CHAPTER 4 REFERENCE GUIDE
Page 4-6
091-00027-001 REV A Evolution Backup Display Pilot’s Guide
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091-00027-001 REV A
Two minutes after detection, a FREE GYRO MODE annunciation will be presented across
the HSI, indicating the heading system no longer can be aligned with magnetic north.
Some precession of the heading is possible, especially during abrupt maneuvers. If the
condition persists for four more minutes (six minutes total) the attitude and heading
indicators will be removed and replaced with red X indications. When the conditions
causing Free Gyro Mode are no longer present, attitude and heading indications will be
restored after an automatic AHRS reset.
4.1.5. Degraded ADAHRS Performance
For Degraded ADAHRS Performance, reference the following:
• Sections6.1.Pitot/StaticSystemBlockage
• Sections6.8.In-FlightAHRSReset
• GeographicLimitationsin the AircraftFlightManualSupplement that was
installed in the aircraft with your EBD.
091-00027-001 Rev A EBD Pilots Guide V&H .indb 7 8/27/14 8:51 AM