[TopCat]

There's this thing called 'Exercise 14'

Correct so far.

It only ever happens once

Still correct.

It only takes about 14 minutes

Still correct.

It gives you the best high in the known universe.

This is absolutely incorrect if you make a dumb mistake during the exercise that remains with you for ever (albeit with gradually decreasing levels of embarrassment) even if no actual harm was done, and the learning from that dumb mistake probably saved your life many times over the next 30 years.

Yes it's worth it.

Ah, well, I'd agree with that.

[Kemble Pitts]

This is absolutely incorrect if you make a dumb mistake during the exercise that remains with you for ever (albeit with gradually decreasing levels of embarrassment) even if no actual harm was done, and the learning from that dumb mistake probably saved your life many times over the next 30 years.

Yes it's worth it.

Ah, well, I'd agree with that.

Go on Mr Cat, we are all ears...

[Rob P]

I've fessed up to the Abbeville taxiway. Definitely need to hear the Ex 14 story now.

Thank you Rob, I`m sorry if I sometimes annoy you when I write something which when I think about it later is obviously completely wrong.

I am impossible to annoy, so fret not.

I was wondering what prompted this thought. Looking back I suspect you thought that my post here viewtopic.php?p=1819362#p1819362 was aimed at you? Trust me, it wasn't.

Even thirty years on I can recall how difficult it all looked from the student point of view. I sometimes thought I would never make a decent pilot. Looking back now, I can see I was right.

Rob P

[malcolmfrost]

I wonder how much they spend above Transition level! Set QNH before taxi and chances are you won't need to change by more than a couple of mb ! So! Going off this statement, it sounds like you set QFE while you`re flying because you don't go above the Altitude Level and obviously don't cruise in the transition level, have I got that right?

Sorry Ian, I think many of us forget what it was like at the very start! I've been doing this for 50 years and haven't stopped learning yet! Ignore us!!

[TopCat]

I've fessed up to the Abbeville taxiway. Definitely need to hear the Ex 14 story now.

Pretty sure I've posted it before, but sure...

On that morning, I'd flown a couple of good circuits. Instructor says, "taxy over to the tower", so I do. When we get there, he unclips his seatbelt, pulls the throttle to idle, pulls the canopy open, says "I'm going to send you on your own now. Do as many circuits as you like."

And hops out, leaving me somewhat poleaxed. Even though you know that first solo must be getting close, it's still a shock when it happens.

So I did all the checks, lined up, took off, all good. Noted amazing rate of climb. Flew an absolutely perfect circuit. Touchdown light as a feather. Power on for touch and go... rolling..... "Hmm. Ground feels a little rougher than normal, ah well, here we go", and I was back in the air.

Then, over the radio, from the next aircraft on final...

"Goodwood, G-XX, can you confirm the last aircraft actually landed on the strip of grass parallel to the runway?

"G-XX affirm, I'll be having a word with him in a moment."

Cheeks burning, I realised immediately why the grass had felt a bit rough. There was a bright yellow, runway-width strip of freshly mown grass right next to the runway, and I'd locked on to it visually on final, and once locked on, just concentrated on the landing. The fact that it had no numbers or marker boards didn't cross my mind....

Anyway, it was absolutely mortifying. I was all over the place for that second circuit, and it only got worse when I called downwind and got a very friendly lecture on marker boards, numbers, and how to distinguish the long runway from the parallel (on the other side) short one. As if I hadn't been landing on it for weeks....

My second landing was a bit of an arrival, albeit on the runway this time, but I was determined not to give up. So I climbed away for a third one. I was recovering from the extreme embarrassment by then, so the third one went fine, at which point I thought I'd quit while I was ahead.

I shut down and got out, and my instructor was walking across towards me. Thankfully he was grinning. We went and had some lunch, talked over the mindfart, and then he said....

"Ok, go and do another hour of that on your own."

So I did.

Anyway, I really did learn about flying from that.

Check. Check again. Assume you're a muppet, and that you've misidentified something... mistuned a frequency... forgotten the circuit direction... forgotten some checks.... whatever.

Take nothing for granted in aviation.

[akg1486]

Check. Check again. Assume you're a muppet, and that you've misidentified something... mistuned a frequency... forgotten the circuit direction... forgotten some checks.... whatever.

It's now eighteen years since I started learning and after some 5-600 hours I can confirm that this is very good advice indeed.

I landed at an uncontrolled grass strip last year when there was nobody in the circuit; this is a place I had been to many times before. I managed to read the windsock correctly, picked the correct direction and made positional calls on downwind, base and final. In the club house, someone who had been listening on the radio said to me "by the way, you landed runway 30 but you called out 12 all the time." I definitely felt like a muppet.

Since then, I'm checking the runway orientation twice. If I'm in an aircraft where the gyro has a heading bug, I set that.

[Rob P]

Love the story TC.

I have managed to join you in that club also. Landing on a strip of grass adjacent to the actual strip because of the way the mowing had been done. As the prop started chopping through tall grasses I just knew something had gone wrong somewhere.

I am now trying to remember where it was.

I suspect it might have been 26 Grass at Kemble.

Rob P

[Paul_Sengupta]

While we're on wrong runway confessions, I once pulled up to the holding point where both 03 and 05 begin at Sywell. I called departing 05 and promptly took off on 03.

[T6Harvard]

I hope Ian won't mind me jumping on his thread with a supplementary question?

I am very very low hours, widely spaced due covid and any questions I have are no reflection on my instructor. As others have said we students just haven't had time to ask much lately.

I'd be very grateful if someone would clarify how I set the correct QFE as we return to the circuit.
This is my training scenario - We fly out on QNH as we are leaving the circuit and therefore need the alt to match the situation (as others explained, keeps me away from controlled airspace, gives correct terrain clearance, etc). On the runway the altimeter reads height AMSL and that is our double-check.
Runway is 450' AMSL.

Before rejoin we listen to the ATIS to obtain the latest QNH and then convert that to set QFE for circuit and landing.

NB, the ATIS is taken from nearby East Midlands airport because my airfield has no A/G during the week. This seems perfectly logical because it is close by and there are no peculiar geographic influences that will invalidate the figure. However, this is why I have a second question!

My questions are these:
1) When I hear the QNH, let's say 1002 hPa, am I correct to then calculate the lower pressure due to airfield elevation, deducting 1 hPa per 30', thus at a QNH of 1002, minus 15 hPa (450' ÷ 30' ) and set 987 hPa in the window?

And what is really bugging me....

2) Do I actually need to know the DIFFERENCE in altitude between where the QNH is measured and my airfield, rather than just deducing the full field elevation?
* scuttles off to find field elevation of East Mids* It is 306' AMSL.

(Apologies in advance if my maths is wrong. I have a reputation to keep up!)

[TopCat]

Love the story TC.

Thanks... it was a very long time before I could bear to tell it, but I don't care so much any more.

It doesn't irk me anywhere near as much as it used to, and I can see how it's been a real benefit over the years. The check, check again - and again, dammit - mantra has saved me from quite a few situations over the years. Not that I don't still make mistakes - of course I do - but my fear of looking like a plonker usually kicks in before I do anything bad enough to be dangerous.

The last idiot thing I did wasn't dangerous (although I could have done some expensive damage to the aeroplane) and I got away with it but I did write up a CHIRP report on it so hopefully some have already had the chance to learn from my f*ckwittery . I'll save that story for another time here though - it's still quite raw. Maybe in another 30 years

[akg1486]

If you feel you must set QFE when returning, the simplest is to turn the knob so the altimeter shows 450 feet less. If you’re bimbling along on, say, 2000 ft MSL (QNH set) you will be 2000-450=1550 feet above your airfield. Adjust the altimeter accordingly.

The alternative is to continue on QNH and mentally change the circuit altitude. If that’s 1000 feet GND (QFE), it will be 1000+450=1450 feet MSL.

[Charles Hunt]

Not going to answer those directly, but here are my thoughts.

Stick to QNH when possible, but if you get confused arriving somewhere, then dial in their QFE.

Why?

Travelling cross country (at bimbling heights) you want to be on QNH to avoid busting airspace or flying into the ground. In your pre flight planning you will know that your destination elevation is say 300' and so if the circuit height is 1,000' you know that you want to enter the zone at 1,300' on the QNH. As long as you hit that mark, as you proceed in the circuit you'll be flying mostly by visual clues so there's no need to change to QFE.

In your case I would just 'think' QNH

Flying from somewhere without active ATC / a/g then I hope you know the elevation of your airfield. If 450' simply twiddle the knob until your altimeter shows 450'. (Make sure you move the dial the right way and don't end up 1,000' out )You have therefore set QNH. If you pick up a nearby ATIS I doubt you'll need a 1 hpa change - and do we really fly to 30' accuracy?

Assuming your circuit height is 1,000' return to your circuit at 1450' and fly a visual circuit to land. (If you think you want to be at say 700' AGL as you turn final the only mental maths you need is that you've dropped 300' from your arrival height so that will be 1150' on your altimeter.)

[Paul_Sengupta]

2) Do I actually need to know the DIFFERENCE in altitude between where the QNH is measured and my airfield, rather than just deducing the full field elevation?
* scuttles off to find field elevation of East Mids* It is 306' AMSL.

No. QNH is the mean sea level pressure.

If you were given the QFE at East Mids, then you'd have to take the difference between the elevation there and the elevation at the other field.

[TopCat]

1) When I hear the QNH, let's say 1002 hPa, am I correct to then calculate the lower pressure due to airfield elevation, deducting 1 hPa per 30', thus at a QNH of 1002, minus 15 hPa (450' ÷ 30' ) and set 987 hPa in the window?

Yes, if said airfield elevation is 450'.

Your height above the airfield is (almost always) less than your height above the sea. So to set the QFE if you've been flying on QNH, wind the knob in whichever direction reduces your indicated height. This will also help to prevent accidentally mentally adding it on rather than subtracting it.

Draw it for yourself on a diagram, until you are sure you understand it.

You can also set an approximate QNH on departure by setting the altimeter to read the airfield elevation if the actual value isn't available. And in any case you should check that you've been given (and heard) the correct value by checking that the altimeter reads approximately the airfield elevation before you take off.

2) Do I actually need to know the DIFFERENCE in altitude between where the QNH is measured and my airfield, rather than just deducing the full field elevation?
* scuttles off to find field elevation of East Mids* It is 306' AMSL.

No. The QNH is always the sea level pressure, irrespective of where it was measured. That pressure can change over significant distances, but it's of no consequence if the QNH is recent and closeish. If East Mids is near your base, neither Tatenhill nor Leicester (439 and 469 feet elevation respectively) is anywhere near far enough away to worry about whether a recent East Mids ATIS QNH is close enough.

Take a look at isobar charts, and see for yourself how far you have to go before the pressure changes enough for you to care about circuit height accuracy.

You should aim to develop the ability to know roughly what being at the right height looks like in the circuit anyway.


However, I do very much agree with those citing airspace busts as a risk of flying on QFE. You want to set QFE not too far from the airfield (and not until the base of CAS stops getting lower as you approach the field), and once you set it, a mental note not to climb above the new indicated height will help avoid that.

[T6Harvard]

Brilliant!! Thanks all of you. It makes absolute sense. I really appreciate the time you've taken.

Obvious main point is to make sure I know which setting I am looking at if I do swap for arrival

As I said, I am very new but it was in my mind that surely the base and final legs are flown largely by eye, after a quick scan as you turn onto base.

I have sooo much to learn but what fun it will be