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Rocky38
14th Jun 2003, 12:08
Although I'm familiar with the physics of Qfe vs. Qnh baro setting, I have never flown in an environment where Qfe is used as a matter of course. Does any regular Qfe user care to comment how it is used procedurally?

Is it only set on the PF or the PNF altimeter? Is it only set on altimeter #2? #1?

Is it used during departure as well as descent/approach?

Is it used for all of the descent below the transition level, or only in the approach environment?

If a given carrier uses Qfe, is it used at all destinations, or only at those destinations where the Qfe pressure is given on the ATIS? If used at airports where the field pressure is not given on ATIS, how is the appropriate baro setting determined?

Is Qfe operation required in certain countries?

Thanks -
Rocky38

BEagle
14th Jun 2003, 16:18
The UK assumption is that 'QFE will be set for descent from the final approach fix'. But in reality most airports will permit either QFE or QNH to be used. The advantage of QFE lies in knowing your HAT at all times - particularly useful inaeroplanes without rad alts!

Personally I prefer QFE in the aerodrome visual circuit and on the descent from the final approach fix - but levelling off at a missed approach altitude in the pattern after a late go-around will require the altimeter subscale to be reset when you might have both hands full of aeroplane!

Genghis the Engineer
14th Jun 2003, 18:35
QFE is the norm here in the UK, but the only fields where you'd be dissallowed from flying QNH would be RAF and Army airfields, the Navy uses QNH as a matter of course and whilst all civil airfields will give QFE how you use it is generally commander's discretion.

Having said that, normal drill is to set QFE on primary (PH) altimeter either when instructed by the approach controller, or if flying a visual approach once you transfer to the approach controller.

If departing it's normal to set QNH from the start UNLESS remaining in the visual circuit, in which case you'd leave QFE on throughout.

If transitting an ATZ or MATZ in the UK, you'll normally also be asked to set QFE and given clearances relative to that. Normally other airspace transits will be done in QNH.

G

G-ALAN
14th Jun 2003, 19:01
In the UK we use QFE alot in light aircraft flying. When I enter the circut I always set the airfield QFE which will give you your height above the airfield. Most airfield circuts are flown somewhere around 1000ft agl so every aircraft in the circut has to have the airfield QFE set so they are all at the same level in the circut. I'm not sure how the big boys use QFE but thats how us Little Boys use it. Hope this helps :ok:

Tinstaafl
15th Jun 2003, 00:11
I don't use QFE at all and stick to QNH. The only time I've been given a QFE I requested & got a QNH. I find QFE to be a right pain in the @rse.

On Track
15th Jun 2003, 09:08
It's really simple in Oz.

We don't use QFE (although I think some glider pilots do).

Rocky38
15th Jun 2003, 09:11
Many thanks to all for the insight.

Over here in the USofA, use of Qfe is basically non-existent in the general aviation/corporate sector. I have heard that there is at least one scheduled carrier that uses Qfe regularly on one altimeter, but I don't know any details on how they use it.

Thanks again.

Cheers -
Rocky38
:ok:

India Four Two
15th Jun 2003, 10:41
In many parts of the Western US and Western Canada, the airfield elevations are too high to allow the use of QFE - there isn't enough sub-scale to allow you to wind the altimeter back to zero - I know, I've tried it at Calgary. I forget how far I could go, but it wasn't the full 3550'.

In a previous discussion on this topic, it was mentioned that American Airlines used to use QFE, but they had to have specially built altimeters

LEM
15th Jun 2003, 15:24
Interesting, I thought QFE had been banned almost everywhere some years ago.
It seems I was wrong.
I used QFE years ago, I remember everybody liked it, of course it gives instinctive HAT indications... and transitioning to QNH seemed to be quite difficult.
Today, using QFE would be almost unthinkable to me, for three (good) reasons:

1) there's an implicit and serious risk (which could be fatal) in such a practice: you have to calculate your QFE by substracting tot hectopascals from QNH.
If you make a mistake in calculating it, how can you have a good glide check? are you sure you are going to decide, at the minima, before hitting the ground?

We used to seek some confirmation from the radioaltimeter, setting DH on it, but that was not good practice, since radioalt is allowed only for Cat II&III.

2) As already noted, you can't use QFE on elevated airfields, because of the lack of subscale...

3)Today everybody works with FMS's, and I think all FMS's altitudes are QNH and can't be turned into QFE.

That said, it's interesting to hear that I might be required to use it again, if I had to fly to the East....

eastern wiseguy
15th Jun 2003, 17:27
As an ATCO in the uk I find that the majority of light aircraft will use QFE for final aproach and landing as a matter of course.As to the QFE being "banned" that is news to me we have four runways each with its' own elevation...so I expect you meant to say USE of QFE :) .During the night when we have the majority of our freight traffic the older aircraft all use the QFE and in fact request it upon first contact.As to whether or not it is a "better" system I as an ATCO care little...I am happy to base approaches such as surveillance radar approaches on either pressure(for me there is no mental gymnastics just a different set of figures to refer to)although the QFE figures are standard and are VERY easily memorised.All I ask is that in the event of a go around the correct levels are flown ..and as Beags says that might lead to confusion if you have a handful of big jet!(as an aside Beags did not the boys in blue go back to QNH to prevent problems caused by switching from one setting to the other as it was deemed a distraction for single seaters?)

Tinstaafl
15th Jun 2003, 19:40
I prefer QNH because charted elevations are MSL referenced. I want to know how clear I am of such things. QFE only gives a single reference point ie the threshold.

Also QNH avoids having to change in the missed approach & allows ready comparison to nearby traffic that isn't landing at the aerodrome (so not using QFE).

LEM
16th Jun 2003, 16:22
...so I expect you meant to say USE of QFE
Of course.


Just curious, does Big Airways use QFE? Thanks :confused:

HotDog
16th Jun 2003, 16:37
We never have and I don't know of any commercial carrier using QFE.

By the way LEM, you have now answered my puerile question.
Cheers, HD.

LEM
16th Jun 2003, 17:57
I'm sure this makes you fell bigger and better! :p

fireflybob
16th Jun 2003, 19:12
Ah the QFE/QNH debate - almost as old as aviation itself!

The insularity of the British (shades of empire perhaps) who love their QFE! Have used boths systems and I know which I prefer - QNH every time! That said so long as you understand and apply the system you use there is never a problem.

Remember well going into Heraklion (Crete) on a beautiful summers day. ATC working like a one armed paper hanger coordinating the inbound and outbounds (same departure/arrival track). In the middle of the RT mayhem DanAir asks for the QFE - exasperated Greek controller replies - "Danair the QFE is five millibars less than the QNH!!"

Captain Stable
16th Jun 2003, 21:30
Actually ffb, you will find (try reading back through the thread) that most Brits prefer QNH, and that it is the Americans and various other countries where QFE is preferred - generally for vaey good reasons, and nothing to do with insularity at all.

fireflybob
16th Jun 2003, 23:00
Captain Stable, well, yes I got carried a way with the vernacular there but it's the Brits Military and civil flying schools that mostly (in the UK) go down the QFE route.

I agree though that most Air Transport Operators (in the UK, anyway) use QNH. The DanAir story which I related took place at a time when most UK operators were still using QFE.

Genghis the Engineer
16th Jun 2003, 23:30
I agree with Bob, QFE is a useful term in most aspects of light aviation operations in a relatively low-lying country - but not necessarily so for air transport operations, or where threshold elevations are routinely more than around 1500 ft amsl.

I suspect the British preference for QFE is because we have no airfields above 1000ft amsl - so we can get away with it !

G

TR4A
17th Jun 2003, 02:32
Actually ffb, you will find (try reading back through the thread) that most Brits prefer QNH, and that it is the Americans and various other countries where QFE is preferred - generally for very good reasons, and nothing to do with insularity at all.

The only "Americans" that I know of was American Airlines. They stopped using QFE a couple of years ago.

Notso Fantastic
17th Jun 2003, 03:53
Big Airways now never touches QFE. I remember going into Addis Ababa in the old days trying to wind 8,000' worth of subscale setting on for QFE. It took each pilot out for several minutes. What is it good for? When you are in the circuit, you want to know
1-how high you are (amsl)
2-how high the terrain is (amsl)
3-how high the airfield is (amsl)

Armed with that lot, you've cracked it. Wander out of the circuit with an altimeter set to QFE and it isn't really telling you much anymore. QFE should be banned- there is no place for it in modern aviation.

reynoldsno1
17th Jun 2003, 05:53
As previously mentioned, QFE is not very useful at higher elevations and can be a distraction. I believe UK manufactured altimeters actually have a wider pressure subscale range than US manufactured instruments

Genghis the Engineer
17th Jun 2003, 20:49
I have a German made altimeter (broken) in use as a paperweight whose subscale goes down to 750hPa ! That should be good to about 7000 ft.

Incidentally I once had occasion to file an airprox, which was flying nonradio in a little puddlejumper just-off the West Scottish coast. I listed my altitude at 900 ft QNH. A few weeks later I had a call from the Airprox board, and the conversation went something like this...

"You list your altitude as 900ft QNH"
"That's correct"
"What setting did you have on your altimeter"
"I don't know, I didn't take a note of it".
"Then how do you know it was set to QNH?"
"Because I set it to zero just before taking off from the beach halfway between the low and high tide marks".

<long pause>

"Err, there may be something wrong with that, but I'm not sure - I'll get back to you".

And he never did :O

G