Originally Posted by Sedbergh
The Cessna is said to have had a transponder, but it was switched off. The collision occurred at 650 feet AGL in open airspace. IF the Cessna had been fitted with Mode S, would an FIS controller have been able to see it (by radar) at that level?
Probably not, because as the report states:
"Analysis of the recordings of local military and civil radars failed to show traces of the tracks of either aircraft. It is considered that this was because both aircraft were below the base of primary radar cover and neither aircraft appeared to be using its secondary radar transponder." (SSR has a base level too and they'd have to have been above that)
Originally Posted by Sedbergh
Would an FIS controller have had time to warn the Cessna pilot of an impending collision?
Probably not because (a) on a FIS the controller could only have guessed which radar contact (if he could see one) was the Cessna, (b) both the Cessna and the Tornado would have been unverified, (c) traffic on a FIS unlikely to be given traffic info except in very general terms, and (d) in circumstances where a light aircraft and fast jet are on a collision course, giving traffic info to the light aircraft is highly unlikely to resolve the conflict since the conflicting FJ could be anywhere in the light a/c's 360 degrees and the light a/c can't move quick enough to get out of the way. Give tfc info to the FJ and you have a chance of resolving - except when the pilot's heads-down changing frequency as I believe he was thought to be in this case.
Originally Posted by Sedbergh
Would the FIS controller have been able to see and contact the Tornado?
Only if the Tornado pilot was in contact with that particular controller. Otherwise it would have required a phone call to the controller whose squawk the Tornado was wearing or, more likely, a feeling of helplessness at an observed squawk of 7001 which indicated that the Tornado was in the low flying system and therefore almost certainly talking to no-one.
Well done for spotting a debatable case in the CAA's RIA. Is someone doing a thorough analysis of all the quoted cases to see how many others there are?
Another factor in this case is that it implies that in future Mode S will allow LARS controllers to provide a RIS to everyone previously getting a FIS - or that TCAS will sort everyone out. On the first, what do all you LARS controllers think about the workload implications? On the second, NB this is not an argument for Mode S, it's an argument for current ACAS and Mode C.
NS