altimeter setting

[Ulster]

Have just seen tonight's TV weather forecast. Storm force winds and heavy rain over the Christmas period. But what caught my eye, from an aviation point of view, was the pressure in the "low" just to the north of the UK - it was 930 mB !

It got me thinking, can an altimeter scale be wound down that far ? And, if not, what setting would one use (as if anyone would want to be flying in that kind of stuff anyway ! ) ?

Anyone any thoughts on this ? :ok:

[Dave Wilson]

I think most alts go down to 950mb (ooh sorry EASA, hectopascals). 930, bloody hell that is low. One of the reasons we should fly on QNH IMO and dump QFE altogether.

[Ulster]

930, bloody hell that is low

My reaction exactly, which is why I thought I'd ask !

One of the Met men said that the lowest pressure ever recorded over UK land was 925 mB ( the 930 was over the ocean) , and they were expecting it to drop later tonight to 927 mB !:=

[Talkdownman]

Dust off the QNEs!

[Dave Wilson]

I would be expecting a slight breeze over your way then...:)

If you think about it, 930 is 83 hecto thingies below standard atmosphere, that by my rough maths is around 2,300' difference. You would have to get the performance charts out if you were thinking of flying in that.

[Bob Viking]

Dave Wilson.
There are a few good reasons why we could ditch QFE but with most of our airfields close to sea level it won't make much difference what you call it. QFE or QNH you'll still have to wind the knob down to 930.

[Dave Wilson]

Indeed Bob (well you couldn't wind it down to 930 I think) I agree. What would you actually do then in that circumstance, maybe wind it down to the nearest thousand and subtract it? I think I would just add on another 35 hp's and call 1,000' sea level.

As an aside the highest airfield I visit in UK is around 825' ASL (Crosland Moor at Huddersfield) so you would have to wind down another 30 hps to get QFE for that field. IE have an altimeter that spun down to around 900 hps or less.

[Bob Viking]

In my current jet the scale goes down to 850. I guess when they designed that particular altimeter they researched the lowest recorded altimeter setting and subtracted a healthy margin to be on the safe side. I'm surprised that anyone would design one that only went to 950. Lazy or foolish. You decide.

[Dave Wilson]

I'm intrigued now. I'm off to the club tomorrow and will wind one down and report. Maybe you're right they go down to 850 and not 950.

[Genghis the Engineer]

I had one that would go down to 850 but most, in my experience, won't.

That's our third big storm this year isn't it. We could start to feel a bit got at.

G

[18greens]

The whole question is totally academic since no one will fly with a pressure setting lower than 950. Your sole worry will be how to stop the hangar doors taking off.

[piperboy84]

The whole question is totally academic since no one will fly with a pressure setting lower than 950. Your sole worry will be how to stop the hangar doors taking off

Funny you say that, I was overseas when we had the gales a few weeks ago left the plane in the hangar which has no doors with a west facing opening of 40ft wide by 15 hight, the east side has a door thats 10 ft by 12 feet which was destroyed by the wind blowing thru the shed, with the runners all bent and sheet blown 500ft across the field, funny (lucky) thing is the plane was parked without brakes or chalks facing the opening and never moved an inch, how'd that happen???

[Dave Wilson]

Flat plate of the door effect? I used to be able to do those sort of calcs, probably still could but I would put it down to that. You would be surprised how much pressure hangar doors have to put up with as opposed to an a/c which is designed to have blowy stuff passing over it.

[dubbleyew eight]

out of curiosity I wound back a smiths altimeter I have here as a spare.
800mb was that instrument's lowest full setting.
I think you'll survive.

[xrayalpha]

Here at Strathaven, we are 847ft above sea level.

It is not unheard of to be able to fly microlights when the pressure is low enough that you cannot set QFE. I have seen some fantastic low pressure flying days (maybe we were in the eye of the storm!)

I understand that, in the past at least, Loganair were once stuck in the Orkneys because they were unable to set QNH on their altimeters.

After a 24 hour delay, they got permission to set them 1,000ft out, and then correct once in the cruise.

For those who don't fly commercial ops, its an easy fix.

[FantomZorbin]

Xrayalpha
IMHO that's wot QNE is all about, strange Loganair didn't use it.

[Talkdownman]

Definition of QNE - Landing altimeter reading when subscale set 1013.2 hPa.

See CAP413:
Landing Altimeter Setting (QNE)
6.65
QNE is the indication which the altimeter will give on landing, at a particular time and place, when the hectopascal scale is set to 1013.2 hPa.
QNE information may be used by pilots of aircraft whose altimeters cannot be set to below 950 hPa.
The QFE/QNE conversion will be calculated by ATC.
Example: QFE 947.6 Set 1013.2 on altimeter.
Altimeter will read 1842 ft on touchdown hectopascals
The QNE tables are in MATS Part 1 Appendix A Page 2, and were available long before Loganair was ever thought of.

For example, if the Strathaven QFE is 945 hPa then the Strathaven QNE is 1917 ft.

Easy… ;)

[Dave Wilson]

Checked our 182 this afternoon it goes down to 955, however you can still keep winding it down after that although there's not much point as you don't know what it's set to.

[BackPacker]

So, essentially, QNE is the Flight Level at which your wheels touch the tarmac, right?

(Obviously it won't be a *usable* Flight Level, as it'll be below the Transition Layer, but I just want to check I've got the concept right.)

[Talkdownman]

Sort of. But try not to think of it as such. QNE is the reading on the altimeter on landing with the subscale set 1013.2 hPa. In the Strathaven example you would be rounding out at 'FL19'. But best not to think of flight levels existing below the Transition Altitude. All you are looking for is, say, flying a circuit at approx 2900ft, final at approx 2400ft, landing at 1917ft etc. Needs special care in IMC! Use a RadAlt if you've got one…

Try it out in low pressure in VMC. The tables start at 979 hPa falling, so you should have at least 29 hPa or so to play with to set a real QFE on a second altimeter for comparison until you run out of subscale.

[BackPacker]

And is this a typical UK thing, or are controllers anywhere in the world supposed to give me the QNE when I ask for it?

[Dave Wilson]

I can tell you what QNE is; 1013.25 hectopascals. Thought you would have known that...:)

[Talkdownman]

Aw, Dave, QNE is a level, not a pressure setting. Thought you would have known that… :) (Was my instructing at EGLF wasted… ;) )

[Crash one]

So what is the calculation/formula please? 1013.2 - QNH X 30ft + elevation? Serious question by the way!

[Dave Wilson]

Aw, Dave, QNE is a level, not a pressure setting. Thought you would have known that… http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif

I am confused now, which I must confess is easily done.

[hegemon88]

OK, I'll tell everyone what I've understood. Unlike QNH and QFE which are altimeter settings, QNE is an altimeter reading - it is an indication on your altimeter at landing when you set it to 1013.2/29.92. Of course it is as changeable as QNH and QFE, so you need to get it each time from someone. And then, when landing:

instead of setting QNH on alt and reading THR elev when you land, and
instead of setting QFE on alt and reading 0 when you land,
you set standard setting 1013.2 and read QNE when you land.
Did I get it right?


To answer a question from Crash one I'll now put my Math MSc hat on:

I just derived on the back of an envelope that QNE = (1013.2 - QFE) x 30, but:
QFE = QNH - (elevation/30), so:
QNE = (1013.2 - QNH) x 30 + elevation
Quod Erat Demonstrandum :cool: You just missed brackets :E


/h88

[Crash one]

Thank you I did remember the brackets but too late. Must try harder !!

Therefore: Leuchars QNH at this time is 958hectobars. If I were to land at Kingsmuir, elevation 398 ft altimeter should read 2114ft (using what should have been QNH) ?

[Talkdownman]

Please refer to CAP493 (http://www.caa.co.uk/docs/33/CAP%20493%20MATS%20edition%205%20amendment%201.pdf) Annex A Page 2.

Crash one, you would need to obtain/calculate/deduce a QFE for Kingsmuir. If using the Leuchars QNH then the Kingsmuir QFE might be approximately 14 hPa lower, ie. approximately 944 hPa, and possibly off the subscale. From the table QFE 944 hPa gives a QNE of 1946 ft, ie. the altimeter would indicate approximately 1946 ft on landing.

OK, I'll tell everyone what I've understood. Unlike QNH and QFE which are altimeter settings, QNE is an altimeter reading - it is an indication on your altimeter at landing when you set it to 1013.2/29.92. Of course it is as changeable as QNH and QFE, so you need to get it each time from someone. And then, when landing:
instead of setting QNH on alt and reading THR elev when you land, and
instead of setting QFE on alt and reading 0 when you land,
you set standard setting 1013.2 and read QNE when you land.
Did I get it right?

Correct.

Dave, a QNE is not a pressure setting. If you are the Dave Wilson I trained at Farnborough in the early eighties you have since become a very experienced GA pilot, so should therefore know this!

[Dave Wilson]

That's the second time in about an hour I've been mistaken for someone else in two different threads! I'm Dave Wilson of no fame whatsoever. It's a very common name believe it or not. In fact my full name is David John Wilson and there was anothe DJW of the same rank on 3Sqdn when I was there. Caused no amount of hilarity. The chap on the other thread thinks I am one Whizz Wilson of Australia.

Me. Not to be confused with more famous Dave Wilsons.

http://i1081.photobucket.com/albums/j355/thing56/11fee9b5-0157-4d07-ab0f-2d04c9069a32_zps26c330b4.jpg (http://s1081.photobucket.com/user/thing56/media/11fee9b5-0157-4d07-ab0f-2d04c9069a32_zps26c330b4.jpg.html)

So if I'm asked to set QNE when flying IFR exactly what pressure setting do I set on the subscale? Have I been flying at the wrong FL all this time?

[Talkdownman]

Mis-ident. Us ATCOs do that occasionally. Use full callsign.

Anyway, he was better-looking than you. Probably because of that sprout soup, it doesn't look very appetising.

1013.2 hPa. It's not a QNH, not a QFE, nor a QNE. it's SPS.

Greetings to all in Season.

[Dave Wilson]

At risk of sounding stupid, no I'll rephrase, sounding stupid, exactly what is QNE? I've been flying all of this time, IFR and VFR and not known what it is. Methinks there was a gap in my training somewhere.

[Talkdownman]

From CAP413 (http://www.caa.co.uk/docs/33/CAP41320Editionto4April2013_ISBN9780117928206.pdf):

QNE is the indication which the altimeter will give on landing, at a particular time and place, when the hectopascal scale is set to 1013.2 hPa.
QNE information may be used by pilots of aircraft whose altimeters cannot be set to below 950 hPa.
The QFE/QNE conversion will be calculated by ATC.

:ugh:

Clocks off… :zzz:

[Dave Wilson]

Ah, got it now. I thought you were saying QNE wasn't 1013.25.

I know it's not, I know what you mean by it's not 1013.25. But it is in the backwards way I'm looking at it. We are all clear now, just a syntax problem.

Probably because of that sprout soup, it doesn't look very appetising.


It's actually snails in garlic during a visit to Le Touquet earlier this year. Wouldn't recommend but tick in the box and all that.

[Jim59]

See CAP 493 and search for QNE or go to the 342nd page. There is a table for ATC staff to convert a QFE to a QNE when QFE is between 970 and 900. Value is the reading on an altimeter set to SPS.

[tmmorris]

I once had the altimeter knob come off on approach to Oxford - I got the ATIS, found I couldn't set the QNH (I'd been on regional pressure so quite a few mB different), switched to Approach, informed them, and could hear quite clearly even from 10 miles or so out the scratching of heads as they tried to work out the circuit indicated altitude I should fly to put me at 1200ft QNH.

To be fair to them, it only took them about 30 seconds to come back with an answer which I think was correct (seemed to work, anyway!).

[Dave Wilson]

The other thing to watch out for is taking off from a high airfield underneath airspace with QFE set. Crosland Moor at Huddersfield is a good one for that, there's class A at 3,500 and class D at 3,000. Field is at 800 odd feet, easy to forget on the climb out, seen it happen.

[fireflybob]

Just for the record a millibar change on the altimeter sub scale is worth 27.3 feet - 30 feet is an approximation

[Dave Wilson]

Doesn't that decrease as you go up?

[fireflybob]

Yes the formula is h=96T/P where h is foot per mb, T is Absolute Temp (deg C + 273) and P is pressure in mb.

However to work out QNE imagine you are on ground at an airport which is 1,000 ft amsl and the QNH is 963 mb so with 963 set the altimeter indicates 1,000 ft Now set 1013 - you are winding on 50 mb = 50 X 27.3 = 1365 ft The altimeter now reads 1,000+1365 = 2365 ft so this is QNE.

I stand to be corrected on this one but although the height change per mb changes with temp and pressure the change in indicated altitude will be the same for a given change in sub scale setting at different altitudes.

[Discorde]

The other thing to watch out for is taking off from a high airfield underneath airspace with QFE set. Crosland Moor at Huddersfield is a good one for that, there's class A at 3,500 and class D at 3,000. Field is at 800 odd feet, easy to forget on the climb out, seen it happen.

The answer to this problem is to discontinue use of QFE, as previously discussed in this thread (http://www.pprune.org/private-flying/368781-qfe-who-needs-regional-altimeter-setting-ditto.html).

[Dave Wilson]

Couldn't agree more (see post #2). It would be nice to have approach plates with just one setting on.

[Crash one]

Quote:
The other thing to watch out for is taking off from a high airfield underneath airspace with QFE set. Crosland Moor at Huddersfield is a good one for that, there's class A at 3,500 and class D at 3,000. Field is at 800 odd feet, easy to forget on the climb out, seen it happen.
The answer to this problem is to discontinue use of QFE, as previously discussed in this thread (http://www.pprune.org/private-flying/368781-qfe-who-needs-regional-altimeter-setting-ditto.html).

Which is why I would prefer, in the case of QNE to not bother with the added calculation of QFE. That way a single QNH derived alt reading would do for anywhere & the pilot can add elevation as required.

[On Track]

This is yet another thread that convinces me the British make everything in aviation unnecessarily complicated.

We get by perfectly well with just QNH (aerodrome QNH or area QNH) and 1013, and most light aircraft never have to bother with the latter.

[Shoestring Flyer]

No... QFE is good!...I use it always, I like it. Doing mental arithmatic in the air whilst landing an aircraft is not for me!

[Andy H]

I use QFE when flying near my base airstrip - that way I don't suffer a CFIT if the weather clags up. As a UK pilot I have an Airspace Aware unit that gives me a (gps derived) QNH so I have belt and braces! Not that QNH is of any use whatsoever as I NEVER go near controlled airspace....
Andy

[Dave Wilson]

How would having QFE set stop you from having a CFIT? Surely QNH does a better job?

[fireflybob]

The QFE/QNH debate is as old as aviation itself!

If you've only ever operated QFE you think QNH operation is like going to the moon.

Having operated both over 40 years of flying I know which I prefer and what I think is safer and that's QNH every time.

[Shoestring Flyer]

It is generally flatland southerners who want to get rid of QFE because of the minimal difference between QNH and QFE from where they fly from/to. If they came north occasionally where airfields/airstrips are at higher altitude than sea level the novelty of doing mental arithmatic when coming in to land would soon wear thin I think.

[fireflybob]

If they came north occasionally where airfields/airstrips are at higher altitude than sea level the novelty of doing mental arithmatic when coming in to land would soon wear thin I think.

Good grief - how do they manage in other countries where there are far more higher terrain airfields than in the UK? Ever tried to set QFE at Nairobi?

[OhNoCB]

While I try not to tell people whch way to do something, because it is their own preference, I simply do not understand a couple of the points made about QFE in the last few posts.

How does QFE stop you having a CFIT?

What is the mental arithmetic required during landing if using a QNH even if into higher elevation fields? I spent some time flying light aircraft around Portugal which I only mention because they have field elevations at and around 2000' in places which is more than you get in the UK, and I never remember doing any mental calcs.

[Discorde]

Perhaps a new trend could be set by not including QFE in RT transmissions for those that preferred not to use it. If challenged for non-read back, state - politely - 'using QNH and field elevation'. If passed a RPS, your response could be 'using local QNH'. (Plus optional 'thank you').

[Dave Wilson]

Having said and read all, unless you are making an approach in clag or somewhere where the circuit is busy and need to stick to a circuit height why do you need to look at the altimeter when making a landing? Surely it's all visual clues with the odd glance at the ASI. It doesn't matter what the field elevation is, just use your eyeballs.

Tin hat donned...:)

[Crash one]

"If they came north occasionally" I love it! I can't be bothered to set QFE much of the time, it's easier to just add the known elevation to the usually round thousands of circuit heights, hardly mental arithmetic.

[Shoestring Flyer]

Well if QFE is good enough for the RAF it is sure good enough for me..

Incidently I was once failed on an IMC test for not setting QFE!

Seriously though I admit it was the way I was taught way back in the early eighties to always use. I now cannot see me using anything else. I don't give a stuff what ATC tell me QNH or QFE, regardless I will always use QFE. To me it is just logical...set pressure to give me the altimeter reading zero when I touch down on the threshhold, just tell me what could be simpler!

[Bob Viking]

If I may interject I would like to profer my opinion? As an RAF pilot with 14 years FJ experience I can see both sides of the argument. In the UK I would much rather use QFE because it is easier in my mind. I am currently based in Canada and in the last year have flown approaches into Boulder CO, Great Falls MT, Casper WY, Salt-lake City UT (I'll stop there or it just looks like bragging) and QFE would make absolutely no sense whatsoever (as discussed here it would be far outside the range of pretty much every altimeter on the market).
In my experience UK civvy airports will give QNH unless you ask for QFE. This arrangement works just fine for me and appears to be the best of both worlds.
I am pretty happy with either. I think the maths that Dave Wilson may be talking about is the need to add circuit height or DH to runway elevation.
BV

[Dave Wilson]

Maths? Didn't realise I'd mentioned it. Because I fly from a mil field it's QFE on the instrument approaches, if I do an approach at Donny up the road it's QNH. I just think that even if they don't bin QFE altogether they could at least make approach plates standard and use QNH on all of them. I know that both QFE and QNH are on the same plate but why confuse the issue when there's no need?

As I said earlier once you're in the circuit you don't need the altimeter anymore, or shouldn't do at any rate.

[phiggsbroadband]

Well just flipping through my Pooleys, I see that most UK airfields are below 200ft asl. With only a few over 400ft asl. So it is not too much strain to wind on 10 hPa on the dial from QFE to QNH.


btw. I have a spare ex Air Ministry Altimeter that goes down to 800 mB (~6000ft) on the subscale.

[octavian]

Three interesting posts from Shoestring Flyer.

Post 45: QFE may be good for you when landing and in the vicinity of the aerodrome (circuit), however once you move away from those environs do bear in mind that the base of controlled airspace, where defined as an altitude, is based on the relevant QNH. Head away from your airfield on QFE and (in pretty much all of the UK) you will already be x feet above sea level. This may cause you difficulty, because you are now flying at a height, which may put you close to or even above the base of CAS (altitude) of which you may not be conscious, because you are flying on QFE. Or do you do the relevant mental arithmetic whilst flying to prevent an inadvertent infringement.

Post 49: At peril of engaging in a north-south, hills-flatlands and QFE-QNH debate, to which others have alluded, I find it remarkable that pretty well all commercial operators, including single pilot operators, use QNH and manage the mental arithmetic involved. I would suggest that adding the elevation of your landing strip to the relevant QNH and then flying it accurately should be well within the competence of any qualified pilot; it is, after all, simple mental arithmetic.

Post 55: Regarding the RAF; sadly, it is a somewhat minor player in aviation these days and it's historic adherence to QFE is not reflected by the major players - the airlines, whose use of QNH is pretty much total. To that end all professional flight training operators will use QNH as part of the process of preparing their students for commercial operations.

It is also worth considering that all UK civil ATC units will use QNH as the basis for providing the vertical separation of aircraft under their control, and are unlikely to make adjustments for the personal preferences of pilots who don't give a stuff what ATC say. Even if you request and are given a QFE, in addition to the airfield QNH, you will be expected to state your vertical position by reference to the QNH, as an altitude.

Fly safely, and do bear in mind that the charts mark elevation related to sea level.

[Silvaire1]

Wouldn't it be nice if there was only one altimeter setting... You could call it 'altimeter setting' :) All the terrain on the chart including the airport elevation would match the altimeter. All airspace delineations would match the altimeter at all times. Every plane of interest would be on the same setting, and would be individually responsible for keeping their altimeter accurate using widespread sources of airborne aeronautical data. Eventually you'd have a difficult time finding a pilot who would know what Q-this and Q-that meant, because it would be archaic nonsense.

It doesn't hurt to dream ;)

[Crash one]

Do people actually fly cross country on QFE? I was under the impression it was only used in the vicinity/circuit? It is all the twiddling that is the problem, isn't it?

[Prop swinger]

* inane wibble *If you don't like QFE, don't use it. How hard is that?

It's just another option, there's no requirement to use it VFR (don't know about IFR rules.) I've never understood why people bother to moan about QFE.

[Silvaire1]

Prop swinger - I was describing the existing situation in the US, where most GA worldwide occurs and where the mention of Q-anything would gather only a blank stare, or perhaps a gentle smile of recognition in recalling Q-codes as a long obsolete and slightly bizarre concept from the history books, right next to Morse code as primary communication. QNH is called by that name today (in some places) only as a necessity created by those, mainly in the UK, who refuse to let go of the Edwardian past, including its arcane and today pointless navigation practices.

Given widely available altimeter data, it is normal worldwide practice for all low altitude GA aircraft to use a common type of altimeter setting that tells each of them how high they are above sea level. Accordingly, most pilots worldwide don't have any need to understand Q-codes; most of the world wouldn't know what QFE means and for God's sake of course I'll never use it!! :ugh: :rolleyes:

[2 sheds]

I think that you will find, Silvaire, that despite your parochial outlook to the contrary, both QNH and QFE are terms both of description and in RTF phraseology used by ICAO, i.e. recognised world-wide.

2 s

[Desert185]

Apparently the Dave Wilson of Soylent Green fame. :O

[Desert185]

I think that you will find, Silvaire, that despite your parochial outlook to the contrary, both QNH and QFE are terms both of description and in RTF phraseology used by ICAO, i.e. recognised world-wide.


If anyone has a parochial attitude about aviation its ICAO.

[2 sheds]

If anyone has a parochial attitude about aviation its ICAO.

Explain, please, in this context.

2 s

[Desert185]

shoestringflyer
It is generally flatland southerners who want to get rid of QFE because of the minimal difference between QNH and QFE from where they fly from/to. If they came north occasionally where airfields/airstrips are at higher altitude than sea level the novelty of doing mental arithmatic when coming in to land would soon wear thin I think.


I live and fly in the mountains where homebase elevation is 5400'. QNH for me, please, and yes, I have tried QFE when out of the country. I don't like it.

American Airlines used QFE for years with another altimeter set to QNH below FL180 or the Transition Level elsewhere. Talk about confusing mental arithmetic...but if its your cuppa tea...

Quote:
If anyone has a parochial attitude about aviation its ICAO.
Explain, please, in this context.

2 s

Sorry, if I have to explain that you wouldn't understand.

[fireflybob]

Recall going into Crete one day in the 1980s about number 5 or so in the sequence to join right base visual for the westerly runway. Greek controller working like a one armed paper hanger with departures as well (same track).

In the middle of the RT fracas Danair ahead of us calls up requesting the QFE - a rather exasperated controller replied "Danair XXX the QFE is five millibars less than the QNH".

Wouldn't it be nice if there was only one altimeter setting... You could call it 'altimeter setting' All the terrain on the chart including the airport elevation would match the altimeter. All airspace delineations would match the altimeter at all times. Every plane of interest would be on the same setting, and would be individually responsible for keeping their altimeter accurate using widespread sources of airborne aeronautical data. Eventually you'd have a difficult time finding a pilot who would know what Q-this and Q-that meant, because it would be archaic nonsense.

Silvaire1 - love the irony and am with you all the way.

In the days when we operated QFE you could almost take a £5 bet on seeing an altitude bust in the event of a missed approach in the simulator. As soon as we changed to QNH it became a rarity.

[On Track]

It's certainly not true to say that QFE is used or even understood worldwide.

I'd be interested to know which countries, other than Britain, use it at all.

[Dave Gittins]

Having just returned from a fabulous Christmas holiday flying in Colorado and Florida, I concur that any expression starting with a "Q" is unlikely to be met with a full and complete understanding in the continental US. The words that get the correct answer are "altimeter setting".

The highest field I flew into was Buena Vista at elv. 7,950', (sadly I missed Leadville 43 miles further up the valley where the pattern is flown at 10,700') and the lowest was Everglades at about 6'.

Reading the Denver sectional and using QFE are two things not to be done together and I made copious kneeboard notes before I set off of the airfield elevs and pattern altitudes I was going to encounter. The changes in altimeter setting over relatively short distances surprised me.

The same principle of using QNH easily translates into my normal flying in SE England with Redhill at 222 ft.

[Desert185]

Dave Gittins
The changes in altimeter setting over relatively short distances surprised me.

One of the reasons the mountains make their own weather, and also destroying the practice of always flying a known pattern altitude and a set power abeam the threshold for the descent to touchdown. Remote mountain airports don't always broadcast field altimeter settings. Just a few of the variables that make mountain flying so interesting and enjoyable.

Try the Frank Church River of No Return Wilderness area in Idaho next time. An example airport: Wilson Bar (C48) requires a two mile flight upstream in a narrow canyon to reverse course downstream for a low and slow, last minute dogleg turn to a one way final with no go around at no more than 100' above the river. Field elevation 2275', runway length 1500', gravel/grass/snakes. :ok: