Rainboe
Get it clear everybody, you CANNOT judge speed or rate of descent from the cabin.
I think you may have misinterpreted my posting about RoD or I wasn't clear enough.
My point is that I cannot judge groundspeed at all, I get no sense of an approach being faster or slower, even though there must be quite a difference in aircraft types, weight, wind etc. All approaches to landing tend to be perceived as being the same by my senses.
I can't judge RoD either, in terms of 000 of feet per minute, but nearer to the ground (say 5-6,000 feet or less, with a clear horizon) due to the deck angle and the rate the scenery is growing, I find that I get a sense of normal (again, probably varies quite a lot in actuality) or unusual, e.g. LCY feels (or should I say more correctly looks) very different to LHR.
PPL training/VMC flying is nowhere near the standard of professional training or flying, but it does require the development of a certain amount of ability to recognise a visual picture and in particular reasonably small differences in pitch angles.
I'm not really interested in arguing the point, but more in exploring what (to me at least) is an interesting paradox, probably partly explained by retinal depth cues and disparity, whereas there is no motion parallax as the pax can't see through the front window, so reducing the ability tof the brain to make inferences from the relative motion of objects, e.g. the threshold, or buildings.
Again, to be clear, motion parallax would not help to gauge airspeed, but it might provide a coarse sense of 'faster' or 'slower' is one was used to the environment.
(Of course one needs to remember that we are all unique, so my perceptions may be different to other peoples and perceptions are not reality.)