Rad Alt
 

Why are Radio Altimeters rarely seen in light Aircraft? Is this primarily down to cost or the perceived usefulness?

Would a Rad Alt at a purchase price of £600 be viewed as affordable?

I am interested to hear your views?


Regards NTB

Light aircraft are mostly flown visually - VFR - so a radio altimeter has little added value.
For IFR planes they can have some interest but there they would need to be certified, making a price of 600 quid unlikely.

Rad alt is really only used for cat 2&3 approaches, light a/c are only cat 1.(cat2&3 require a whole lot more equipment&training to use so not practical) egpws gives terrain warning, as does the likes of SD nowadays.So a rad alt is waste of time, doesn't show the mountain in front of you, IMHO

I think arelix is right, GPS systems with terrain warning are common and cheap, and as there’s no requirement for radalt apart from CAT II/III ILS there’s no need for a certified solution.

In light aircraft equiped to fly in IMC a GPS based terrain database would be a cheaper and safer solution.
Radar altimeter is not a one-fix solution it is but a small tool in the big toolbox of (predominantly) large aircraft.

CAT 2 in the USA
 

If you have double ILS systems and a RAD ALT you can fly CAT 2 approaches in the USA but that is the only practical reason for a RAD ALT in a light aircraft.

That and helping you comply with the 1,000 foot rule when held down due to bad weather and low OAT.

Well that looks like a resounding NO then.

Thank you all for your input, it looks like a Rad Alt development would not be worth while.

Regards

NTB

If you are operating a lot at low level over water a very useful addition.