Pontious
Walter, you didn't offer an answer and no one else has.
Well I will!
Picture flying in a helicopter into a LZ at night in the mountains of Norway to an approach aid consisting of five torches for the use of laid by the MAOT. On the approach the Rad Alt is useless as it is reading under the aircraft and wizzing up and down as you pass over the terrain. What would you like to see on your Bar Alt as you approach the T?
I like to see it winding down to zero not some height above sea level that I have to remember. It's hard enough flying the aircraft especially if the wind is up your chuff and bouncy, it's snowing and you are not allowed to use landing lights. Oh - and you are about to get whiteout in the dark!!
Airfields are a totally different ball game for people with less flying ability!
Ducking and running now.................
