Originally Posted by
av8rmike
I'm not looking at it from a VSI perspective. Just highlighting the time difference from 1K to touchdown if stable at 1K vs stable at 500'. If that didn't clear up the confusion, I'll be happy to show my math. Sorry for not being more clear about my point.
Well you're talking about distance down, not distance over the ground so you have to use fpm. The typical approach is 750 fpm which equates to 12.5 fps. Therefore 500 feet down would equate to 40 seconds at 750 fpm. At 1000 fpm, 500 fpm equates to 30 seconds. At 2000 fpm, 500 fpm equates to 15 seconds.