Page 47
Sub-section - 4.05
ABNORMAL PROCEDURES
FAA Approved
Original Issue: Feb 28, 2006
Hawker 850XP Pro Line 21 Airplane Flight Manual
COMPARATORS
Miscompare Annunciators
Miscompare annunciators are displayed on the PFD to alert the pilots that redundant data from
dual systems is not agreeing within limits. Attitude, heading, altitude and airspeed data are
monitored full time. Full time comparators are provided for engine N
1
, N
2
and ITT.
Miscompare annunciators are displayed in yellow, flash for 5 seconds initially and then remain
illuminated. The annunciators will extinguish when the miscompare condition is removed.
Two independent sources are required for each comparator function and the comparators are
disabled if ADC or AHS reversion is selected or either side has failed.
If miscompare annunciations are observed, the crew should attempt to ascertain which system/
component is erroneous. Use of the Electronic Standby Instrument System may assist this
process. The applicable reversionary mode for ADC or AHS will provide cross-side data for
display. No reversionary capability for engine miscompares is available.
HDG
This annunciation indicates a mismatch between the pilot’s and copilot’s displayed heading data.
Establish airplane in straight and level, unaccelerated flight.
Compare indications with the Electronic Standby Instrument System.
Determine if pilot’s or copilot’s heading display is in error.
Relevant AHS Transfer switch ....................................REV
PIT or ROL or ATT
This annunciation indicates a mismatch between the pilot’s and copilot’s displayed attitude data.
Establish airplane in straight and level, unaccelerated flight.
Compare indications with the Electronic Standby Instrument System.
Determine if pilot’s or copilot’s attitude display is in error.
Relevant AHS Transfer switch ....................................REV
ALT or IAS
This annunciation indicates a mismatch between the pilot’s and copilot’s displayed air data.
Establish airplane in straight and level, unaccelerated flight.
Compare indications with the Electronic Standby Instrument System.
Determine if pilot’s or copilot’s air data display is in error.
Relevant ADC Transfer switch....................................REV
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For Training Purposes Only