Walter, I'll try to answer this question (despite your totally unwarranted invective last time I answered a question you posed; I would be grateful if you would refrain from this in future). Cazatou cannot answer with any certainty because he has never been a helicopter pilot and has no experience of the appropriate SH SOPs, rules or limits.
It isn't / wasn't normal to set a radalt bug to minimum for a landing in bad weather (I assume by 'minimum' you mean zero height, or close to it, depending on the individual aircraft installation). That would be rather like a parachute that opens on impact. It is normal to set the bug (to an SOP height) above ground level, whatever the stage of flight. This would have been covered in Chinook SF SOPs. It was normal during my time for the Handling Pilot (HP) to set the bug in transit to the minimum authorised transit height and the Non Handling Pilot (NHP) to set his slightly below the minimum authorised transit height, up to a maximum of 50 feet less. It is normal for the radalt needle to "flick" at low level, causing the HP's warning light to go on and off, but a steady warning would alert the crew that the aircraft was operating below the minimum height and the aircraft would be climbed to cancel the warning.
For an approach, 50 feet was an appropriate setting. Once the aircraft was below that, it was common to re-bug to a low hover height, again dependent on the actual aircraft installation, or a suitable height to keep an underslung load just clear of the ground. It must be stressed that the aircraft would be at very low airspeed, say 10 - 15 kts at this stage, certainly not the high speed at which this aircraft impacted.
I must stress that these figures are taken from my copies of SH SOPs, but not SF SOPs, which may be slightly different. If they were, someone's memory may be jogged to correct them.
Now, in return, please answer my own unambiguous question (now probably the fourth or fifth time of asking):
Walter, WHY do you NOT begin a separate thread on your theory? You have always totally ignored this request in the past. Please do not do so this time.