bose-x
Due to the importance of this I have just checked it with a Honeywell/Garmin avionics distributor technican who I know knows the stuff, and unfortunately you are incorrect both on the GNS430 and the KLN94B.
The displayed altitude is derived solely from GPS satellite signals.
(The GNS430 can display the altitude encoder output in one of its maintenance pages but that's it)
The purpose of the altitude encoder is solely for RAIM checking. RAIM checking is a requirement aof an IFR approved GPS. The GPS compares the altitude encoder output (corrected for the QNH which on the KLN94 you enter manually) with the GPS-derived altitude and if there is an error exceeding a certain figure it will flag a RAIM warning.
The GNS430 should have a QNH setting too.
So, if the static system failed, the GPS altitude would still work the same. You would get a RAIM warning though.
Last edited by IO540; 8th January 2004 at 19:01.