IRIS A-10 radio altimeter

[TacomaSailor]

The pilot handbook Section 2 HUD Detail WD-1 and WD-2 references the radio altimeter and shows the Radar Altitude being displayed on the right side of the HUD.

When I switch my HUD to WD-1 or WD-2 all I see is the baro altimeter in the HUD - it always reads exactly the same as the analog gauge. As I fly low over very hilly terrain, with lots of arroyos, canyons, valleys, around Durango Colorado the HUD altitude display does not track the terrain as I would expect rad alt to do.

I find nothing in the manual about turning radar on/off - what am I missing?

What do I need to do to get the rad alt to track the terrain??

I am trying for help here since the IRIS forums are closed.

[fox18delta]

The real world A-10 didnt get radar alt unilt well into its service life. I seem to remember a similar thread in the Iris forum...can't quite remember, but the outcome might have been that they chose to model no rad alt. In any regard, the hog was flown with no rad alt and no autopilot for many, many years.
So have fun with the Baro alt..real world hog-drivers did for years :-)

[TacomaSailor]

the IRIS documentation shows how to use the WD-1 and WD-2 mode with rad alt to aim weapons but the only way I can get the rad alt to display in the HUD is turn it to EXP

I guess their doc didn't keep up with their modelling

While experimenting with HUD settings - several times the HUD turned it self off and would not turn itself back on no matter what I did. I had to reload the AC and restart all systems to get the HUD back.