Visual Descent point (VDP)

A defined point on the final approach course of a non-precision straightǦ in approach procedure from which normal descent from the MDA to the runway touchdown point may begin provided adequate visual reference is established. 

If not equipped to identify the VDP, fly the approach as if no VDP was published. 

When a VDP is not published you can use this formula to calculate it: 

VDP (in NM from threshold) = HAT/300, or 10% of HAT = seconds to subtract from time to MAP