Walter,
Your posts are becoming increasingly difficult to decipher, because of a lack of paragraphs and those strange parentheses you use. It would be useful if you could use the quote facility, or at least separate your quotes by using a new paragraph, or double space them. Thankyou.
I cannot use my "RAF contacts" to find answers to fit in with your theories, which is what you crave; again, I have told you why, before now. You can read back and remind yourself. The reasons are nothing sinister or filled with smoke, as you strangely put it, merely practical.
7000 is the transponder code for normal VFR ops, 7700 is the emergency squawk. With 7760 showing, the third digit / row needed to have the "0" selected to send the emergency code. It is entirely possible that the crewman, or the co-pilot had hurriedly only partly selected this code to indicate an onboard emergency before being tragically interrupted by the impact.
At low level any transponder code may or may not be picked up by a radar, but the crew would of course be unable to verify this unless in contact with a secondary radar equipped unit. Irrespective of this, in the case of a serious emergency, RAF training recommends that 7700 is selected, if no other code was given after making contact with an ATC agency.
The reason no-one has given you a precise "slowing down" distance, from an IP to a landing point, which is what you appear to demand, is that this distance varies markedly because it depends on many factors.
This has little to do with the maximum physical capability of the aircraft to slow down (something often demonstrated by display pilots at airshows; a point I made in my previous post but was obviously lost on you). Instead, it depends on other factors such as the terrain, the prevailing weather conditions, the difficulty of finding the actual landing point and tactical considerations. If it is a very obvious landing point, the weather is good, the crew identify it from a long way off in good time, and there are no tactical reasons, the crew might choose to maintain higher airspeed a little longer than in adverse conditions - but 160 kts? Never.
The distance planned on paper prior to the flight might be a couple of miles, sometimes considerably more, sometimes a little less. Make no mistake, in poor, marginal VFR weather, it certainly is totally impractical to rush in at 160 kts to a distance of half a mile, especially having slowed considerably below cruise speed before the coastline was reached, as the yachtsman's evidence indicated. I believe the crew slowed down approaching the coast (as per normal SH training and doctrine) merely because of deteriorating weather, not because they were taking part in a homing trial and trying to land on the Mull using a DME.
Regarding lecturing me on passenger comfort whilst flying helicopters - how many times have you flown a passenger carrying helicopter? Not once. I've made a career out of it.
The initial point / feature that this crew would undoubtedly have used was at sea level, i.e. some point on the coastline. Becoming visual with the coastline would have been their number one priority, not looking inside at a trial fit DME whilst approaching high ground at high speed in poor weather below cloud!
Regarding the significance of the "emergency" selection found on the co-pilot's intercom box. You appear to misinterpret what this does. On ALL the aircraft types I've flown, this facility is NOT designed to select an emergency radio or a frequency for external comms. What it does is to allow the user to restore his voice communications, on intercom, with the rest of the crew, if his own box fails. Usually the "emergency" selection "borrows" the amplifier of another intercom box, or simply connects the user to it; for example the co-pilot's headset becomes connected to the pilot's side box. What other facilities are available in these circumstances depends on the actual aircraft comms design. I can't help you with that, it's an aircraft specific issue. Someone else here may be able to help you further.
So, the major significance of the selection of emergency intercom on the co-pilot's side, is that it indicates that the co-pilot had lost his normal intercom. Not that he made the selection to speak to an outside local ground agency / mobile unit, while climbing towards a cloud covered hill at 160 kts in an effort to land on it.
I previously told you this some years ago, when you first began visiting this forum. I think it was actually the main content of the first PM you sent. Again, you have either forgotten my reply, completely misunderstood it, or have simply chosen to ignore it.
I also recall you were quite polite in those early days, until the answers I gave didn't fit in with your own theories. When I said I didn't know the answers to some of those questions you accused me of being part of an "old boys cover up"! If there is a cover up I'm certainly not part of it; in fact the very opposite.
Why do you so rudely and patronisingly make a point of rebuffing honest answers that don't fit in with your own theories? My answers cannot be, in the main, constructive to your own theories, because you base them on your incomplete understanding of how helicopters fly and how they are operated, especially in the SH role, and what the relevant role was.
As for my "less than constructive spin"... Walter have you ever read your own posts, let alone mine?
At least my answers ARE based on actual RAF SH experience as a pilot and SH instructor, some of it in NI, not stuff I have read in books or simply made up, based on partial understanding. If I don't know the answer to a question you have asked, I have simply told you so, and given the reason.
I have yet again attempted to give honest answers to the points you raise, but why I still bother is a moot point, as all you ever give is back is far less than constructive.
Good luck with your UK meeting.