Pitot/Static System Blockage - Aspen Avionics Evolution Backup Display EFD1000 Pilot's Manual

6.1. Pitot/Static System Blockage

A pitot line blockage will result in the airspeed indicator behaving like an altimeter
when the aircraft's altitude changes, and it will not respond to airspeed changes. A pitot
line blockage can also affect the EBD's attitude indication.
A static line blockage will result in altitude remaining fixed and a zero vertical speed
despite aircraft pitch and/or power setting changes. In addition, IAS indications will
be incorrect if the static line is blocked. Errors will typically be noticed during climbs
or descents. When descending, ambient pressure increases which will result in the
indicated airspeed reading more than the actual airspeed. The opposite effect will be
observed in a climb. A static line blockage can also affect the EBD's attitude indication.
Indication of an obstructed pitot system is provided for EBD when the EBD's indicated
airspeed is less than 30 KIAS (35 mph) and GPS ground speed is greater than 50
kts (58 mph), then attitude and heading instruments are replaced with red Xs and
textual annunciations to indicate their failure. In this case, an amber CHECK PITOT
HEAT annunciation accompanies the ATTITUDE FAIL annunciation. When the pitot
obstruction is subsequently removed and indicated airspeed ≥ 30 KIAS (35 mph), the
CHECK PITOT HEAT annunciation will be removed in 15 seconds. This indicates that
the EBD is performing an automatic AHRS reset in the background. No pilot action is
required to reset the system.
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Evolution Backup Display Pilot's Guide 091-00027-001 REV A
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