Radar Altimeter (RDA) is an avionic device that is used to measure the distance (or the Above Ground Level (AGL) altitude) between an aircraft and the terrain presently beneath it. The Duke B60 and Duke Turbine from RealAir Simulations are both equipped with a piece of the instrument in their cockpits.
After an AGL altitude is selected, the DH (Decision Height) indicator of the RDA on the Duke B60 or Duke Turbine will lit up when the aircraft is within 100 feet below the set point, and turn off when the 100 feet range is passed. The corresponding FIP Duke Shared RDA I developed for the two aircraft was designed and programmed in this manner.
However, a new user, Ken, wrote to me recently saying that the DH indicator on the real RDA doesn’t react this way. Continue reading