Originally Posted by 212man
I'm very surprised to hear of 1000 ft calls caused by overflying another aircraft - I'd have thought that a spike like that would be filtered out (again, is for the helicopters I've flown)
I was interested because somebody asked the same kind of question on a very different forum.
But unless you deliberately turn off the rad-alt ... think of slowly overtaking another aircraft below you on the same airway, same track, with the usual 300m vertical separation.... the "1000ft" call suddenly made sense to me!
Anybody else?
Originally Posted by Fullblast
Are you all talkin' about radar-alt or radio-alt?
Same difference, really.
Just grabbed a couple of manuals and books off the shelf.
Both British and French manuals refer to "radio-altimeter" or "radio-altimètre".
Original American literature refers to it as a "radar altimeter".
Strictly speaking it's radar - it measures a range.
But it's a rather special kind: CW FM radar ('continous-wave' 'frequency modulated' if you want to get technical...).
So it's just a matter of terminology and usage. But we're definitely talking about the same thing.