chugalug2 <<... an IFR letdown in IMC.... >>
Not with my understanding of the weather it wasn't - have you not read my numerous posts on the weather? At the level of the LZ, the "IMC" would typically have only been 10 metres or so off the slope and intermittent at that - they were not in it until the last seconds.
The basis of my scenario is that visual judgement of the closing range would have been difficult - if they had had an accurate measurement of range continuously available, then they should have been down to a speed at which they could wave off safely if they could not see the ground clearly enough at the threshold of the LZ - I do not believe that a responsible crew would have gone in there without believing that they had accurate range - I believe that they thought they had but were misled wilfully or by error on the part of the personnel on the ground.