CHAPTER 4
REFERENCE GUIDE
EFD1000 E5 Pilot’s Guide
Page 4-6
091-00086-001 ( )
Just like other compass systems, the accuracy of the fluxgate is affected by its location
on the airframe. Ferrous metal structures, electrical fields produced by motors, pumps,
wiring, magnets in cabin speakers and other airframe-related sources of interference
either constant or momentary (i.e. operating an electric trim motor, windshield heat,
pumps, etc) can all affect the accuracy of the compass. The installer can compensate
for much of this interference when calibrating the RSM, but some effects cannot
be eliminated. Proper location of the RSM during installation is critical to the AHRS
performance and accuracy.
Furthermore, all magnetic compass systems are susceptible to local disturbances in the
earth’s magnetic field (some of which are shown on aviation charts or by NOTAM) and
will exhibit degraded performance when operating in extreme northern and southern
latitudes close to the earth’s magnetic poles.
4.1.4. Free Gyro Mode
When the E5 Dual EFI system detects that the horizontal component of the earth’s
magnetic field is no longer strong enough to provide reliable heading data, it will detect
the condition and annunciate that the heading system is no longer slaved to magnetic
north. If the condition persists, attitude and heading indications are removed.
While the condition can occur at greater distances, it is most likely to be observed
within 750 nautical miles from the magnetic poles. In the Northern Hemisphere, this
equates to operations in the Arctic Islands found north of continental North America.