Originally Posted by loudgarrettdriver
Remeber this is called a PDP. A VPD is shown on the plate.
Take 10% of the (HAT) subtract it from time listed on the plate.
Ex. Time on the plate is 2 minutes. (HAT) is 400ft.
10 into 400 is 40. Right. Now- subtract 40 secs from 2 minutes which gives you 1 minute 20 secs. At 1:20 if you don't have the vis go missed.
This is for a 3 degree glide slope.
Call it whatever you like, the same principles apply. (I think you meant VDP, not VPD.
)
The technique you give was cited above, along with its other major limitation - - it's only "accurate" for 120 Kts groundspeed.
[EDIT: wrong site
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