Originally Posted by
Unknown Rider
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.
Ok, I'll try again. My point was that there seems to be a normalization of doing descent/decel planning to be stable right at 500' if VMC. If everyone just targeted stable at 1K instead, you wouldn't have this video. The complaint I hear about doing this is "you're slowing down too early!"
If 120kts (Vapp) at 1K instead of 180kts at 1K, what's it really cost in time? Assuming both situations would be 120kts at 500', you have 500' to play with. Also, making the math really simple, I'm assuming an instantaneous decel from 180kts to 120kts right at 500'.
Three degree glide path is 314'/nm, so 500'=1.6nm. Compare the difference in time to travel this 1.6nm at 120kts (48 sec) vs 180kts (32 sec). I just don't get the cavalier attitudes I see regarding stable approaches and the willingness most display to say "close enough". All over less than 16 seconds?... If you routinely target stable at 1K, you've at least got a fighting chance to make it with the Mempho 30kt tailwinds. Fly however you want, it just doesn't make any sense to me.