An approach computer device is provided for an aircraft approaching a landing field to enable the pilot to have before him during the approach a device which shows the distance to the landing field and, correlated with that distance, the altitude at which the plane should be flying at such distance. The distance to be flown is set as the plane passes over the final approach fix from which the plane is to approach the field at a constant rate of speed. The device is calibrated to provide a constant rate of descent, such as 500 feet per minute.
