Primarily for general aviation discussion, but other aviation topics are also welcome.
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By Cub
FLYER Club Member  FLYER Club Member
#1483017
2Donkeys wrote:
Cub wrote: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?


Factors that should have been considered by the pilot of the M20:

1. The flight is a Training Flight and by definition is always going to be a lower priority than normal air traffic.

2. An IFR flight plan to operate within CAS was submitted and apparently rejected or lost in the system. Presumably, either an acceptance of the flight plan was received and then Southend did not have the flight plan or the flight plan was rejected. In either case the pilot had to then make a decision to operate the flight outside of CAS with knowledge of the forecast/actual weather conditions. It would appear that, whilst still on the ground, the pilot could have chased the flight plan in order to conduct the flight as originally intended.

3. At some point the 'instructor'(?) elected to give pseudo 'radar vectors' to his/her 'student' to simulate the type of service they anticipated when planning the original flight, but with no knowledge of what these 'vectors' would bring them into conflict with in IMC.

4. At some point the M20 crew will have been made aware that a radar service was not available from Southend and at that point had the opportunity to consider a range of alternative options given the anticipated/actual in-flight conditions. I am considering remaining inside Southend CAS/returning/Farnborough LARS/Thames Radar all of which could represent a significant mitigation to the risk of operating IFR in IMC outside of CAS.

5. Having fortuitously, been given radar derived traffic information under a Basic Service the pilot had the opportunity to request a different service, an update on the traffic, self-initiate a turn away.

Given all of the considerations and opportunities above I find it very surprising that none of the 'barriers' to prevent a mid-air collision appear to have been deployed.
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By 2Donkeys
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#1483021
Interesting stuff:

1. The flight is a Training Flight and by definition is always going to be a lower priority than normal air traffic.


I can see how that works in controlled airspace. That was not the environment here. It would be interesting to know how this 'lower priority' would manifest itself outside controlled airspace. Are you suggesting that a Basic Service might be given to a training flight in order to provide a Traffic Service to a non-scheduled GA flight?

It is also not clear to me that any of the controllers relevant to this specific incident would have known that this was a training flight until the report was filed.

2. An IFR flight plan to operate within CAS was submitted and apparently rejected or lost in the system. Presumably, either an acceptance of the flight plan was received and then Southend did not have the flight plan or the flight plan was rejected. In either case the pilot had to then make a decision to operate the flight outside of CAS with knowledge of the forecast/actual weather conditions. It would appear that, whilst still on the ground, the pilot could have chased the flight plan in order to conduct the flight as originally intended.


Agreed. I would have wanted to know far more about why my FPL had disappeared, particularly given the weather.

3. At some point the 'instructor'(?) elected to give pseudo 'radar vectors' to his/her 'student' to simulate the type of service they anticipated when planning the original flight, but with no knowledge of what these 'vectors' would bring them into conflict with in IMC.


You lose me there. I 'give myself vectors' every time I fly IMC outside controlled airspace. They are the headings on my PLOG/Skydemon/GPS. If instead of following my PLOG the instructor next to me gives me my headings, I am no greater or lesser risk of conflicting with another aircraft, all other factors being the same.

4. At some point the M20 crew will have been made aware that a radar service was not available from Southend and at that point had the opportunity to consider a range of alternative options given the anticipated/actual in-flight conditions. I am considering remaining inside Southend CAS/returning/Farnborough LARS/Thames Radar all of which could represent a significant mitigation to the risk of operating IFR in IMC outside of CAS.


Agreed in part. Assuming that they wished to fly at all, they had the option of considering Farnboro/Thames to provide a radar service. That free call would have exposed them to a chunk of time during which they enjoyed no service, and indeed, may well not have benefited from anything better than the original Basic Service anyway. It is far from a given that a Traffic Service is available on demand from either agency.

5. Having fortuitously, been given radar derived traffic information under a Basic Service the pilot had the opportunity to request a different service, an update on the traffic, self-initiate a turn away.


The report acknowledges that the PA31 is manoeuvring at the time that information is passed to the M20. Resolving such a conflict is not easy. I also note that from the M20 being given traffic information to the CPA is 16 seconds or less. I'm not sure how much time you think it might take to upgrade to a higher service and take an avoiding steer might be, but I guess that it is considerably more than that.
Last edited by 2Donkeys on Thu Sep 08, 2016 10:16 am, edited 1 time in total.
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By Cub
FLYER Club Member  FLYER Club Member
#1483023
2Donkeys wrote:
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.


Surely the answer lies in the SERA rule referenced in the report; "An aircraft shall not be operated in such proximity to other aircraft as to create a collision hazard." Once made aware of the proximity of the other aircraft, both pilots have an equal responsibility to discharge their obligations under the rule, regardless of their flight conditions.
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By 2Donkeys
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#1483026
I'm not questioning the wording of the rule - rather the practicability of an aircraft in IMC being treated as being able to deconflict as easily as one which is (supposed to be) in VMC. Particularly, against a manoeuvring target
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By Cub
FLYER Club Member  FLYER Club Member
#1483031
2Donkeys wrote:
1. The flight is a Training Flight and by definition is always going to be a lower priority than normal air traffic.


I can see how that works in controlled airspace. That was not the environment here. It would be interesting to know how this 'lower priority' would manifest itself outside controlled airspace. Are you suggesting that a Basic Service might be given to a training flight in order to provide a Traffic Service to a non-scheduled GA flight?

It is also not clear to me that any of the controllers relevant to this specific incident would have known that this was a training flight until the report was filed.


I am sorry, I failed to make my point clear. I was making the point as a consideration for the pilot rather than any controller, in this situation. The pilot will have planned and considered the flight on the basis of it being a training flight and should have annotated any flight plan accordingly. On that basis, training flights, in the a busy TMA environment are often subject to delay or on occasion refusal to be accommodated within controlled airspace. My point was that this will have been known to the pilot ahead of any loss/rejection of the flight plan and a safe, robust alternative must of been a consideration at an early stage in the planning.
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By Cub
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#1483042
2Donkeys wrote:The report acknowledges that the PA31 is manoeuvring at the time that information is passed to the M20. Resolving such a conflict is not easy. I also note that from the M20 being given traffic information to the CPA is 16 seconds or less. I'm not sure how much time you think it might take to upgrade to a higher service and take an avoiding steer might be, but I guess that it is considerably more than that.


At 0929:30 the Southend controller had opened the radar position and, although the M20 pilot was still under a Basic Service, provided Traffic Information about the aircraft orbiting to the south of their track. The M20 pilot had just made a left turn onto a westerly heading at this point and reported that he was IMC.


CPA occurred at 0929:46 indicating 300ft and 0.6nm, although because of the relevant positions, speeds and routing of the two aircraft, this proximity continued for several seconds until, at 0929:50, the M20 pilot reported to Southend that he had the PA31 in sight and, at 0929:53, the PA31 pilot reported to Thames Radar that he was visual with the M20 and was climbing again.


The M20 instructor presumably initiated a pseudo 'radar vector' onto a westerly heading and was then (0929:30) given the traffic information about the aircraft orbiting to the south of their track. At that point the M20 reports IMC. Surely that was the opportunity to request a Deconfliction Service and/or initiate an immediate right turn away from the reported conflict, regardless of the request for a change in service. In reality the M20 pilot elected to continue on the heading without visual acquisition, any update in the traffic information, or initiating any turn away for the next 20 seconds during which time the two aircraft continued to close for 16 seconds to a CPA indicating 300ft and 0.6nm and then fail to diverge for another 4 seconds at which point the M20 gained visual acquisition (0929:50). To me, continuing for 20 seconds in this scenario without initiating any action to resolve the confliction either demonstrates a level of ignorance of how to resolve the confliction or an arrogance that the 'big sky theory' is going to save us all.
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By 2Donkeys
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#1483045
It seems to me that the first the M20 heard was at 0929:30, and the CPA was 0929:46 as described at the top of page 4. That is is the essence of this airprox, from M20's standpoint (maybe he would have done better talking to somebody else, maybe not).

The information offered to the M20 pilot was that the threat was orbiting south of track. I am not sure that I would take any kind of material change of heading in response to such a prompt.

In reality, even had the M20 come somewhat right, the PA31's change of heading would still have given rise to a close shave.

The real issue for the M20 here is that the information provided to it was provided only 16 seconds prior to CPA and contained nothing (so far as we can see from the report) to suggest that urgent action was required.

You may know more from unreported transcripts.
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By Cub
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#1483046
2Donkeys wrote:The real issue for the M20 here is that the information provided to it was provided only 16 seconds prior to CPA and contained nothing (so far as we can see from the report) to suggest that urgent action was required.

You may know more from unreported transcripts.


The real issue is that M20 pilot made a series of debatable decisions in the planning and execution of a flight and when the outcome of those decisions resulted in a confliction with another aircraft, failed to initiate any action to prevent the real possibility of a mid-air collision.

I knew nothing about this incident until I clicked on the FLYER link yesterday directing me to the latest Airprox reports. I certainly have no access to anymore information than the same report that you are referring to however, I am beginning to wonder why you are defending the indefensible in this case?
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By 2Donkeys
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#1483047
I think we are reading the same report and reaching different conclusions. I believe that I know and like both pilots involved so have no particular axe to grind.

It worries me that you are implying that not obtaining a traffic service whilst in class G in IMC is 'indefensible'. I have, on many occasions, been forced into acting 'indefensibly' either through lack of availability of such a service or the inability to get a word in edgeways.

It would be interesting to hear the phraseology used to inform the M20 of the traffic, and to know whether 0929:30 is when the controller clicked the PTT switch and starting talking, or whether it refers to the end of his transmission. That could erode 16 seconds quite quickly.

We don't know this sort of detail, and it has a bearing on my view of the airprox.
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By James Chan
FLYER Club Member  FLYER Club Member
#1483050
According to CAP 1434:

"Once an ATS has been agreed, it is important to bear in mind that as the flight progresses and changing weather conditions are experienced, the choice of service may need to be re-considered. For example, a Basic Service or a Traffic Service might not be appropriate for flight in IMC, or where lookout is constrained by other factors, when other ATS are available. The relationship between weather expectations and the availability of the UK FIS need to be considered during pre-flight planning."

"If operating IFR in IMC and 'see and avoid' principles may be difficult or impossible to apply and assistance
from ATC is required to deconflict you from other aircraft in your vicinity, then it’s likely that a Deconfliction
Service will be appropriate. This is the only surveillance-based UK FIS where a controller will provide you
with this type of advice"
Last edited by James Chan on Thu Sep 08, 2016 12:37 pm, edited 1 time in total.
By mm_flynn
#1483051
Cub wrote: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


I know I am probably being a pedant, but this is the bit that really surprised me. G-EYES was clearly not being treated as IFR, nor was this flight by ATC. Moreover, the expert on the Airprox panel is in writing saying calibrator flights consciously operate VFR even in IMC, yet from your perspective they are always treated as IFR?.

I know you are a controller and I am not, but it does seem to me these flights live in the quantum world of being both and neither IFR and/nor VFR depending on the participants frame of reference (a bit of a quantum mechanics/relativity mixed metaphor )
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By 2Donkeys
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#1483052
Agreed

The dubious VFR/IMC status of the Calibrator is not reasonable (or contemplated in legislation).

It seems to me (and to the board) that the direct cause of the airprox was the Calibrator's turn towards the conflicting aircraft in reliance on TCAS1 data without having visually acquired the aircraft (against the TCAS1 operating procedures)
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By Tall_Guy_In_a_PA28
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#1483056
Based only on the information in the report it seems to me that if both pilots had relied entirely on 'big sky theory' rather than TAS and RADAR derived information, they would have passed each other no closer than 0.5 mile laterally and at least 200ft vertically, blissfully unaware of each other.

I am surprised that Thames RADAR have been suggested as a viable option for a deconfliction service for the M20. When Farnborough coverage was extended to the East the information promulgated to GA pilots was that Thames would no longer provide any service OCAS, except (iirc) in connection with Biggin IFR traffic.

I think the fact that the M20 was on a training flight and on simulated vectors is a red herring and not really relevant. Apart from the fact that I only fly VFR/VMC these days, I can easily see myself in the same position as the M20 pilot and honestly do not know what I would have done differently. I certainly would not expect Southend to open a RADAR position just for my benefit (as has been suggested), so I have learnt something useful from this discussion.
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By Gertie
#1483062
2Donkeys wrote:It worries me that you are implying that not obtaining a traffic service whilst in class G in IMC is 'indefensible'. I have, on many occasions, been forced into acting 'indefensibly' either through lack of availability of such a service or the inability to get a word in edgeways.

... and when you do get a service, WTF are you supposed to do in response to being told, as is not infrequent, that there's an aircraft that might possibly conflict but "no height information"? "Oh well, he's probably VMC well below us" said an instructor to me once.
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By Cub
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#1483064
Well I will dip out at this point.

I picked up on this report because rarely do you read circumstances where two individual crews had several opportunities to manage the risks associated with their respective tasks and simply failed to do so to the extend that a significant risk of collision resulted. Unfortunately, I find it even more disappointing and particularly surprising that contributors to the thread also seem to find the apportioning of blame between either crew or endorsement of either crew's actions, on the basis that, "I would have done the same", a useful and justifiable exercise when so many barriers preventing a possible mid-air collision and unnecessary loss of life where ignored.

I don't know the individuals involved but would quite happily say exactly the same things to them in person in an attempt to hopefully reinforce the obvious learning points from this particularly worrying event.