I dont know either, but when I was at the avionics shop picking up my plane
recently, there was a pressureized C-210 they had just starteding working and
let me peek inside. It had dual garmin 330 x-ponders, garmin 430,530 and an
MX20, it also had some other nifty stuff like a flight navigator and so on.


Scott Aron Bloom wrote:

Ok, Im not talking about the commercial carriers. But why would a general
aviation plane have dual transponders? Why waste the panel space? So they
go
tits up that often in flight where its necessary?

Scott