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National CAA policies around Europe on busting pilots who bust controlled airspace (and danger areas)

Does anybody here ever request transponder checks with ATC? This thread has made me a lot more paranoid about skimming below airspace, given the apparent potential to have an in-spec transponder, fly outside of controlled airspace, and still be infringing.

EGCW

kwlf wrote:

Does anybody here ever request transponder checks with ATC

You can do that in ground by looking at the transmitted ALT on mode C screen,
As long as FLxx<ELV, it will not send anything weird on mode C (save you few QNH calcs)

Even when ATC call you for alt verification, I have no clue what calculations/tolerances they apply on the background, so one has to keep some trust and good faith in the system to avoid getting paranoid, there are other important tasks while flying that debugging transponder outputs

ESSEX, United Kingdom

Was there anyone (or do you know of) that was busted for a false positive (transponder reported higher than real)?

I always log my flights (SD, but FF also does it and I imagine so do the others I haven’t tried). I’d imagine in the case of such positive they might be very helpful and stop further action.

Yes; mentioned here.

It appears here

3 of them in June:

The above URL now shows some data for June also. That site is being continually edited, so here is a local copy:

Facts_stats_and_incidents_Airspace_Safety_pdf

Some interesting points in there. The main one is that infringers who did the Gasco previously get their license suspended

You don’t get much more hard-hitting than that.

Bear in mind that roughly 20 pilots get sent to Gasco each month. These 20 need to totally avoid all risk of touching CAS/ATZ/etc for two years afterwards.

To me, this means no more VFR flight in the UK, other than along the south coast, or way out over the sea.

You can do that in ground by looking at the transmitted ALT on mode C screen,

That’s true, and the pressure altitude value shown there should be transmitted to ATC, but what we don’t know is what altitude is being shown to the ATCO on his screen. It will be the pressure altitude corrected by the radar server using the local QNH. I bet you anything that flying 100ft below CAS is no longer a good idea, because the resolution in the return is 100ft so 2400 could become 2500 and when corrected it could be even (very slightly, perhaps 30ft, because that will be the QNH resolution) higher.

It would be an interesting exercise…

I wonder where say Farnborough’s QNH is taken from? It’s a large area.

Administrator
Shoreham EGKA, United Kingdom

It gets better.

This outfit is apparently processing some pilots whose licenses were suspended. They charge £99, plus your travel and flying costs/time.

Administrator
Shoreham EGKA, United Kingdom

I meant did anyone have to attend the course due to the transponder reporting a bust when there wasn’t (false positive). If I read you right, it looks like no one has. Having the GPS logs seems like a reasonable défense against legitimate false positives.

I don’t think it’s at all clear that “obtain information” implies or requires two-way communication. The RotA prescribes exactly what is required and we don’t need to gold-plate it.

If we monitor a Radio or Info channel for 5-10 minutes we know all that the operator can tell us, and certainly all that we need to know so as to transit an ATZ safely at, say, 1,900 ft agl. Then we call to say that’s what we’re about to do. We are in command. If the geezer on the ground offers further information, we can decide what, if anything, to do about it.
Glenswinton, SW Scotland, United Kingdom

Peter – I cant see any infringement figures for June, where are you referring?

I meant did anyone have to attend the course due to the transponder reporting a bust when there wasn’t (false positive). If I read you right, it looks like no one has.

My reading of the data is in agreement with you, but most likely because nobody would get that far. Anybody who got the initial NATS letter telling them of the bust, then the CAA letter, etc, and who is sure they didn’t bust and think they have supporting evidence is going to kick up a massive stink, threatening to go to a court if necessary. Then the CAA will ask for an engineer’s report on a transponder test.

Perhaps someone not familiar with the current process discussed here might prefer to cut their losses with the Gasco hotel session, which is sure to be cheaper than a court case especially given the CAA’s long established tactic of going for much higher costs for a NG plea. Personally I would not do that; this is not a £60 speeding ticket on which the cat gets 3 more lives. This is a step towards license suspension (pending some undefined process and taking an unknown time) and that is a much more serious curtailment of one’s liberty. But I appreciate many pilots are only just hanging in there financially.

Having the GPS logs seems like a reasonable défense against legitimate false positives.

Maybe it is, but the GPS altitude is not the baro altitude on which all this stuff runs.

I cant see any infringement figures for June, where are you referring?

You are correct; none are published fo June. The numbers on that site are the numbers of decisions during each month. These lag the offences by 1-2 months.

So one cannot take e.g. the busts for May

and relate them to the decisions taken in May

One cannot relate them to decisions taken in any later month either.

They are basically unrelated and there is no way to relate them. The data is being released in a way which makes it impossible to do that.

Administrator
Shoreham EGKA, United Kingdom

Ibra wrote:

Even when ATC call you for alt verification, I have no clue what calculations/tolerances they apply on the background,

Just 27ft per hPa difference between the QNH use by the ATSU and 1013.25hPa. Tolerance is 200ft. But as already discussed the tolerance applies only if you are speaking to the ATSU which “owns” the airspace.

Noe wrote:

I always log my flights (SD, but FF also does it and I imagine so do the others I haven’t tried). I’d imagine in the case of such positive they might be very helpful and stop further action.

As mentioned the GPS altitude is not the same as the baro altitude, so won’t set you free if you just infringe by 100ft. If the altitude encoder has gone really bad and is wrong by thousands of feet it would be worth a try.

Nympsfield, United Kingdom
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