Dead Reckoning

What is dead reckoning?

Dead reckoning is when we as pilots calculate our heading making an allowance for wind (either in flight or pre take off), and then fly that heading at the speed we nominated. Dead Reckoning is used at the pre-flight planning stage to estimate wind correction angle and headings to fly.Pure dead reckoning in flight is rarely used as it makes no reference to ground features along the route (which enable the pilot to accurately fix position at a point in time). In flight it is most useful when flying over large expanses of water or featureless land such as a desert. It could also be used in circumstances of radio navigation indicator failure whilst flying IMC.

Dead Reckoning Calculations

Using The Circular Slide Rule

Quick Tips

Always use the dot down method (described later).
Always use the Speed scale closest to your True Airspeed.
Groundspeed can NEVER be greater than TAS + Wind Speed (Pure Tailwind).
Groundspeed can NEVER be less than TAS - Wind Speed (Pure Headwind).

The CRP can be used to calculate dead reckoned headings and groundspeeds in the following manner.

Example Content

Web References

Check Your figures with our Dead Reckoning Calculator