ShyTorque
Thank you for focussing on pertinent points.
<<... if the use of this equipment was the "real" mission, why would the captain ask for a Mk1 Chinook for the flight, which definitely did not have the equipment fitted?>>
An excellent point brings us back to who above Flt Lt Tapper set up the flight changing from 2 helos to the one Chinook in the first place (I raised this planning aspect some time ago but no-one is prepared to discuss this on this thread) that person's version of the briefing would be of great value - perhaps he (JT) had misgivings about the demo and was looking for an honourable cop-out?
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<<Especially bearing in mind the small number of hours the crew had on the Mk2, and their concerns over the safety of the type, a homing demonstration in marginal weather would surely not be on the agenda; the crew would be only interested in conventional navigation to the destination.>>
Then why did they not stick to the safe route pre-planned by Lt K? (Ald-wptH-wptB.)
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<<Bearing in mind the nav kit on board, a lat. & long. passed over the radio is far more useful, btw.>>
Flt Lt Tapper would not have trusted the STANS as close in as the position of waypoint change, at their speed, with those conditions on the ground ahead. They had waypoint A already which is (rounded to convenient-to-memorise lat & long) a few tens of yards from the LZ yet which they replaced with wpt B well short of it. As I have described previously, combined with 028 on the navigator's (JT) HoSI, this suggests that they intended heading for the safe, clear track after their activity at the Mull rather than the nonsensical assertion that they would have just turned to B at that point (check out that route). For the several parameters I have given on previous occassions, it seemed that they thought they were lined up with and intended to land or close pass that LZ they would not have attempted this without some local point reference that they trusted even in clear conditions, that landscape is bereft of familiar objects making any fast approach there hairy by visual judgement alone (remember that warning for ops in South Georgia something about in clear vis distances can be very hard to judge same thing of no familiar objects). After a sea crossing, the STANS could be expected to be out by half a mile or more Flt Lt Tapper had warned others in his flight of this concern. Because of this a lat. & long. passed over the radio would not have been of any use add to this the possibility of error in the position given, poss error in the understanding of the TX, and the poss error in typing it in while on the move and you can see it's a no-brainer as I have said all along, the one thing helo pilots tend to trust above all other references is a DME system of some sort located locally, a good example being a TACAN on a heli-deck, and of course the CPLS working off a PRC112 gave the HC2s a local all weather capability of sorts. But don't get hung up on this specific equipment it is still only my guess as a candidate equipment and I did ask for other ideas what matters is that the various parameters that we have strongly suggest an excursion to the Mull as part of an extra as yet undisclosed activity getting that agreed upon is a tack to getting them cleared beyond that, it may lead to a fuller inquiry leading to real justice.
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<<I can think of no reason why these passengers would be interested in a homing demonstration in the first place. From the passenger seats they would have no way of observing and assessing the technique of any type of homing, or even seeing out of the front of the aircraft.>>
I rather think that several of them could have been sold a demo of the capability of getting in quick for an extraction in adverse conditions whether they looked out of their windows or not, they could have been informed of the conditions and how things were progressing perhaps as they swung around the lighthouse at speed they could have been told to look out, that they had got directly there, etc anyway, it wasn't going to upset their schedule and the RAF was short of flying hours for pure training so like it or lump it just so long as they accepted all the security eggs (them) being stuffed into one basket (the Mk2) and being flown towards the isolated Mull - whoever put this flight together must have had the same concerns that you raised here, ShyTorque, but with enough chutzpah it worked out.