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Can you get busted for this? (two P areas meeting at a point)

Of course the altitude at which an airspace starts belongs to THAT airspace! At least that’s my understanding of the matter …

Well, it’s not that one side has an airspace and the other side doesn’t have any – so this is why your interpretation is unworkable. There’s always an airspace on both sides, even if “only” G. Therefore the rule that the dividing level belongs to the less restrictive airspace.

LSZK, Switzerland

In the US, if you are close enough for the radar track to be inside the airspace as determined by the FAA, you can get violated. We are cautioned not to use GPS or DME within a mile of the airspace to maintain separation and avoid a bust.

KUZA, United States

if you are close enough for the radar track to be inside the airspace

That is a good point. Radar is not all that accurate – maybe 1nm at 30nm (laterally). GPS is normally far more accurate. But if ATC says you busted then presumably you “have” busted and that’s the end of it.

Administrator
Shoreham EGKA, United Kingdom

Radar is not all that accurate – maybe 1nm at 30nm (laterally).

I wouldn’t be so sure of that. After all, they use radar to shoot down aircraft that move at the speed of sound 45,000ft above. The only time I was fined for an airspace bust, the evidence was a pile of military radar plots that showed me about 1NM inside the TRA for less than two minutes. 1000 Euros was the bill.

Last Edited by what_next at 19 Jan 14:42
EDDS - Stuttgart

That’s different; radar guided missiles work by a ground radar tracking and illuminating the target, and the missile homes in on the reflected radiation. So it will “always” try to reach the target exactly.

ATC (PPI) radar is not that accurate.

But I agree with you that a radar plot is not likely to be possible to argue with.

I still think it was a good theoretical question

Administrator
Shoreham EGKA, United Kingdom

But I agree with you that a radar plot is not likely to be possible to argue with.

The advice apparently given by a DFS guy is in this case to ask for the radar plot of all the radar heads tracking you. Chances are that they disagree by a mile or so.

And yes, military radar is quite a bit more accurate than civilian radar, so you could be unlucky in that they might have military radar plots – but that seems to be far from always.

LSZK, Switzerland

During commissioning and subsequent routine flight inspections, the horizontal accuracy of an airfield radar is to be =<300m with a recommended resolution of =<210m. The maximum acceptable error in azimuth is to be 0.15deg whilst still remaining within the 300m criteria.

Back to the scenario, I saw something similar some years back where an RAF Jaguar decided to fly VFR across the top of a CTR/CTA which was coincident with the bottom of an airway. He argued that the demarcation line wasn’t in either Class D or Class A; he got busted. :)

Last Edited by Dave_Phillips at 19 Jan 15:40
Fly safely
Various UK. Operate throughout Europe and Middle East, United Kingdom

the horizontal accuracy of an airfield radar is to be =<300m with a recommended resolution of =<210m

At what range?

That is the key. The azimuth error is obviously proportional to the distance from the radar head. I vaguely recall from a UK ATCO that their radar is accurate to about 1nm at 30nm. I think it may have been Birmingham.

Administrator
Shoreham EGKA, United Kingdom

The azimuth error is obviously proportional to the distance from the radar head.

It is. But the range error/accuracy is not dependent on range (same as DME!). So if your don’t-cross-this-line line is at more or less right angles to the wave propagation, they can “see” very accurately how far on the wrong side you have been.

Last Edited by what_next at 19 Jan 16:13
EDDS - Stuttgart

But the range error/accuracy is not dependent on range (same as DME!)

But DME accuracy clearly is dependent on range, namely +-0.25NM+1.25% (of the range) (says Pans Ops / ICAO Doc 8168)

LSZK, Switzerland
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