I have the utmost respect for both Nick and John and am very glad Nick took the time to point out the difference between VRS and SWP as there is much confusion out there between the 2. So much so that Transport Canada has mandated that during PPC check rides, the examiner must question the applicant on these items ( as well as dynamic roll over).
I am glad John has qualified Nick's statement about vertical descents being relative to the air mass. As someone who has been in VRS a few times (both intentionally and NOT) I can tell you that you can get into it while definitely not APPEARING to be in a vertical descent ( downwind).
Also I would like to qualify Nick's statement:
"For the record, no helicopter can experience true VRS unless it is descending nearly vertically at about 800 to 1000 feet per minute."
I do believe he meant to say, "no MODERN helicopter....."
Again from experience, I can tell you an S61 can enter this at between 300 and 500 ROD, not sure of the exact number as I was kinda busy at this point
Also, thanks Nick for the explanation about the reason why a lightly loaded helicopter has more propensity to enter VRS than a heavy one......I knew that was the case, but never knew why.