Valley, but even faster (if that were possible).

One of the 'Sandymount set', perchance?

[Wholigan]

Aaaaah BEagle - - - I knew I was getting old and out of touch mate!!!

But I still had more fun than most folks can even dream of nowadays.



PS: you might be right in your guess! ;)

[newt]

What do you mean Wholigan? Fun, its supposed to be fun!! Just don't tell them that!

They might all want to do it!!

For me QFE works just as well as QNH! It just depends on how fast your going!!

The only rule is don't hit anything! Something we both know about!!

Off to the bar with flack jacket and a bottle of Grouse!!

PS Beagle

Was it Lockjaw or Pannel Beater?

[haltonapp]

At least when using QNH you know your height in relation to the the MSA, no mental gymnastics required. In the company I work for, we only set the DH on the rad alt when carrying out a CAT2 or CAT3 approach, because outside of these parameters, 100/50', the rad alt is not reliable because the terrain is not constantly level! You do get used to making all decisions with regard to altitude using airfields as diverse Amsterdam and Munich. It must only be the military that do not have a means of setting the pressure setting in inches or Mb on their altimeters. But then what do I know!

[C-N]

Occasional Aviator,

Knowing the accuracy of the GPS height channel

True, GPS is not accurate, that is, for civilian use. Because it was intentionally designed like that. Yet all military GPS signal use precision code which has a scary accuracy of just within 2ft.

[Blacksheep]

Beags, you forgot to add that the EGPWS, just like GPWS before it, also reads out the height above ground during final approach, just like a well trained PNH (or NHP, take your pick) :rolleyes:

Minimums, 50... 40... 30... 20... 10...

...and of course it also shows you all the lumpy bits ahead, if you decide to do a go-around and shouts at you like a real instructor if you don't pay attention. ;)

[BluntM8]

just like a well trained PNH (or NHP, take your pick)

In that case, I pick a navigator...:E


Love the comment below (page 2, IIRC) that the RAF does not understand the difference between QFE/QHN/RPS! How rude!

[spekesoftly]

the RAF does not understand the difference between QFE/QHN/RPS! How rude!QHN??? It does beg the question of understanding! ;)

[Wholigan]

15 - love to spekesoftly

"New balls please".

;)

[Lightning Mate]

Wholigan,

"The radar altimeter indications are going to be rushing up and down like the drawers of a lady I once knew at RAF Valley, but even faster (if that were possible)."

I knew her too....

[BEagle]

In the biblical sense?

Not to cast any doubt on the young lady's virtue or besmirch her character, but what became of Jane-Anne....?

[Lightning Mate]

Jane-Anne....?

....and her.....

[Wader2]

LM, the V-Force Radio Altimeter, a Mk 5 IIRC, went to 5000 feet. The Radar Altimeter, the Mk 6, went to 60,000 feet. It was a bit shabby below 500 feet.

The pair gave interesting and conflicting readings. The Mk 5 used to echo off the ground, the Mk 6 off the top of the tree canopy. Not good with 250 ft tall trees in the jungle.

[BEagle]

You didn't, did you LM.....:ooh:

[Arty Fufkin]

If learning command and FJ bases want to fly QFE to make the circuit easier that's up to them. Personaly, I think Brize and Lyneham should use QNH. A moden FMS's VNAV function is designed to work on QNH, everywhere else in the world uses QNH so why have your home base the only place where you do it differently.

The danger lies where Civ / Mil traffic is using different pressure settings in the same airspace (as can happen at Brize when a charter requests or is given a QNH approach.)
Or when you're a bit knackered and can't remember whether or not today's approach minma is the one in bold writing.
Plus, Sector saftey is an Altitude. I've heared it briefed hundreds of times but never seen anyone actualy apply a correction for airfield elevation when they declare that they're through S.ALT. climbing out with QFE set.

Do what the rest of the world does, they generaly have more experience!!

[Lightning Mate]

"You didn't, did you LM....."

Didn't you Beags? 'Sandymount set' (game and match most of the time).

[Occasional Aviator]

C-N

Yet all military GPS signal use precision code which has a scary accuracy of just within 2ft.

Well, yeees, but only when

a) it's available and not being jammed, and (more importantly)

b) it is in its normal operating parameters and not within one of the known or possible failure modes which could give you bounded or unbounded errors without indications of failure.....

[Roland Pulfrew]

I dont understand the request and i usually ignore it anyway.


Which is somewhat more worrying. You ask for a service (25 miles from the radar head) and they ask you to set the QFE (something I find very surprising) and you ignore the request!?!?! :ugh:

Do you know what else is in the area? Do you know what height they are descending to? Whether they are using QFE, which as the service is being given by an RAF unit all the military operators are likely to be using? :rolleyes: May I suggest if you don't understand then you ask, either on the radio there and then, or by land-line later!!

[mad_jock]

You ask for a service (25 miles from the radar head) and they ask you to set the QFE (something I find very surprising) and you ignore the request

Looks like lossie are still up to their old tricks. This is my experence from 4 years ago.

You get told to speak to lossie by ABZ when you start heading over westwards. And when I say told I mean told. If you decline the offer you then get it restated that they want to talk to you.

If you do then speak to them they will try and keep you at sub 2000 ft and remaining 20 miles to the south of Lossie and Kinloss. If you then decline that offer due to such technicalities of actually having a chance in hell of pulling off a forced landing, busting rule 5, generally getting the poo kicked out of you with the turbulence with the highish ground that they want you to fly over or of course remaining VFR. They then go to phase 2 of controlling you in class G airspace. Which is invent traffic in front of you and give you an immediate avoiding action due unknown traffic, of course moving you to the south where you didn't want to go. It works a few times then you spot the real reason for them wanting to move you is the circuit at Kinloss and they are trying to maintain radar sep on the circuit while keeping 3000ft clear for the instrument procedures. They control you in class G to try and maintain a exclusion zone way outside thier CMATZ.

So I completely know where the poster was coming from. And setting QFE is the least of your worries after accepting a "service" off lossie radar.

[Grabbers]

Mad Jock

Don't ask for a DS! The Lossie Controllers may give you TI but you just keep your eyes peeled. Or just Sqk 7000 and carry on your merry way using the 'see and avoid' principle. You don't have to do what 'they' say.


Simples

[mad_jock]

Mate your preaching to the converted.

I really don't think it matters what service you get off them. The only reason they want to speak to you is to control you for their benefit.

Hell they used to give you vectors and level instructions on a flight information service. So a meer technicality of the name of the service won't change them trying to run the NE of scotland like class A.

[WX Man]

I can't believe some people are even talking about using GPS height, Radalts and all sorts of other ways of measuring your altitude. The whole idea of everyone using QNH is to simplify things!

[mad_jock]

I hear you Wx.

It is quite funny though the idea that the rest of the world are going to change because a small section of the RAF thinks its a good idea.

[HEDP]

I can understand the ease of QNH for AT on scheduled ops but spare a thought for the other users who perhaps have to fly more circuits at different airfields than perhaps your average GA user. Having different altitudes to remember for each element of a circuit can be a nightmare and lead to eyes in the cockpit at the wrong time IMHO whilst looking up the altitudes to be flown.

Imagine 3 airfields in relatively close proximity each with a different elevation. That's three different airfield altitudes to remember, three different crosswind/baseleg altitudes and three different downwind altitudes. Unless you have a cracking memory or are eyes in instead of eyes out in the circuit then a simple QFE change and a standard circuit seems somewhat easier and safer to achieve with eyes out at all times.

Horses for courses; AT/scheduled ops with no circuits then it matters not a lot, lots of circuits at different airfields and the majority mil user then QFE seems somewhat safer. Overall safer if a standard is used for all military then QFE wins hands down. Doesn't mean that anyone has a lesser understanding of using either QFE or QNH however.

[thunderbird7]

Having had 12 years of QFE and now 12 years of QNH, I have to say that Qnh makes more sense to me now! Like everyone else, I hated the changeover in the early 90s and was glad when we went back to QFE but now, flying round the world, qnh makes perfect sense. I think I'd much rather know how high I am relative to ALL the ground around me - what about circuits at machrispanish & Kinloss with high/rising ground on the downwind legs? When I hit the runway, I don't need to know I'm at zero feet cos I can friggin feel it! ( The radalt tells me as well, if I was in any doubt! )

All IMHO of course!

[High_Expect]

Mad Jock has it not occurred to you that the reason Lossie ATC want to give you avoiding action is to keep YOU safe, as well as the fast jet mates hurtling around. I will goes as far as to say that I think your entire attitude is floored and that if you treat the rest of your aeronautical antics with the same slapdash uneducated manner you are an accident statistic waiting to happen. Lets just hope I’m not the unfortunate fast jet mate that you happen to stray in front of. Or even worse one of your passengers. Do you not think your duty of care to your passengers is more important than saving a few pennies by going direct and not talking to those “idiots at Lossie”?

Found your ATPL in a box of cornflakes did we?

You strike me as the same sort of pilot that only gives MATZ’s a 3nm berth as that all you have to under your rules.


High-Expect - we don't do personal abuse in here so that sentence has gone!

[mad_jock]

If you then decline that offer due to such technicalities of actually having a chance in hell of pulling off a forced landing, busting rule 5, generally getting the poo kicked out of you with the turbulence with the highish ground that they want you to fly over or of course remaining VFR.

Its was never refused without a reason.

But over the course of a year instructing I had students vectored into cloud, held high with not below instructions or level instructions so they busted VFR mins. Forced into flying at 400ft agl over hills. Which is a real no no in that area, that bit of airspace is all yours and it was drilled into them that sub 1000ft agl you were in the danger zone of meeting one one of the tonka's. And we all know that there is a huge whole in the radar coverage over the back side of easterton at the levels you lot fly at. One was told to standby when she called a pan due unsure of position because of glare off snow after being transfered by scottish info. It was such a contrast working with Tain range who I presume still are a cracking bunch of lads. It was a highlight for many a trial flight watching you boys/girls dropping bombs.

Actually if your in CAT you get a completely different level of service from them with no silly stuff thrown in. The few time's I have done VFR transits using them they haven't given any grief at all. It could be things have changed as my main experence with them was over 4 years ago now in GA. I had hope things had changed for the better, but a couple of the posts on this thread seem to indicate that they are not helping themselves again and GA traffic is avoiding talking to them. And if I had pax onboard I certainly wouldn't be at a level which would cause them to want to shift us; FL70. I think last time we went straight to INV radar from ABZ but I can't remember if that was the weekend or not.

To be honest your the first Mil person I have heard stick up for them.

[R SCANDAL]

I was flying JPs at Linton during the great QFE/QNH debate and was very pleased to have QFE whilst doing circuitathons and PFLs at Topcliffe, Dishforth, Leeming, Fenton, Finningley etc. However, I have since learned to "embrace" QNH and find that it provides much greater awareness of terrain. But what makes me titter is that we get a lot of chamfing from the FJ community about the vital nature of QFE but I have never heard it raised as a point at RED FLAG or COPE THUNDER etc. Just a thought.....

[mad_jock]

And as a note High expect under the rules I have to conform to the only thing I have to avoid is the ATZ. But to be honest I always do the airmanship things to do with MATZ although its very rare I go near the things these days.

And I have absolutely no problem at all with "for inbound instrument traffic could you please turn left 30 degrees and report if you require level change"

To which my reply would be "left 30 wilco"

Compared to the norm at the time.

After getting multiple civi things going whizzing by me with out a chirp of traffic information to suddenly get "left heading 210, maintain level 2000ft, readback" so you can see why Grabbers solution to the issue becomes the flavour of the day.

Which is quite strange as my experence in the vale of york would indicate that the first solution to dealing with GA is in the RAF ATC rule book. And everything was happy and people talked to them.

[Fareastdriver]

All those who insist on flying approaches on QFE showing them how many feet they are above the threshold are going to love flying approaches on QNH with charts and altimeters calibrated in metres.
The numbers are not so big and the instruments move a lot slower.

[WX Man]

I can understand the ease of QNH for AT on scheduled ops but spare a thought for the other users who perhaps have to fly more circuits at different airfields than perhaps your average GA user. Having different altitudes to remember for each element of a circuit can be a nightmare and lead to eyes in the cockpit at the wrong time IMHO whilst looking up the altitudes to be flown.

No, sorry, I don't buy this one. I actually fly lots of circuits at lots of different airfields when I'm working. I'm not exactly ETPS standard (far from it), yet I still manage to keep up with lots of different circuit altitudes.

And as for flying in close proximity to lots of different airfields, all with different threshold elevations, I'd say it's even more important to fly with QNH set. Makes coordination and traffic awareness just so much easier when everyone's flying with the same altimeter setting.

Flying with QNH set, as R Scandal points out, does make you much more terrain-aware.

[Romeo Oscar Golf]

The simple answer to WX man's question is - because they can. It's been taught that way for a long time and why the hell change. If you pilots Mil or civil cannot cope with QFE, QNH etc how the hell do you cope with mph, knots, or kmph, or feet, metres and flight levels, or lbs per min, galls per hour, or litres per week? In my day it was called airmanship and it was done mainly in the head. If you can't do it then stay on the ground where you belong.
I feel better now.... the Springbank helps.;)

[R SCANDAL]

Classic reinforcement of this point for me was when recovering to Lossie from the south, at low level and in "average" weather. In accordance with the BINA I made contact at 20 NM and was told by ATC "set Lossiemouth QFE of xxx". Whilst still sneebling through the hills, had I conducted a low level weather abort on QFE my altimeter would have been useless and given me no reference to safety altitude. A quick scribble of the airfield elevation on a kneepad (or read if off the LFC) and a cross check with the navigational consultant/co-pilot is all you need. (Single seat guys should inherently have the capacity ;)).

[airborne_artist]

If you pilots Mil or civil cannot cope with QFE, QNH etc how the hell do you cope with mph, knots, or kmph, or feet, metres and flight levels, or lbs per min, galls per hour, or litres per week?

Of course, no aircraft has ever taken on too little fuel because they muddled their units, and no aircraft has ever been overloaded with freight for the same reason....

Might it be better to keep things simple?

[R SCANDAL]

1. Now IMC after aborting, how do ATC deconflict me from other non-circuit traffic?
2. I have a contract with my formation to maintain contract sanctuary altitudes with reference to the granite, not my planned arrival airfield, (especially if we end up getting avoiding action.)

I know Lossie is only just above sea level but the principal remains and it is, in my opinion, a bad habit to start setting QFE without thinking of the ramifications. As for your first comment/question - fair point for discussion in the crewrooom but I wouldn't want to start the debate whilst aborting from low level. I am not saying that I am correct in my opinion, I am just adding my thoughts

[Capt Pit Bull]

Having been born and raised on QFE and then converted to QNH operations, I have to say its a no brainer.

You don't want to be using different altimeter settings at different airfields. That's just asking for trouble. It's the final hole in the lined up swiss cheeses. You want to be using the same procedures wherever you go.

QFE has some pluses, but the inability to use it at high altitude fields is a show stopper. (not just awkward / lots of twisting but total inability because the darn thing can not be set low enough!)

I do find it mildy amusing that elements within the RAF find the concept of correcting for elevation in the circuit or approach as being so daunting, given their usual penchant for pointing out the superiority of military pilots and training methods. Its only addition after all! Perhaps ask the MOD for a couple of plastic altimeter bugs. They probably won't cost more then £50,000 each ;)

[Pontius Navigator]

So the question remains why?

I recall the altimeter we had in the back in the Varsity. You could set it to zero on the ground or to the airfield elevation - there was no subscale. Once above transition we could set it to SPS.

It would have been possible to reset to QFE or QNH either by winding the height needles by a given amount (fraught with danger) or setting to the same as the pilot's altimeter. In fact neither method was taught. In those days navigation finished at the initial approach fix or overhead.

Now a good reason for using QFE could have been the approach aids of the day - an ACR7 approach with a 300 foot per mile descent. Or a Eureka homing. They were complicated enough at the time so the attraction of a 300 foot per mile system was clear.

With modern systems with precision height systems then QNH has advantages with deconfliction with the ground or other aircraft below transition.

[Fareastdriver]

You could set it to zero on the ground or to the airfield elevation - there was no subscale. Once above transition we could set it to SPS.


How do you do that without a subscale?

so the attraction of a 300 foot per mile system was clear.


It doesn't matter whether you use QNH, QFE or bouncing pingpong balls, the glideslope is still the same.

I received my Green Card on Vampires in 1961. I flew my first precision approach (ILS) in 1962. I flew my last as a commander of a public transport aircraft in December 2008 so I have been around a bit.

In the RAF the rules were simple, you flew QFE to the ground. Early on in civil life the situation was much the same until the ninties when you had a choice between of ploughing through the murk on either QFE or QNH. Then it stopped. The civil world was on QNH.

Apart from my company. A major helicopter operator in Aberdeen. Their ops manual said QFE, their simulator demanded QFE and in sympathy with their policy of using pounds instead of kilos like the rest of the world we had to request the QFE before initiating an ILS. Fortunately the operation was fairly parochial so you did not get into trouble elsewhere.

Move forward a few years and then come to Australia, China and the South Pacific. Same company, same ops manual. QFE was binned in Oz and Guadalcanal as being typical Pommie rubbish but not in China.

Step forward British captains and Chinese co-pilots in a country where ther are two settings. 1013.2 in a promulmgated airway or airfield QNH entering or leaving an airfield. We were different. We had a QFE setting in a clutch of airfields including Hong Kong, Shenzhen, Guangzhou and Macao. The new Chinese pilots were somewhat mystified about this, with good reason. BUT IT SAYS SO IN THE OPS MANUAL. You had to hand it to the Shenzhen controllers, though. They would get you QFE for you, come what may, normally just after you had passed the MAP. Eventually, but it took a change of managing pilot, the QFE requiremnt was binned and we entered the world of internationally accepted flying procedures.

So it is with some surprise that I discovered this thread. I am even more surprised that people are defending the status quo. I can understand where countries retain heights and flight levels in metres because they ALL do it in that country. Standardisation is the name of the game so all airfields in the UK should use the same common pressure setting, airfield QNH.

Those dreamers going on about radar and GPS altimeters, forget it. Should you make a 100% reliable radar or GPS altimeter that first time that there is a prang there will be lorryloads of litigation lawyers hammering at your door.

[Pontius Navigator]

How do you do that without a subscale?

The altimeter had a lubber line which we were told was the SPS setting. It was probably calibrated to ICAN.

It doesn't matter whether you use QNH, QFE or bouncing pingpong balls, the glideslope is still the same. . . I flew my first precision approach (ILS) in 1962.

Who mentioned precision approach? ACR7, Eureaka or whatever were azimuth only approaches. Watching blips on CRTs was dificult enough without having to add the range/height value to airfield elevation and then check with the altimeter.

Just a thought and it fits with the philosophy that 'we DO QFE' having forgotten WHY we do QFE.

I am not suggesting my proposal is the correct reason just that it is a possible reason.

[WX Man]

Fareastdriver- very interesting post. Many thanks for sharing your experience.

I've yet to be pursuaded that QFE is an appropriate thing to have set on an altimeter. R Scandal puts it very nicely:

A quick scribble of the airfield elevation on a kneepad (or read if off the LFC) and a cross check with the navigational consultant/co-pilot is all you need. (Single seat guys should inherently have the capacity)

I just hope that it doesn't take a serious incident to make the DAP recommend to the MOD that they start using QNH. The case for using QFE is tiny: the case for using QNH is huge. There is also a significant case for dispensing with RPS. Why would you want to set RPS and QFE when you're flying in the uncontrolled airspace around East Mids/Birmingham/Manchester... Surely, it makes sense for everyone in one area to be using an accurate QNH, to facilitate vertical separation and airspace avoidance.

[Fareastdriver]

Point taken on ACR 7s, internal radar approaches,, etc, but they don't do that any more, do they?????

[jindabyne]

My God! - and I have to fly with/be carried by, you lot into my twilight years. Whilst you're all arguing about altimeter settings which we all seemed to be comfortable with decades ago, I trust that you're all perfectably capable of flying the jet, hands on, in conditions that you're used to outside the simulator. I wonder? Old fart, I know --

[Solid Rust Twotter]

It's all QBI to me.

[Pontius Navigator]

Point taken on ACR 7s, internal radar approaches,, etc, but they don't do that any more, do they?????

Quite although we did practise internal approaches even less than 20 years ago. No, I was trying to find an historic rationale rather than justify its use now.

Another reason could be the lack of good mapping and consequently an inaccurate calculation of surface pressure. Set the altimeter to zero and at least you know it will read the same when you get back - slow moving weather systems.

Or how about air-to-ground weaponry? Again you needed to know your height above the target.

[Fareastdriver]

jindabyne

You're not taking this thread seriously, are you?

Personally, I do not care whether the RAF uses QFE or QNH because:

i. I have not flown in the UK for a few years nor will in the future.

ii. In a military zone it is their train set so they can do what they like.

The pages of this thread seem to have been taken up with complaints about a military radar advisory service demanding that a civil aircraft in civil class G airspace set an altimeter setting that is only valid in their Zone. He has a point. Landing at that military airfield he would have to follow their rules;--but he isn't, so why should he change from his normal altimeter setting procedures. He would expect that a civil airfield giving him the same service would advise him to fly on their QNH, This QNH is used in the circuit and, more importantly, for instrument let down and landings. Because the airfield will stipulate a minimum height within a certain sector then terrain avoidance is guaranteed. The recipient can elect to fly however he wants in VMC but it is up to him to stay legal. The military service that this pilot was complaining about did not fit into that criteria.

The point is standardisation. The vast majority of flying in the UK is civil in the same way as the vast majority of road traffic is civil. They all obey the same rules on the road, so they should in the air.

[US Herk]

The fact a professional organisation such as the RAF are still using QFE is beyond me. The claim that "remembering circuit heights" or "I want it to read zero when I touch down" are ludicrous. I, for one, don't look at my altimeter when I'm in the landing flare. I don't base my flare on altimeter readings, nor even much of my finals turn - I fly the plane.

Even if the circuit height argument was valid - what's the difference between the highest field elevation and the lowest here in the UK? A couple hundred feet? Make your standard circuit height 1500' and use pilotage in the finals turn to compensate...

What do you do when you go to the states and fly into places like Albuquerque or even Las Vegas? Let's not even talk about Leadville, Colorado at 9,927' field elevation!

QNH for fields in close proximity is far safer than QFE as all would be on the same setting.

I cannot get my head around the fascination with QFE...

[Wader2]

I think the modern answer, and it was mentioned early on, is because we can. It was retained, or reverted, in a fit of pique.

The then CAS< Sir Peter Harding drve the change to QNH from the very top. Now that was a rare thing with not just a top man but THE top man driving a change through against all opposition. Had he not blotted his copy book it is more than likely that we would still be on QNH. As it was, even before the revolving door had stopped, but th epresses were running reprinting all the old TAPS.

Now, having gone through the whole exercise twice we probably can't afford to do it for a third time. When we have one sqn and one airfield it will become economic to change then.

[Romeo Oscar Golf]

When we have one sqn and one airfield it will become economic to change then.

Not too long then:E

[Mike Oxbig]

Other places use QFE for approach as standard - Russia and other 'eastern bloc' countries for example. Now flying as a 'strawberry mivvie' all over the world and I admit it gets confusing toward Moscow when you are working in meters and QFE having become used to QNH and told to 'descent to FL9800 Metres' and then 'alt 900 metres QFE 1001'. It involves using a separate check list to get up the pressurisation system and another crib to convert the metres to feet for the Altimeter Alerting Device.
Mind you I don't find it as difficult a concept as some of my colleagues who have never flown in the military and get all upset about QFE!

MO

[bayete]

Clarification maybe needed for some, as I get the impression some poeple think that all the RAF use is QFE below TL.
IIRC for CCTs and App the RAF use QFE but once leaving the airfield set QNH, RPS or 1013 to go enroute as QNH/RPS will give you better terrain awareness. QFE may be set when transiting passed an airfield for coordination with cct traffic.
So does it really matter what the RAF use if you are not interacting with them?
For airdrop a local QNH, RPS or altimeter set using the radalt over terrain of know height was used.

I used QFE in the civvy world the other day when I had a double engine failure climbing out of Chambery and for the subsequent turnback, because of the very high workload it was the easiest way to know my height above touchdown for the PFL. Yes it was in the sim.

[PPRuNeUser0139]

Five years on - is it still the case that the RAF uses QFE?
Just a straight yes /no will do. No wish to re-ignite the debate.
Thanks

[H Peacock]

Yep, still using QFE at most UK military airfields. QNH when at the majority of civilian airfields.

[Rossian]

.....it was fun watching the brand new copilot trying to "zero" the altimeter at Embakasi prior to departure (his first overseas det).

The Ancient Mariner

[Basil]

QHH, QFE, millibars, hectopascals, inches, feet, metres - professionals adapt to the local requirement.

Although:
I'd posted this before but a good, and potentially lethal, example of mixed units and shortcuts:
Years ago whilst flying AEF Chipmunks at Cambridge on day off, US multi-piston appears on horizon considerably below nominal 3deg slope.
USMP: Cambridge, say again the altimeter.
C: 992
USMP: 29.92in?
C: Negative, 992mb
USMP: :uhoh:

[26er]

Years ago (late seventies/early eighties) we made an approach to Cologne behind a Lufthansa in marginal conditions. He landed, we didn't, so went round for another go. He reported cloud base figure well above our DH and we still saw nothing so diverted to Dusseldorf. It wasn't until we were safely on the ground that we realised his cloudbase report was based on QNH, whereas we at that time used QFE.

[Out Of Trim]

All RAF ATC units can offer you whatever you want, QFE, QNH, RPS, and you can have it it inches, millibars (don't like hectopascals..)

However, if you are going to join the circuit with Military traffic, you are going to get the QFE like everyone else!

As An Ex RAF AATC, I can still convert millibars to inches by memory of the old Yellow Flight Information Handbook! Ie.1016 mb converts to 30.00 inches, 1015mb to 29.97 inches.. etc etc. And I left the RAF in 1991.

And for the civvies asking about charsts jepp etc, The RAF have their own versions. And very nice they are too. Google AIDU and you will find even civvies can purchase a wide range of flight planning docs and charts from the RAF.

[Arty Fufkin]

ISTR Brize changed to QNH a few years ago. Long overdue. Perhaps in another 20 years they might have a few PRNAV arrivals and GPS approaches too!

[Danny42C]

In days of old, when knights were bold, and we had wooden aeroplanes and iron men, the RAF used QFE all the time for circuit work and general local flying (and you used the word "height". If you were going further afield, you changed to "Regional QNH". This was IIRC: "The lowest forecast QNH for two hours ahead for the Flight Information Region in which you were flying" (and you spoke about "altitude").

Then there was a "Transition Altitude" (can't remember, but I think it was set by the FIR), at which you set 1013.2 (I believe it is 1014 now - btw, what is the Q## for that ?) and we started talking about "Flight Levels". I am not sure when we began doing this, certainly I was flying Meteors and Vampires up to '54 and we weren't using the term (or did we only do it in Controlled Airspace ?) I was instructing at the ATC School (Shawbury) from '64-'67, and to the best of my recollection, that was what we were teaching then.

In US and UK '41-'42, India and Burma '42-'46, I never used anything other than QFE (ie, I zeroed the altimeter when I got in, and never touched it again).

Of course, the Altimeter Setting Accident was, sadly, fairly common in those days. Our older members may recall the Near Miss of the Century - the Nairobi Comet - in which thirty-odd BOAC trusting pax were (inadvertently) taxied, at some 200 mph, in total darkness, somewhere on the E. African scrub, for about 100 yards or so before the horrified crew got back in the air :eek: (and landed safely in Nairobi !)

The incident (in the '50s) is well documented: if you ferret around in Google/Wiki, I'm sure something will turn up.

D.

[thing]

It's still 1013.2 Danny. I've no idea why the RAF still use QFE either.

Don't know how transition levels et al were defined in your day but these days transition altitude is the altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes. Transition level is the lowest flight level available for use above the transition altitude and the transition layer is the airspace between the transition altitude and the transition level.

The other thing we need in the UK is a common transition level, one that is preferably above our highest mountains...

[Background Noise]

You mean a common Transition Altitude - and it is being looked at Europe-wide.

[thing]

TA of course, I stand corrected by your correction sir. Any idea how high it's proposed to be? I've heard mutterings of 6,000 but surely you would run into the same problem in the mountainy bits of Europe? I believe in the US it's 18,000 which seems to make more sense.

[Background Noise]

CAA docs here, relating to UK initially, but it is being looked at for Europe.

Consultation - Transition Altitude | Consultations and Responses | About the CAA (http://www.caa.co.uk/default.aspx?catid=1350&pagetype=90&pageid=12919)

[Boudreaux Bob]

Clinging to the QFE Altimeter setting is so....well Wellington like. Then add in all this Transition Height, Regional QNH, and the like. You folks should simply join the real World and go to a single Altimeter setting using QNH below the one Altitude such as the US FAA does.

It makes sense.

It makes things far more simpler and SAFER.

But then whenever did KISS hold sway with the CAA or RAF?

[HTB]

Or who use metres for vertical measurement, or another reference for altimeter setting, or crossing an area where there is steep pressure gradient and a great range of high ground...

Mister B

[AutoBit]

Boudreaux Bob,

Im sure this has already been said but the whole reason why the UK mil use QFE is to keep it simple. High altitude on 1013, then move across to QFE when switched to either Director or Tower and cleared to a 'height'. How is that complicated? What bit of the KISS principle does that infringe?

Mil ac, particularly FJ and Rotary, fly a lot of visual arrivals (via VRPs) and visual ccts as they save fuel and time. In my experience its far easier to have initials at 1500' and fly a cct at 1000', then at say 2265' and 1765'. It also has the advantage of being the same for every airfield you go to. The alternative is to use the radalt, but this has problems when your airfield is surrounded by hills.

Simple.

[Boudreaux Bob]

Yet you still have to use QNH in addition to the QFE don't you?

Of course there is the local QNH, Region QNH, along with the Standard Setting of 1013 for Flight Levels.

We have found it easy enough to do the mental gymnastics you describe and at the same time be able to use a common reference for Terrain and Obstacles which are all based upon MSL which is a nice fit when using QNH Altimeter settings. All of our charts show AGL Heights for Obstacles thus doing the math for you.

Our rules have us using the most up to date QNH Settings within a 100 NM's at a Minimum while Enroute although good practice is to use one from close by and when operating to an airfield or location close by, the setting for that particular Airfield.

It is all what One is used too in a lot of ways.

I have done both the UK and American method and very much find the UK procedures far too complicated and subject to finding the wrong setting showing up.

If you recall that wonderful Memo about Altimeter Settings and the manipulations required for an IF Approach with a Go Around with the attendant shift of controls then you can agree it can get tedious at times using UK Rules. (The Memo was a spoof on BA's system if you recall.)

If FJ's have problem doing Maths perhaps bringing back NAV's might be a good idea you think?

An example of why a QFE Setting might have some flaws:


http://i.kinja-img.com/gawker-media/image/upload/s--arBlqyqf--/c_fit,fl_progressive,q_80,w_636/18e958s15bds6jpg.jpg

[AutoBit]

Never used both QNH and QFE. I would agree that it starts to get complicated at that stage. As I mentioned; the decent is flown on 1013 until you are cleared below TL and then you fly a height rather then an altitude. Its still only one altimeter change. Same for the climb.

And the BA spoof was about the monitored approach. Not sure what it had to do with altimeter settings?

[Basil]

Boudreaux Bob, Skied past there a few times.
On QBB (Quinine{Gin}, Beer & Brandy) :}

[ShotOne]

Autobit, so how do you know your height above terrain? Surely pretty important in the above instance. All QFE tells you is height above threshold

[AutoBit]

UK Mil app plates have the step heights based on QFE, so it's no different to flying a QNH app.

Im not really that fussed about QFE or QNH. Ive done both. Both work. Im just a touch surprised by some of the comments on here that flying QFE is this crazy, un-safe procedure.

[Bob Viking]

1. Shotone. QFE is no better or worse than QNH at giving you your height above terrain. One tells you your height above sea level the other above runway threshold. If I have Valley QFE set (for example) it is not going to stop me flying into Snowdon any more than the Holyhead QNH if I am stupid enough to be tooling around at low level with low SA. Since there are no airfields in the UK below sea level the worst that could happen, if I accidentally left QFE set, is that I would be higher than I think I am whilst blundering around in Snowdonia.

2. Boudreaux Bob. I hear your argument but let's use the example of a display pilot flying an aerobatic routine over an airfield. Would you rather know your height above sea level or your height above the runway? Clearly my thoughts are influenced by a well known example at Mountain Home (where QFE would not have been practical) but in the UK it would work very nicely. Landing in poor weather has similar connotations and I like knowing my height above the runway whilst having SA on surrounding terrain.

For the record I currently fly in Canada where QFE is not utilised or practical (the highest airfield I have been to recently was Rocky Mountain Municipal in Boulder and QFE sure as hell wouldn't work there) but I have flown a lot in the UK. I can cope fine with either system and I really don't care one way or another but I really can't work out why some people think QFE is unsafe.

I guess it depends what you've grown up with. Everyone in this country drives on the wrong side of the road but I've managed to adapt. Mostly.
BV:E

[ShotOne]

Bob, well I'm not especially fussed if this is what the RAF want to do but I completely disagree with your point 1. In a mountainous area QFE gives no information relative to terrain heights/spot heights in any given place.

You appear to concede this point in your final para. Agreed, it doesn't matter much either way for most UK RAF bases but why rely on a system which "sure as hell wouldn't work" in many places?

[Boudreaux Bob]

I am not suggesting it is "Unsafe" per se.

What I am suggesting is that QFE has some built in issues as it pertains to the runway elevation at the approach end. (Unless my memory fails me.) and as in the photo I posted we can see that might not apply to the entire runway as there could be quite some difference in some locales.

Determining a Circuit Height at an airfield would be easier using QFE but then I am used to doing all that higher math(s) required to do the exact same thing using QNH.

The advantage i see is in determining safe Altitudes in the surrounds of the airfield as there are MSA posted on Maps and Approach Plates which are in MSL rather than absolute heights.

If you guys want too use QFE and are happy doing so.....have at it.

I just happen to see it as being less utilitarian than using a QNH setting.

If the RAF were to suddenly have a change of heart I am sure it would tip some Worlds upside down and require lots of changes to Approach Charts, Maps, and SOP's which itself could present a Safety Issue as any major change does.

That very few places in the entire World use QFE should be some hint but then it would defy the Wellington Rule mandate. Other than the UK or RAF Bases....are there any that use QFE as standard procedure?

In the United States, it is impossible to use QFE in a great part of the country as our terrain is just way too high.

By our standards the UK is all flat land with just a few hills. Some are rather steep but none are really very high.

In Death Valley while setting at a Below Sea Level elevation one can look up at a 13,000 plus foot high Mountain which demonstrates the kind of terrain differences we have.

I guess a question is begged. What changes to procedures does the RAF make when using a QFE altimeter setting is impossible?

[DITYIWAHP]

I think QFE appeals to the CFS old-school nibber types who like circuits to be flown at a whole number on an analogue altimeter. No ugly 46 ft etc to look at, and rounding up or down by a few feet is.... well.... imprecise! Baaaa!

Just think.... Approach plates with only one set of numbers on them and a training mindset that prepares you to fly into non-UK mil and any civilian airfield in the world. That's crazy talk!

[AutoBit]

Not sure how flying a QFE approach fails to train you for flying around the world or into non-mil airfields. Its the same procedures for QFE and QNH, its just the datum that has changed.

[thing]

Its the same procedures for QFE and QNH, its just the datum that has changed.

Couldn't agree more so for the purposes of simplicity why not stick to one datum? The argument for making ccts easier because you're flying 'round' numbers is nonsense really, if you can't add a thousand feet or whatever the cct height is to an airfield elevation then maybe it's time to hang up the flying gloves. Apart from which and not really connected to the issue of QFE but any aviator worth their salt should know what a thousand feet looks like without an altimeter. Has the ability to fly a perfectly good circuit anywhere without an altimeter been lost?

[Party Animal]

BV,

Minor correction to your previous:

QNH gives you an 'altitude' above sea level.

QFE gives you a 'height' above a datum.

But we all know what you meant......

[just another jocky]

Has the ability to fly a perfectly good circuit anywhere without an altimeter been lost?

Of course not, but when your visual circuit height is a mere few hundred feet below the instrument approach of another airfield, then "gashing it" isn't really an option.

Even at Elementary training, the ASI is covered up to see how well the student copes. Perhaps I'll try the altimeter next time too.

I don't see too many issues with the RAF flying at various places around the world. I've flown my fast jet into many airfields in the US with no issues at all. I've operated my fast jet in the mountains of northern Afghanistan, in the dark, at low level without issue.

So clearly we're doing something right.

Bored now.

[Fareastdriver]

Same here.

I would climb into an aircraft with dials reading knots and feet and fly around China .i.a.w metric flight levels and QFE. Then I would step into an aircraft instrumented with kilometres and metres and fly around Hong Kong using conventional flight levels and QNH.

Don't remember ever flying into anything.

[Boudreaux Bob]

At your advanced age it is a miracle you even recall flying anything at all;)!

[Private jet]

The reason the UK mil use QFE is because they do not like change. It's as simple as that.

Its all been said before but QNH references your altitude with respect to surrounding terrain (not just height above the airfield reference point or runway threshold) and also the base of any controlled airspace above. Both of these things are very useful to know. The only time I used QFE I think was going to Northolt and also when I converted my FAA licence back in the UK and I think it was all part of making the IR test awkward. QFE/ airfield QNH / regional QNH/ standard1013- with all sorts of different transitions to boot, changing the settings every 5 minutes it seemed and that idiotic practice of setting the altimeters to completely different settings at various times in the flight. So, with two altimeters in a spamcan if one is faulty how can you tell a fault even exists? but then of course without a third standby how would you tell which one? The jet aircraft I flew all had 3 pressure alts and nearly all had rad alt so QFE was totally redundant, it told us nothing, in fact using it would limit our "altitude awareness". Don't supa-dupa military aircraft have rad alt's?

[Bob Viking]

How's your back? It must be sore with the weight of that sizeable chip on your shoulder!
BV:E

[just another jocky]

Its all been said before but QNH references your altitude with respect to surrounding terrain (not just height above the airfield reference point or runway threshold) and also the base of any controlled airspace above. Both of these things are very useful to know. The only time I used QFE I think was going to Northolt and also when I converted my FAA licence back in the UK and I think it was all part of making the IR test awkward. QFE/ airfield QNH / regional QNH/ standard1013- with all sorts of different transitions to boot, changing the settings every 5 minutes it seemed and that idiotic practice of setting the altimeters to completely different settings at various times in the flight. So, with two altimeters in a spamcan if one is faulty how can you tell a fault even exists? but then of course without a third standby how would you tell which one? The jet aircraft I flew all had 3 pressure alts and nearly all had rad alt so QFE was totally redundant, it told us nothing, in fact using it would limit our "altitude awareness". Don't supa-dupa military aircraft have rad alt's?

What a load of tosh!

Are you seriously suggesting rad alt is used for anything other than low flying (ie NOT in a radar or visual circuit)? What exactly do you fly?

As for the rest....ill-informed and incorrect.

Please.....if you don't like it, don't fly it. The rest of us are happy (clearly in our ignorance) and have managed to amass 000's of hours in fast & pointy things (without the assistance of anyone else for many), rotary jobbies and big fat slow things (yes, like the stuff you fly?).

QNH may well work for you and that's great but please don't stick your nose in where you clearly don't understand the job we do and the methods we use.

Even more bored now and banging out of this thread! :}

[thing]

I don't think it's an issue of 'we'll continue to use it because we use it'. I have no problem using QFE, I use it virtually every time I fly. I have no problem driving on the right when I go to Europe or the States; but wouldn't it be better if everyone drove on the correct side of the road? It's probably my OCD that desires uniformity. QFE works just fine but there's no reason to have it. Not that I can see anyway; however as a civ end user I respect the opinions of the more experienced and professional aviators on this sub forum. If you say it's essential then I can't really argue with you.

[Fg Off Bloggs]

Can't believe that this thread has been resurrected - 5 years it's been on here!!!!!

Surely the simple answer to the daft question is "because we want to and we like it!"

Fg Off Bloggs
Just here to help and take a kicking!:ok:

[thing]

because we want to and we like it!

Just like my wife and her damned Radley handbags then.

[Boudreaux Bob]

My My.....imagine that....."Attitude" from a RAF FJ! Whatever is this World coming to these days?:oh:

[rarelyathome]

If there is only one engine that goes quiet soonish after take off and no Martin Baker letdown option things are likely to be a bit busy. Doing mental arithmetics to add elevation to the QNH is one more thing likely to get in the way of speedy decision making when every second counts.

Why are you turning back Bloggs?
Cos I've got enough height.
But you've got altitude set.
§h!t :uhoh:

[Boudreaux Bob]

Gee.....does that mean all these years and Zillions of flight hours....the Yanks have done it all wrong? You have any accident statistics that would prove your point?

Are US Accident rates higher than the UK for such a reason?

Surely you know of what you speak so you should be able to corroborate that or you would not be saying what you are.

I have not flown out of my home airport in probably thirty years but I still remember the Field Elevation is 960 feet. How hard is the Math(s) to keep track of your cardinal heights which in our case were 400 feet and 800 feet.

Even if I merely rounded up to 1000 Feet and then added my numbers, would it really make a damn?

Considering acceptable Altimeter Instrument error is 70 feet plus or minus, and some variation in actual Barometric Pressure due to normal pressure changes between recordings, just how accurate does one need to be in the math(s)?

What tolerance do you demand in determining a height at which you will turn back or not? One foot....Ten Feet....a Hundred Feet....Five Hundred Feet?

Is it the Altimeter Indication that is your final factor or your Mark I Eyeball and Brain working in conjunction with each other that is the final bit of information that facilitates that decision?

[deltahotel]

My My.....imagine that....."Attitude" from Louisiana! Whatever is this World coming to these days?

I've used both (a lot) am happy with either and really don't care. If the military want to use QFE then let them. fwiw in the training environment with lots of visual ccts I found QFE easier both as student and instructor.

[airpolice]

I'll not bore you with the details, but last week I was flying between the downwind leg and the runway, but in the "wrong" direction, at 800 feet (QFE) while a Typhoon who was downwind was heading towards me at 1,200 feet (QFE) just a little to my right.

It's quite common for us to be in mixed height circuits, and going in different directions. It all works rather well on QFE.

I suppose we could just learn to fly at 839 feet or 1,239 feet (or 539 feet for Helicopters) but I don't want to be looking for a 39 foot mark on the altimeter.

As for landing, I don't normally look at the altimeter after 300 feet in the descent, by then I'm looking out the front.

[Boudreaux Bob]

Can you fly to a one foot accuracy no matter which "mark" you are looking for?

The key is for everyone to be using the same Altimeter setting whichever is chosen as the Reference and stick to the correct Height or Altitude.

Years ago we had three BarAlts on our helicopters and no RadAlt.....and in Norwegian waters the Field SOP in the Ekofisk was based upon RadAlt Height which the Helicopter Service aircraft had in addition to their BarAlts.

They did not provide QFE settings as they used QNH for their BarAlts.

Thus a small problem in traffic separation standards.

[Bob Viking]

There's a phrase that a friend of mine taught me once that I think applies here:

It's not wrong, it's just different.

It appears that you're the only one who has really got that upset about it so maybe it's time to just sleeping dogs lie? We do things differently sometimes and it works for us (as I've previously said I couldn't really care either way). At some point in history you guys started driving on the wrong side of the road and changing the way you spell things but we long since stopped caring about it.

BV

[Boudreaux Bob]

BV,

You are absolutely correct! I am quite upset and just cannot leave Sleeping Dogs alone!

The key is for everyone to be using the same Altimeter setting whichever is chosen as the Reference and stick to the correct Height or Altitude.

I am taking issue with the silly excuses being given by some.

Perhaps you are looking for insult where none is offered.

[H Peacock]

Are US Accident rates higher than the UK for such a reason?

Well, here's one!

On Wednesday the 21st, the Air Force Accident Investigation Board held a news conference at the home of the Thunderbirds - Nellis Air Force Base - to announce what caused an F16 to crash last September.

According to the accident investigation board report the pilot, 31-year-old Captain Chris Stricklin, misinterpreted the altitude required to complete the "Split S" maneuver. He made his calculation based on an incorrect mean-sea-level altitude of the airfield. The pilot incorrectly climbed to 1,670 feet above ground level instead of 2,500 feet before initiating the pull down to the Split S manoeuvre.

How many display pilots try to complicate the issue by using QNH? QFE for me:O

[Boudreaux Bob]

You refer to the Mountain Home Crash I assume.


The difference in altitudes at Nellis and Mountain Home may have contributed to the pilot's error. The airfield at Nellis is at 2,000 feet whereas the one at Mountain Home is at 3,000 feet. It appears that the pilot reverted back to his Nellis habit pattern for s aplit second. Thunderbird commander Lt. Col. Richard McSpadden said Stricklin had performed the stunt around 200 times, at different altitudes during his year as a Thunderbird pilot.

McSpadden says Stricklin is an exceptional officer. "He is an extremely talented pilot. He came in here and made an honest mistake," says Lt. Col. McSpadden. But that mistake has cost Stricklin his prestigious spot on the Thunderbird team. "He's assigned to Washington D.C.," says McSpadden. "He's working in the Pentagon there in one of the agencies."

The maneuver the pilot was trying to complete is called the "Split S Maneuver." The stunt requires that the pilot climb to 2,500 feet. Investigators say Stricklin only climbed to 1,670 feet before he went into the spinning roll.

The board determined other factors substantially contributed to creating the opportunity for the error including the requirement to convert sea level altitude information from the F-16 instruments - to their altitude above ground and call out that information to a safety operator below.

But the Air Force has now changed that as a result of the crash. Thunderbird pilots will now call out the MSL (mean-sea-level) altitudes as opposed to the AGL (above-ground-level) altitudes.

Thunderbird pilots will now also climb an extra 1000 feet before performing the Split S Maneuver to prevent another mistake like the one on Sep.14, 2003 from happening again.

Captain Chris Stricklin has been in the Air Force since 1994 and flew with the Thunderbirds for the first season now. He has logged a total of 1,500+ flight hours and has received numerous awards. He served as a flight examiner, flight instructor and flight commander.

[H Peacock]

You refer to the Mountain Home Crash I assume

Yep, that's the one. Trying to work out the altitude to commence a manoeuvre which needed a given Height above the runway to complete.

Use QFE, just look for the correct number on the dial; same number every time. Use QNH then you have to do a sum - albeit fairly simple - then look for this number on the dial. Different number at each venue. Get the sum wrong and... Well it made a great photo!

[Boudreaux Bob]

Must be a FJ thing....otherwise they would be NAV's if they could do math(s).:uhoh:

Mountain Home AFB has an elevation of 3146 feet. Would an RAF aircraft be able to use a QFE setting at that elevation?

[H Peacock]

And all because they cannot add, it would appear

Well, it would appear neither could young Stricklin in his F16!

When Stricklin realized something was wrong, he exerted maximum back stick pressure and rolled slightly left to ensure the aircraft would impact away from the crowd should he have to eject, the Air Force said. He ejected when the aircraft was 140 feet above the ground. There was no other damage to military or civilian property. Also, the board determined other factors substantially contributed to creating the opportunity for the error to occur, including the requirement for demonstration pilots to convert AGL elevations to MSL altitudes, and performing a manoeuvre with a limited margin of error. Instead of just zeroing the altimeter to deck level as a result of the crash, procedures have been changed to require that Thunderbird pilots climb an extra 1,000 feet before starting the Split-S manoeuvre.

[Bob Viking]

We're on a new page now so rather than reading back through previous pages we'll just have the same conversation over and over ad nauseam.

BB you know the answer to your question so why ask?

If I were to fly an RAF aircraft to Mountain home (or somewhere of similarly lofty elevation) I would use QNH. Does that make me better than you because I am eminently capable of operating safely on either system?

BV:rolleyes:

[Boudreaux Bob]

BV,

As I do not fly RAF Aircraft and have no idea what capability your altimeters have, and knowing the RAF is bound to have some policy, SOP, or Pilot Instructions re setting of Altimeters, perhaps you or some other RAF Pilot could answer that simple straight forward question.

It would be educational to have an explanation of how you determine when QFE settings will not be feasible and thus necessitate your use of QNH instead. That would also tell us what the limitations of the QFE method might be too.

Nothing sinister here, just somewhat curious how you go about your business as it is much different than the way most of us are experienced in doing.

[Easy Street]

BB,

There's no need for any mathematics or conversion tables. It's a simple 2-step procedure:

1) If in a country where QFE is used at military airfields (e.g. UK), use QFE at military airfields.


2) If elsewhere, use QNH.

Personally, I would rather use QNH at all times in the UK as well. Having 2 ways of saying the same thing is great if you're writing a novel, but it goes against principles of standardisation and seamless interoperability that the world of aviation generally subscribes to. It's not difficult to switch from QFE to QNH when operating abroad, but then in my humble opinion it's not difficult to fly a circuit on QNH either. Certainly not difficult enough to bother maintaining a national difference in standards.

[H Peacock]

BB

I'll largely agree with the reply from Easy Street. As to why we use QFE, this has already been stated, but in short it often works better than QNH.

When sat in the back teaching visual circuits I want my stude to learn one set of figures, ie base your low-level, flapless, glide circuit or PFL critical points ALL on height above touchdown. It is easier. My terrain clearance is largely visual/procedural, ie the circuit patterns are based around the local geography. One set of figures are much easier to remember and work every time. Engine failure followed by a possible turnback or ejection, again just one set of figures to think about, especially in the heat of the moment. QNH would make this all somewhat more complex with no advantages.

Whenever I use my kitchen scales (not often!) I could make allowance for the weight of the bowl; I don't. I zero it with the bowl attached to get a new zero datum. I do the same when I check the tyre pressure on my car. 44psi or 3 bar works a treat, but it is actually an absolute pressure of 4 bar. Yes, we could make it harder and do a little extra maths, but why? Within the MATZ we are all on QFE.

Now send me to Luton in my wonder jet and I'll set QNH. All straightforward bar some additional number crunching so I can cross check my alt v dme as we trundle down the ILS (touchdown elevation + 300ft/nm). Approaching DA I hit TOGA and go around knowing I was about 200ft above the runway. In the preceding pattern I knew my vertical spacing from all the other traffic that I could hear on the same freq.

Off now to St Petersburg (okay, I'm now in the sim) and I'm probably back to QFE. Just as well as I also tell the altimeter to display in metres and not feet hence losing me the SA I have gained by operating in QFE.

Back home again, and if I'm lucky enough to be leading a formation display then again I want just one set of figures at each venue = QFE. Gate heights always the same, flypast heights also the same. Just can't afford to be descending to an incorrect altitude - even if it was a simple sum! Frees up some SA to use on other more important aspects of the display such as the wind! Even at a non-airfield based venue I'd like a display QFE if available.

There you go, QFE used when it is most beneficial, but QNH does also have its place.

[Bob Viking]

BB.
Genuine apologies, I thought you were being facetious. Most of our altimeters will wind down to about 850 mb/hp so once you get up to airfields about 3000' amsl QFE becomes tricky. Hope that answers your question.
BV

[Boudreaux Bob]

Ours cover a range of 28.0 to 31.0 Inches which is 3,000 feet as well.

A look at our map showing terrain elevations will show why we cannot use the QFE setting in a whole lot of the country.

[Bob Viking]

Which is why I conceded several pages ago that QFE would not work in large parts of the USA.
Anyway I think this one has definitely run its course so I shall leave it there.
Toodle pip.
BV

[vascodegama]

HP

Not always true about the exclusive use of QFE in the MATZ. Prior to the change to QNH at BZN (OK not actually a MATZ but not a factor) the civvies were allowed to use QNH in the same pattern as the rest of us on QFE . I always wondered about the potential for problems with a 300 ft airfield and 500 separation and mixed settings. Now that BZN uses QNH one would be forgiven for thinking that the potential for mix up has gone. Unfortunately there are exceptions allowed -visiting FJs if memory serves.

Isn't the main point that QNH is the one system that covers all cases. What do the FJ mates set at Kandahar ? I do get the argument about students but do those at Shepard (spelling? ) in Texas have problems. IMHO the reversion to QFE (was it in the nineties) was a backward step.

[Easy Street]

Vasco,

FJs at KAF use QNH. The FJ community isn't the driver for keeping QFE, although some seem to think it is (e.g. Brize offering QFE to FJs by default). I think the most ardent defenders of it are the instructional community, although as you correctly point out, if students everywhere else in the world can cope with QNH, one hopes that our potential future F35 and Typhoon pilots would also manage!

[ShotOne]

That seems to be borne out by the posts here, easy. Of course it would be wrong to imply QFE doesn't or won't work. Indeed in the training scenario I can see the attraction. But throw in terrain or a trip overseas and it doesn't work. why have an SOP which has to be ditched as soon as things get interesting?

[ACW599]

Back home again, and if I'm lucky enough to be leading a formation display then again I want just one set of figures at each venue = QFE.

Out of interest, what altimeter datum do non-RAF formation display teams use?

[Duncan D'Sorderlee]

Easy Street,

Not sure how you come to the conclusion that the instructional community are the most ardent defenders of QFE. I've been instructing for 14 years and no-one has ever asked me for my opinion. That said, if they did, I'd find it difficult not to argue that having 0 on the alt when you are on the ground was a good thing - I'm not sure I'd be ardent about it, though. However, when you spend most of your LL time over the sea, the QFE/QNH debate is kind of meaningless. :)

Duncs:ok:

[Boudreaux Bob]

I'd find it difficult not to argue that having 0 on the alt when you are on the ground was a good thing - I'm not sure I'd be ardent about it, though.

The inconvenient truth in all this is that is not necessarily the case. (0 showing....)

As not all airfields are dead level flat and some can have marked differences in elevation then that "Zero Feet" indication might only be related to one very specific place on the Airfield (assuming no Altimeter Error).

Barometric Altimeter indications in reality are only "close guesses" as to where the aircraft is in relation to the ground.

Thus, when I hear the "0" number being thrown about I just have to wonder about the level of pedantry to which I am being confronted.

Just how accurate is that "0" indication in the best case.....or the worst case all things being considered in a rational reasonable way?


The FAA's advice re International Flying by US Pilots:

Altimetry

The U.S. and many other countries use inches of mercury to measure barometric pressure. Other countries use millibars (e.g., hectopascals or hPa). Some aircraft altimeters will display both; however, if only a single-display altimeter is available, it is necessary to have a conversion chart available.
The U.S. and other western countries use QNH altimeter procedures. Some countries (e.g., Russia) use QFE altimeter procedures. When operating under QFE altimetry, your altimeter will indicate zero when on a datum point somewhere on the airport surface, commonly a runway threshold. Complete understanding of the rules and procedures required to fly under QFE altimeter procedures is critical when operating in these countries. Some airports will supply QNH on request.
While the transition altitude/flight level in the U.S. is 18,000 feet (FL 180), it varies greatly elsewhere, and the flight levels may begin as low as 3,000 feet (FL 30). You may be assigned Flight Level six zero (FL 60), for example.
A few countries (e.g., China) use meters instead of feet. For altitude and speed, you will need conversion charts.

[ShotOne]

Duncan, perhaps this was your point but throwing low level into the argument, over the sea or anywhere else is the reddest of herrings. Whether on QFE or QNH, nobody is, at least I hope they're not, using a baro alt to judge height above any given bit of terrain?

[Easy Street]

The Thunderbirds have always flown with QNH (unsurprisingly, being American) but they used to 'think' in QFE. That was, until this accident (http://www.f-16.net/f-16-news-article968.html). Now, they both use and 'think' QNH.

[clunckdriver]

One might just as well ask as to why the RAF stayed with "fighting area attacks" and using close formations with a "weaver" right into the Battle of Britain, that is until punishing loses forced them to follow the Luftwaffe with "pairs" and "finger fours", Frankly, the use of QFE and all the rest of the "Q code" should be a thing of the past, indeed I'm told that the pilot course I was on at FTS was the last one which had to learn the" Q code ". The military establishment is always resistant to change , One only has to read about the reception DH got from the "Blimps" at the top when they proposed the Mosquito, or Sir Frank Whittle received in his early turbine work, the RAF could have beaten the Germans with a jet into service easily had they been of more progressive outlook. This attitude is why the RAF still uses QFE, its nothing to do with any real advantage or disadvantage, if you wish to argue the point we can meet you at Puntzi Mountain, or any of a number of strips surrounded by big rocks, but I will be on QNH!

[H Peacock]

ShotOne.

Duncan D's reference to low flying is most certainly not a red herring. I'm sure the SOP for one particular (ex)user of the low flying system over the sea would be to set the baro alt to match the rad alt in S&L before using the baro as the master! Only way to do it at 100ft. Had a go myself in the Bucaneer sim long ago at Lossiemouth.

Not sure about the Nimrod, but I've used a similar technique when conducting low level trials (manoeuvring) over the sea. The rad alt is great for S&L but not much else!

BB

As not all airfields are dead level flat and some can have marked differences in elevation then that "zero feet" indication might only be related to one very specific place

Agreed about airfields not being level, but QFE is invariably factored for the in-use touchdown zone. Not unusual at some fields to get a QFE change whenever the runway changed. Furthermore, most altimeters are accurate enough to read a pretty constant '0' at the threshold.

Don't however think we are using the altimeter 'approaching zero' to initiate the flare! It simply means that every airfield I fly visual circuits at I will be looking to fly downwind at 1000ft, halfway round finals at 650ft, roll wings level at 300ft over my 1 mile point. I may be a tad high or low, but it will there or thereabouts.

If you've not used QFE much then, like anything you are unfamiliar with, you'll be reluctant to change away from QNH. Trust me, having been using altimeters for over 30years in a wide a range of the aviation spectrum roles, QFE most certainly has it's place.

[Boudreaux Bob]

I am sure it does.

Be that as it may, it does not eliminate any mental gymnastics while doing a Circuit or operating within the MATZ if there is any significant deviation in ground elevation or obstacles with some height.

As you point out, the QFE applies to the landing threshold of a particular Runway.

If one uses QNH, a quick glance as the posted MSA for the Approach or Runway in use gives one a fixed altitude at which safe flight is assured in the specified area to which it applies.

I would assume, while using a QFE setting, one has to make sure the selected height being flown is at or above the MSA for the area one is operating within.

Personally, I would find it much easier working off a single altitude reference but understand some are quite happy doing it differently as that is what they are used to doing.

[Darvan]

ShotOne, Buccaneers would routinely fly at 420 kts at 100 ft asl with reference to the radalt. On accelerating to 550 (plus) knots, the baro alt would be matched to the radalt so that when entering a 4G turn with the radalt now unlocked, 100 ft asl could be monitored and called by the back-seater. In a glassy sea state, the baro alt, and the nav's monitoring of it, was absolutely vital to support accurate and safe height keeping in a high G turn.

[Deepest Norfolk]

Simple answer would be because it's easier to look at your altimeter and see what height you actually are above the airfield on a low vis, critical approach, rather than to look at it and remember to correct for height above seal level.

DN

[ShotOne]

Not so, DN. On a low vis approach (decision height<200') all heights, call outs and minima are referenced to rad alt.

Very interesting, Darvan/Peacock, although in the context of this thread I stand by my "red herring" comment since such a unique self-generated alt setting is neither QFE nor QNH.

I'm intrigued that formation aerobatics has been thrown in as a reason for QFE. Although USAF's Thunderbirds use QNH, they had adopted the practice of giving their height checks and "gates" for various manoeuvres as heights agl rather than altitudes. This practice led to the spectacular (luckily non-fatal) crash described by easy st. and ceased thereafter. But great video on youtube!

[walter kennedy]

Ah, this is still on-going.
Suppose you were going to a point on the ground that was the same elevation as your departure point, it was not very far away, isobars nice and spread out that day in the immediate region, and there is no really close station to give you QNH at that point you are going to/by? - well what better could you use than the setting that gives you zero at your departure point? - the QFE?
Funnily enough, ZD576 had one subscale set to the QFE at Aldergrove and the HLS at waypoint A on the Mull had the same elevation :eek: Oh and the RADALT idea wouldn't have been much good with a sudden rise up the cliff from the sea to that HLS.

[ShotOne]

The radalt works perfectly in the context of my post, Walter. Such procedures are carried out hundreds of times every day in all kinds of weather around the world. The baro alt, with no exceptions that I know of, is set to QNH. I accept a radalt won't stop you flying into a cliff if you're intent on doing so.

Other than that I can't follow your logic. Sure, a QFE could be used as you describe. But so could a QNH without the requirement of being the same level. And this would also give your level relative to any spot ht (or cliff top!) on your chart.

[walter kennedy]

<< The baro alt, with no exceptions that I know of, is set to QNH.>>
It is indeed a requirement that it is set to QNH when low flying en route, the exception being when you are imminently approaching a point at which you want to land or pass closely, then you may have the QFE set.
One of the settings was for the correct QNH but the other was appropriate for a QFE at the point in question.

[ShotOne]

I don't entirely follow that, Walter but in my sentence that you quoted I was referring to low-vis (CAT 2/3)approaches.

[AOJM]

Why don't we all just use QFE for accuracy when looking to land. :D

[deltahotel]

ShotOne. Not sure the RAF does a lot of low-vis approaches. Ssuspect the post referred to poor wx/low ceiling/less than ideal vis rather than the formally defined cat 2/3.