User Guide

Series III Avionics
Pilot's Guide
Page 24
If a system failure occurs in any mode, the
annunciation FAIL appears in either the upper or
lower line of the display. The system is not usable
in this condition.
Barometric altitude is indicated in lower line of
display when the MODE SELECTOR is in TST
mode. This is the altitude that will be encoded into
the transponder output when operating in an
altitude-reporting mode (ALT or VFR positions of
FUNCTION SELECTOR).