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National CAA policies around Europe on busting pilots who bust controlled airspace

Peter wrote:

And the vast majority of these apps have no aircraft intercom connection (it’s not trivial to do).

It’s incredibly trivial to do in an awful lot of planes. Even my radio has an aux in (I now clip an Android phone to the top of the panel, so it’s visible just below the windscreen – and it has a simple audio lead that goes to the aux in). Many people have Bluetooth headsets, too.

But on vertical navigation – it’s hardly a surprise that pilots make such a hash of it – it’s done badly in the UK. Let’s contrast the USA and UK lower airspace:

1. USA: You use the appropriate altimeter setting (QNH) for the airspace you’re in. End of story.

2. UK: You could be on regional QNH, the actual QNH, the QFE from some airfield, you could be set to 1013 (and the transition altitude changes depending on air pressure and where you are). Regional QNH is often many millibars lower than the actual QNH, and can put you a good 200 feet higher than you think you are – and if you’re near very low airspace shelves, then you just busted even if you follow “TAKE 2” (especially if for instance your altimeter reads 50 feet too low and your transponder 50 feet too high!). Forget to switch from QFE to QNH, and you can be a couple of hundred feet higher than you think you are. This is compounded by Ofcom’s money grab for ground aviation radio licencing, which means many airports have turned the transmit power of their ATIS right down, so casually getting the QNH for some airfields can be a problem, unless you’re already talking to London or Scottish info.

Get rid of all this bollocks. Train pilots to use the QNH for the nearest controlled airspace, always. Make it clear whose QNH you should be using on charts (in some places this is done).

I bet a significant number of vertical busts are because people were not using the QNH of the airspace they busted. Things like still being on 1013, the transition altitude has changed, and not noticing that the next block of airspace says [D] 4500’ rather than FL45, and being 500 feet higher than you think you are. Things like being on the Barnsley Regional as you get close to Manchester.

3. Other compounding factors. IIRC, the UK requires 1000’ between an airspace floor and the traffic inside, the USA requires 500’. The USA gives good evidence that this is perfectly safe, and if we adopted US standards, things like the Manchester LLR would now have a ceiling of 1800’ meaning most people don’t have to get anywhere near it. It’s a lot easier to “TAKE 2” when it means flying over Warrington at 1500’ AGL instead of 1000’.

Last Edited by alioth at 11 Jul 19:08
Andreas IOM

alioth wrote:

It’s incredibly trivial to do in an awful lot of planes. Even my radio has an aux in (I now clip an Android phone to the top of the panel, so it’s visible just below the windscreen – and it has a simple audio lead that goes to the aux in).

Well… If there is an aux in socket then very likely it is muted whenever there is a transmisson on the COM frequency. That makes it somewhat less useful for alerting. If you wire an unmuted input of the audio panel to a socket, you’ll have problems with power and/or impedance levels. I’ve tried it and the phone/tablet is barely audible. I’ve bought a transformer to get better impedance matching and see if that helps. If not, you’ll need an amplifier.

Last Edited by Airborne_Again at 12 Jul 08:56
ESKC (Uppsala/Sundbro), Sweden

Perhaps there’s a small market for making mixers that can be put inline with the phone out socket and the headset (I have a mixer IC in my junk box that’ll do the job just fine, getting the input impedance right in the case of using a mixer IC/amplifier is just a matter of a resistor network). There are also bluetooth audio modules around, add one of them and you can do it without the aux lead and add bluetooth to headsets that don’t have it.

Last Edited by alioth at 12 Jul 08:43
Andreas IOM

If the UK CAA had any nous at all they would have asked all UK maintenance and avionics companies to report monthly the numbers of Mode S transponders that they were installing and how many were new installations vs Mode A/C replacements.

Then we’d actually have some data rather than having to just guess.

But it stands to reason that increased Mode S must make a big difference. Have we any record of anyone at all being sent on a GASCO course that was squawking Mode C or A (and not talking to anyone) or not squawking at all – i.e. non-trivial to track down and prove a case against?


Re. vertical busts:

There are typically few safety cases for following one horizontal profile v. another so we are likely to choose to remain well clear of airspace horizontally and GPS makes this relatively easy.

However, when the ceiling of controlled airspace is low, maintaining good margins from it conflicts with the aim to remain as high as possible to increase safety so there is sometimes a good reason to want to skim the base of airspace. Diversions to avoid vertical airspace are generally likely to be much larger than diversions to avoid horizontal airspace, because there is much more airspace with a floor than there is airspace that reaches the ground.

GPS altitude doesn’t always correlate closely with pressure altitude, so devices such as the Airspace Aware are not 100% capable of stopping vertical busts, and they are likely to be much more effective at preventing horizontal busts.

Are there any GPS maps that take a pressure altitude input, perhaps from the transponder encoder?


kwlf wrote:

Are there any GPS maps that take a pressure altitude input

Doesn’t SD do this? but from the altitude in the phone/tablet (if any).

That’s my point: most phones will only be able to get height above sea level from GPS; I’m sure there will be a few with barometers/altimeters but as far as I’m aware it’s not a common thing for a phone or tablet to include.


LeSving wrote:

Doesn’t SD do this? but from the altitude in the phone/tablet (if any).

Even if it does, the pressure difference between the cabin and the outside air is large enough that it is unlikely that such pressure altitude is more accurate than GPS altitude.

ESKC (Uppsala/Sundbro), Sweden

Indeed; GPS altitude does not work unless you allow a generous margin of several hundred feet.

The cockpit pressure is also a bit off – 50ft to 100ft. In the TB20 using the alternate static increases the altimeter reading by about 100ft. So using the cockpit pressure would make you fly 100ft lower, which is “safer”. OTOH I am sure this is speed and door seal (etc) effectiveness dependent.

However all these apps have an issue (for airspace warning purposes) in that they cannot know if you are flying an altitude or a flight level. You have to set it up correctly for the present moment.

The problem is that you will be processed as an infringer if the pressure altitude from your transponder (corrected, if applicable, with the local QNH of the radar server) is seen inside CAS – even by 100ft or possibly less. They don’t allow any margin for altimeter errors, so you have to do that yourself and fly say 300ft below the base of CAS if you don’t know the accuracy of your altitude encoder but believe it to be within 200ft.

There are barometric “consumer devices” (e.g. Tissot watches) but they are really inaccurate. And you have to manually set the QNH in them.

Shoreham EGKA, United Kingdom

Oh come on. Most aircraft have an altimeter, that altimeter is subject to recalibration and checking on a regular basis, in the PPL we are taught how to use it. ATS give us a QNH to put in the window, and generally that doesn’t change much over a short timescale of a GA flight. Even if you don’t change your QNH going from one region to another you’ll most likely only be 30 feet out. OK you have to know whether you are operating on altitude, height or level, but surely everyone is operating the same system. If people are being fined, sent on courses or otherwise penalised for operating within that framework including the margins for error as set out in ICAO and EASA guidelines then that is just stupid and the people doing the penalising need to be held to account. After all CTA’s are supposed to be designed to take into account these margins for error.
Referring to the title of this thread there is an REX published here this week regarding a French pilot who took off from a Spanish airport and got confused by the chart using 1000 ft/sfc when he was using 1000ft QNH. It caused him to believe that if he followed the departure procedure to the North of a Pzone that he would be too low and would hit the mountains so he took the decision to avoid the Pzone by the south. This led him to both enter class A airspace and to cut across the final approach course of a much larger airport.
He reports that he later discussed what had happened with the tower controller and as I understand it his sanction was to write the REX report when he returned to his home airfield in France along with what he had learnt and how he was going to avoid making a similar mistake in the future.(dgac safety advisors will also add their comments and advice). If I am correct in my understanding of these sanctions I would say that the Spanish ATC has been eminently sensible as IMHO the pilot concerned and all French pilots will learn more and are hopefully less likely to make similar mistakes in the future than they would do by being forced to attend a course. I am not saying that such courses do not have a place, IMO they can be very valuable if you attend because you want to.

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