Enter the height above touchdown, descent rate, and runway threshold into the calculator to determine your vertical descent point (VDP).

VDP Formula

The following formula is used to calculate a vertical descent point (VDP). 

VDP = HAT / DR + RT
  • Where DRP is your vertical descent point
  • HAT is your height above touchdown
  • DR is the descent rate
  • RT is the runway threshold

To calculate the VDP, divide the height above touchdown by the descent rate, then add in the runway threshold.

What is VDP?

Definition:

A visual descent point is a defined point on a straight line that can be used as an estimation for landing an aircraft.

How to calculate VDP?

Example Problem:

The following example problem outlines the steps and information needed to calculate a VDP.

First, determine the height above the touchdown. For this example, the height is determined to be 600 feet.

Next, determine the descent rate. In this case, the descent rate is measured to be 300 ft/NM.

Next, determine the runway threshold. For this runway, the threshold is .3 DME.

Finally, calculate the VDP using the formula above:

VDP = HAT / DR + RT

VDP = 600/300 + .3

VDP = 2.3 DME