[James Chan]

The discussion around infringements got me thinking:

What happens to pilots when, after been cleared into CAS IFR or VFR, drift from their assigned altitude (i.e. level bust) or lateral limits?

I’d imagine something similar to CAIT changes their colour on a controllers screen such that they may be nudged back to their assigned altitude / space.

How many of these happen every year in UK airspace? Are some pilots asked to attend a level bust course?

What about runway incursions?

I guess I ask because these incidents, similar to infringements, can cause anything ranging from changes in workload of those around them to risk of collision, although unlike infringements, they have the benefit of being on frequency.

[lobstaboy]

The atcos can answer this properly of course, but I'd imagine that because they are on frequency they don't count as "unknown traffic" so sorting it out is simply a radio call to the one who's made the mistake not huge amounts of rerouting or stopping departures and so on.
I've offended in this way and got a quick call - all sorted in about two minutes, no-one said anything else...

[JonathanB]

A level bust is a reportable event so an MOR should be filed.

[PaulB]

A level bust is a reportable event so an MOR should be filed.

I bet the pilot(s) don’t get sent on an awareness course!

[BoeingBoy]

Tolerance in Class A airspace is generally +/- 200' before concerns are raised.

It depends on the equipment you're flying as to whether you get any warning. Most airliners have at least an aural warning and on the flat screen displays a flashing altitude display after 300' has been breached.

ATC will ask what's happening after 200' as they will get a deviation alert before we do.

The main difference is that nearly all aircraft in Class A airspace will be using an autopilot with at least altitude hold, if not full vertical control. It's a brave man who in this day and age ventures long distances IFR in manual flight. That said, there's no reason why you can't.

You're right though. No tea and biscuits unless you've been negligent. Matters are normally cleared up there and then.

[AlanM]

Most level busts we get for light aircraft are on departure. (Irrespective of whether not above 1000ft or not above 2000ft are issued)

As James said, they are more often than not on frequency so often of little consequence. Also, more often than not GA aircraft are VFR so even with an IFR descending on top I would just give Traffic Info.

If IFR or SVFR and standard separation is lost then that is different, with an MOR instantly filed.

As for runway incursions and driving past lit stopbars - again an immediate MOR. The DCA has already written to one operator at Jersey for driving over a stopbar.

Remember that CAIT is a NATS tool (possibly only on the NODE-L Radar displays?). Not everyone has that but we do have an AIW - an Airspace Infringement Warning that flashes red and alerts us.

To sum; infringements are unknown and therefore cause a whole load of wider issues. Generally, there are safety nets (both on our radar display and in the cockpit such as TCAS) to mitigate other errors and allow defensive controlling techniques.

[CloudHound]

What extra info would turn an unknown infringer into a known entity?

[GonzoEGLL]

What extra info would turn an unknown infringer into a known entity?

What they are going to do.

[rdfb]

Most level busts we get for light aircraft are on departure. (Irrespective of whether not above 1000ft or not above 2000ft are issued)

Does that mean that for "not above 2000ft", I can aim to fly at 2000ft and if I can maintain that with less than a 50-100ft deviation upwards, I'm OK?

I have previously maintained 1400ft on a "not above 1500ft" deviation for margin, but been worried about the glide clear rule. It would certainly be better if I could actually maintain the actual highest level cleared rather than needing extra margin if a margin is already being applied by ATC.

[AlanM]

@rdfb

If I am cleared to fly not above a level I will fly up to that point. So not above 2000ft Is SFC-2000ft.

As and ATCO I will verify your level. If it is within tolerances (ie you say 2000ft and you are showing 2200ft) we are all happy and cool.

[CloudHound]

I already emit ADS-B through a Mode S txpndr and PAW. Is it SIL that’s the problem?

[skydriller]

What extra info would turn an unknown infringer into a known entity?

What they are going to do.

And right there, ladies and gentlemen, is the answer.

I said it on the other locked thread, the main reason that you dont hear about infringements as a major problem outside the UK is because in other places you would already be talking to the FIS controlling the airspace near you.

You are KNOWN traffic already and the controller knows your intentions.

The UK system is set up to create the problem!! You even get "The UK system response" when you are calling for a transit on an international flight plan. The first words spoken on call up are "remain clear of controlled airspace", I dont think I have ever heard this outside of the UK.

Regards, SD..

[GonzoEGLL]

So you’d support mandatory TMZ/RMZ around all CAS?

[johnm]

So you’d support mandatory TMZ/RMZ around all CAS?

I wouldn't but I'd support widespread Class E with a joined up ATC system. Most of the problems in the UK stem from carp airspace design and fragmented and incoherent ATC.

[GonzoEGLL]

Admirable aims, but that isn’t realistic.

What can be done with what we have to hand now?