Attitude And Heading Comparison Monitors - BOMBARDIER LEARJET 40 Pilot's Manual

Pilot's Manual

ATTITUDE AND HEADING COMPARISON MONITORS

The attitude and heading comparison monitors are functions within
the IC-600s that compare the displayed data with the cross-side or sec-
ondary source data, depending on system reversionary status. Annun-
ciations are provided to the crew if the attitude or heading on both sides
differ.
The attitude comparison function is made of two monitors, the roll
comparison monitor and the pitch comparison monitor. If the pitch
data displayed on each side differ, the pitch comparison monitor trips
and the PIT annunciation is displayed. The comparison threshold fig-
ure for the pitch monitor is 5°. Similarly, if the roll data on both sides
differ, the ROL annunciation is displayed. The comparison threshold
figure for the roll monitor is 6°. If both the roll and pitch comparison
monitors trip, the ATT annunciation is displayed. If the heading com-
parison monitor trips, HDG is displayed. The normal comparison
threshold figure for the heading monitor is 6°. However, if the dis-
played roll information is > 6°, the heading comparison threshold fig-
ure is increased to 12°.
All comparison monitor annunciations flash for 10 seconds on activa-
tion and then remain steady. These comparison monitors provide an
extra safeguard to alert the cockpit crew in the event of any failures af-
fecting the attitude or heading data displayed.
Other annunciations for attitude and heading which are displayed on
the PFDs, not associated with the comparison monitors, are:
ATT FAIL and HDG FAIL. These red annunciations are displayed on
the affected side's PFD whenever the heading or attitude display from
that AHRS has failed. If an AHRS fails or both primary and auxiliary
power supplies to an AHRS fail, both the red ATT FAIL and HDG FAIL
annunciations are displayed.
ATT1/2 and DG1/2. These annunciations are displayed on the PFDs
and indicate to the crew which AHRS is the source for the attitude and
heading data on the display. If the onside AHRS is the source of display,
the annunciation is white. If AHRS reversion has been performed, the
cross-side PFD annunciation is amber. There are no crew actions
required for these annunciations.
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PM-132A