[Cub]

I found this Airprox Report interesting reading.

I guess you can become IMC during any flight but can you actually plan to undertake a VFR flight in IMC? Surely SERA criteria stop you doing this or am I out of touch?

The whole incident raises lots of questions for me about multiple agencies serving the same airspace under multiple FISs.

[Dave Phillips]

If you are IMC in Class G you must comply with the IFR.

[joe-fbs]

Surely the rule is as it always was, "to be VFR you must be VMC"?

Off the top of my head, in that area one could comply with the IFR to be 1000 feet above obstacles but not, without entering class A, the semi-circular rule (or it may still have been quadrantal then)?

[James Chan]

The whole incident raises lots of questions for me about multiple agencies serving the same airspace under multiple FISs.

Indeed. Something I raised concerns about around a decade ago (irrespective of meteorological conditions) but received no response.

[mm_flynn]

The biggest surprise for me is that the Airprox board were 'surprised' that aircraft operate IFR in IMC in Class G with whatever service they can get from one of a diverse number of potential service providers. When I first moved to the UK (1991), I was astonished this was normal. But 25 years of experience later, I am equally astonished that any local would be surprised.

The second surprise was that a calibration flight's ops manual would let them operate VFR in IMC, as my understanding is that is explicitly forbidden. In particular, the comments in the the report that '...Calibration flights are performed under VFR...', '...whilst the actual calibration profile run is being conducted the pilot may be intermittently IMC due to the constraints of the profile run ...', aggravated by the fact that the ILS is in Class D airspace, would suggest an official casual disregard for the rules, which I do find surprising.

Separately, of course if the calibrator had been IFR at that location, nothing would have been any different as both aircraft appear to have been fully compliant with the IFR's.

[alexbrett2]

Off the top of my head, in that area one could comply with the IFR to be 1000 feet above obstacles but not, without entering class A, the semi-circular rule (or it may still have been quadrantal then)?

For the aircraft holding then it clearly wasn't in cruise flight so surely the semi circular rule wouldn't apply?

[Ben K]

At the risk of slight thread drift....anyone else think the latest batch of airproxes (that the incident the OP refers to) involved more than usual amounts of drone-based reports?

[mm_flynn]

Off the top of my head, in that area one could comply with the IFR to be 1000 feet above obstacles but not, without entering class A, the semi-circular rule (or it may still have been quadrantal then)?

For the aircraft holding then it clearly wasn't in cruise flight so surely the semi circular rule wouldn't apply?

Nor does in apply below 3000 feet AMSL

[Cub]

The second surprise was that a calibration flight's ops manual would let them operate VFR in IMC, as my understanding is that is explicitly forbidden. In particular, the comments in the the report that '...Calibration flights are performed under VFR...', '...whilst the actual calibration profile run is being conducted the pilot may be intermittently IMC due to the constraints of the profile run ...', aggravated by the fact that the ILS is in Class D airspace, would suggest an official casual disregard for the rules, which I do find surprising.

Separately, of course if the calibrator had been IFR at that location, nothing would have been any different as both aircraft appear to have been fully compliant with the IFR's.

Although a flight inspection aircraft will normally need to operate in VMC, it is to be treated by air traffic at all times as an IFR flight. it therefore has to be separated from other IFR/SVFR aircraft inside Class D airspace and I therefore find it surprising that the calibration aircraft did not at least request a Deconfliction Service when outside CAS and experiencing IMC.

[NorthSouth]

For both aircraft, the pilots were in that awkward situation - wanting to be VFR but finding themselves in IMC, and wanting to have freedom to choose their own route so reluctant to ask for a Deconfliction Service. But it's often very difficult to work out what your best course of action is when you're on a Traffic Service (PA31) or radar-assisted Basic Service (! - Mooney) and told about traffic which you need to avoid but you can't see it. Especially when you're manoeuvring. But given the need to give the calibrator protection, you would think the controller would have kept him inside CAS while orbiting

[Cub]

But given the need to give the calibrator protection, you would think the controller would have kept him inside CAS while orbiting

The controller will have given the calibrator whatever he/she asked for. This is surely all about captaincy. Rarely have I read a report where two pilots both selected multiple inappropriate courses of action that could have easily resulted in the poor old controllers having to explain to the Coroner the outcome of a completely preventable situation.

[mm_flynn]

Although a flight inspection aircraft will normally need to operate in VMC, it is to be treated by air traffic at all times as an IFR flight. it therefore has to be separated from other IFR/SVFR aircraft inside Class D airspace and I therefore find it surprising that the calibration aircraft did not at least request a Deconfliction Service when outside CAS and experiencing IMC.

I would have thought so, but why would one develop a system where you operate 'VFR'*, but are treated as IFR? A simple person like me would have thought a flight should be treated as whatever it is. Otherwise, why bother with these concepts. I am still surprised that an official member of the aviation establishment would say 'we always operate these flights VFR but fly in the clouds as required to accomplish the mission - even in class D'. It seems to validate that in the UK it is perfectly acceptable to take a VFR clearance through a Class D zone and fly inside the clouds. (Something I recognise is done, but still believe is fundamentally wrong).

IIRC one of the issues that came out on the G-EYES accident is that none of the players were particularly clear about the calibrator being VFR or IFR; and therefore who, if anyone, was doing any separation. In this most recent case it seems pretty clear both pilots where operating in the UK standard 'IFR OCAS with whatever service they were offered' and the inevitable risk that not everyone in the same area is talking with the same agency. This seems like 'life in the UK', which is why I am so surprised at the general tone the Airprox board has taken in writing their conclusion.


* This comment is based both on the classification of flight given in the report and the comments quoted by one of the members of the board

[mm_flynn]

The controller will have given the calibrator whatever he/she asked for. This is surely all about captaincy.

While that may be true of a special flight like the calibrator, I fairly frequently don't get what I ask for and have to make due with what is offered. I understand this is about the amount of resource available so don't complain. Additionally, given the separation needed on a deconfliction service, It is difficult to see that working for either of the flights in those locations or either of the controllers. On the day, I would have asked Southend for a Traffic Service, but if they said basic only, I would not have changed my plan.

[Cub]

The calibrator is treated as IFR by ATC in recognition of the fact that the crew may not always be capable of achieving see and avoid given the precise nature of their profile and associated workload. Given that ATC procedures recognise this limitation I am surprised that the calibrator would select to declare him/herself VFR when clearly experiencing IMC conditions and then select to orbit outside CAS in IMC under a traffic service. I would imagine that it is these facts that surprise the Airprox Board members.
The whole situation is then compounded by another flight being conducted in IMC, making another series of very surprising decisions given the nature of the flight and circumstances.
I am also surprised and worried by the suggestion in this thread that some of those decisions would be shared and endorsed by other people simply because they believe that that is the status quo in the south east of England. An incredibly cavalier attitude to personal and systemic risk management IMHO.

[2Donkeys]

The whole situation is then compounded by another flight being conducted in IMC, making another series of very surprising decisions given the nature of the flight and circumstances.

Could you elaborate on this? My reading of the report is that the M20 pilot is only really criticised for taking a Basic Service instead of a Traffic Service (or better) whilst flying along in IMC under IFR.

Frequently, a Basic service is all that is on offer across extensive chunks of the SE UK, either due to controller workload or the other litany of reasons with which most are familiar. To the extent that we can't turn the weather on and off, we will often fly with a Basic Service when we might prefer better, for lack of a choice. There was no radar position open at Southend when the M20 called for service, so this was his situation too.

There are a few odd statements in the report. This one jars for me.

The PA31 and M20 pilots shared an equal responsibility for collision avoidance and not to operate in such proximity to other aircraft as to create a collision hazard

In a case where one aircraft is operating under IFR in IMC whilst the other 'claims' to be VFR and therefore *must* be in VMC to honour its part of the deal, the presumption that both parties have an equal responsibility is flawed. One *should* be able to see and avoid, and the other clearly cannot.