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.
If the indicator just illuminates within a short altitude range or only for a few seconds (during descend), the warning light will be easily missed. Moreover, the feature of the RDA is not just for approaches, but is useful in cruise flight for terrain warnings as well. This is pretty standard and is not specific to any particular airplane.
Ken suspected that the developer of RealAir Simulations might not get it right in the first place.
Based on Ken’s explanations, the Duke Shared RDA for the Duke B60 and Duke Turbine has been updated accordingly, and ended up with 6 versions in total as follows:
The two existing gauges (clean & extended) are kept to continuously cope with the responses on the B60 and Turbine (see first image).
Two new (Real) versions are added to comply with the operations found on the real Radar Altimeter as Ken described above (see second image).
Two Extra versions are further modified from the Real versions in 2) to add fun to the using of the instrument — the DH indicator will flash in yellow when aircraft height is between 500 and 201 feet AGL; and flash in red when aircraft height is lower than 200 feet AGL (see right image).
Surely these extra features are not found on the real RDA. But as Ken said, the Radar Altimeter in real world is generally an aftermarket avionics option, and it is not in great demand these days due to the advent of TAWS (Terrain Awareness and Warning System) and other more modern terrain warning systems.
However, the instrument does look cool in the cockpit, real or sim; so does the extra version.
Existing users of the Duke Shared RDA should have received the download link for the update in their mailboxes in the next few hours. If not, contact me directly via email or thru the Comments Section below.
Lastly, even though this RDA is customized for the RAS Duke’s, it is generally good for all other aircraft in FSX/P3D since it is not specific to any particular plane as the RDA does in real world.