TAC
After years of weapons trials analysis, it is my opinion that the Boeing effort is not bad based upon the available data (which is all it is); it makes sense to me and, in the absence of anything similar in the public domain done by anyone else, it is a good starting point and framework for anyone else interested in doing a better job. Why do you say it is “not very good guesswork at that”? Is there a better analysis available that I can access?
Arkroyal
I almost forgot – you wrote:
<<… The visual references for VFR flight would still have to be met …>>
Not for a helicopter in SVFR – I think you’ll find that provided they were in clear contact with the ground (the sea, in this case) they could proceed SVFR at low level with as little as ˝ a mile lateral visibility – this concession because helicopters can always SLOW DOWN.
This gives helo pilots a great deal of discretion: if they are happy, their actual speed is up to them; in this case they would have known that the mist started at the shoreline and their waypoint was more than ˝ a mile before it; provided that they intended to turn ˝ a mile before the mist, they were not doing anything wrong under SVFR; they would not have let the SuperTANS influence their judgment of their distance off the coast (this crew in particular had misgivings about its accuracy as has been discussed at length here before); if they were keeping their eyes on the range to a DME beacon (normally very accurate) its clear, numeric readout could strongly influence their visual judgment of their distance off a grey, amorphous mass; they could see the (mist covered) landmass ahead but could have become disorientated range wise – they could have just turned away or slowed down but what does a pilot do when first disorientated? – looks at his instruments? – and if a readout says he still has ˝ a mile to go, could he then have been reassured to carry on?
The point is, if the DME readout was wrong (for whatever reason) and could therefore have misled the pilots, they could not have been held negligent as they were intending to turn away from the mist at a range within SVFR guidelines.
The “Campaign” group, as an interested party, could put together a set of formal questions which could settle this once and for all – I suggest the following for starters:
Was SVFR agreed with ATC;
If so, what squawk code was assigned and what was there any special significance;
(this could explain 7760)
Was there a DME transponder at the time on the Mull that a low level helicopter on this approach could use;
What of the radar recordings that apparently existed shortly after the crash;
(the radar track could help establish that the a/c was under control or at least not deviating madly from its intended course or help with the analysis of its actions)
What explanation is there for the unanswered radio call (or lack of recording after this point) – was there definitely no other transmission heard – was not further radio dialogue expected with an a/c at low level intending to cross the approach to a main runway (Macrihanish);
Was there a special practice for this leg towards the Mull (eg by 7 Sqn);
What equipment were the US SEALS recovering – were ANY of them interviewed (if not why not).