Sorry to dig this back out again, but I was pondering on it again today.
Would it be reasonable to generalise this in the following way (differentiating between 'settling with power' & VRS):
'Settling with power' is more likely to occur when hot, high,
heavy. These factors are more likely to lead to a situation whereby on an approach, with loss of translational lift, you develop an increasing ROD (if you don't regain TX lift), with power applied (probably over-pitch & low rpm) and low airspeed. This
perhaps turns into fully developed VRS if there is sufficient height for ROD to develop before ground contact, but even without VRS developing this could be misinterpreted as actual VRS
(therefore the heavier the more likely)
However, to enter VRS without the cause being a lack of power induced ROD (perhaps just a bad out of wind approach etc), one needs a higher ROD when heavier because the speed of the downwash from the disc is greater and therefore you need a higher ROD to catch up with it... (going against the blade root stall etc... explanations that I was taught, but apparently true according to the real test data given by Nick, Shawn etc....) This is therefore more likely to occur accidentally at a lower AUM, given the required ROD may be less...
Does that sound reasonable as I often get asked on this because there is so much confusion between VRS and 'Settling with power'. Or is it me thats confused
Aucky