TruTrak Digiflight II Instal Manual - Manual (Page 20)

TruTrak Flight System 18 DigiFlight II Series Auto Pilot Installation Manual
December 2009 8300-008 Rev D
tains a built-in magnetometer which is used to maintain gyro centering and slaving for the built-
ilot in case of GPS loss. Magnetic calibration operation should be done on a day when the winds
h the
Magnetic Calibration
The DigiFlight II autopilot con
in Electronic DG of the autop
are relatively calm, so that air is still and heading and ground track are approximately the same in all directions. The operation
should be deferred until such flight conditions exist. For this operation the autopilot will first fly north, then east, then south,
then through west once, then trough west again, and finally will hold west. Prior to the calibration sequence, fly the aircraft to
an area where this can suitably be done. Verify that the autopilot is receiving GPS properly (note the flashing “*” in the
display). Engage the autopilot in its normal tracking (TRK) mode and engage the altitude hold at an appropriate altitude.
Once the autopilot is engaged, press and hold MODE until the setup screen appears. Press the ALT button to cycle throug
setup screens until MAG CALIBRATE? Appears on the screen. Rotate the knob to select Y (yes) and press ENTER. The
autopilot screen will announce “CALIBRATING… TURNING NORTH”. It will fly to a ground track of 000 degrees, then
say “HOLDING NORTH”. For approximately ten seconds, the unit will obtain data from the magnetometer for this heading. It
will then announce “TURNING EAST”, then “HOLDING EAST” and so on, until it has flown a ten-second leg in all four
directions, ending up flying towards the west. Having completed this operation, the display will change to “CALIBRATION
DONE” “PRESS ENTER”. Confirm the calibration sequence by pressing ENTER. At this point, the autopilot will revert back
to its normal flight mode with a direction selector, but the upper-left display will show HDG rather than TRK, indicating that
the autopilot is in its magnetic backup mode. This allows the mode to be confirmed in flight. Rotate the knob to select various
headings and observe the flight of the autopilot in the magnetic backup mode. If problems or inaccuracies occur with various
headings, it is possible that these problems are due to excessive turbulence or winds on this particular flight, and it may be
necessary to repeat the operation at a different time. Once the check-out of the backup mode is finished, disengage and then re-
engage the autopilot to return to normal Track (TRK) mode.