TruTrak Altrak VS - Manual (Page 6)

TruTrak Flight System 4 Altrak Installation & User Guide
January 2009 8300-014 Rev B
Basic Altrak Operation
Once the aircraft is at the desired altitude, and trimmed for level flight, the altitude hold can be engaged.
Pushing the
ALT button will engage the Altitude hold. If in severe turbulence or when the aircraft is out of trim
and the servo may run out of torque, in this case the current altitude and the selected altitude may be
different. When the difference between the current altitude and the initial selected altitude is more than
approximately 50 feet the light in the switch will flash, rapid flashing of the light for below altitude and slow
flash of the light for above altitude. If an out of trim condition is suspected, disengage the altitude hold, re-trim
the aircraft, and re-engage the altitude hold. If turbulence is the cause for the altitude departure the Altrak will
fly back to the desired altitude automatically.
Changing the desired altitude can be done by simply disengaging the altitude hold, flying to the desired
altitude and re-engaging by pushing the
ALT
button. If on a long flight setting the barometer to the local
setting will result in a difference in indicated altitude and the altitude selected by the Altrak. To correct the
altitude error, disengage the altitude hold, fly to the new desired altitude and re-engage the altitude hold.
If the optional trim sensing pitch servo has been purchased, the Altrak will enunciate the need to trim the
aircraft, with a rapid flash of the light in the switch for the need to trim up, and a slow flash of the light in the
en
unciator for the need to trim down. If the Altrak is coupled with a Digitrak / Pictorial Pilot, the Altrak can only
be engaged if the Digitrak / Pictorial Pilot are engaged. When the control wheel switch is pushed, the Digitrak
/ Pictorial Pilot will enter control wheel steering mode as normal, but the Altrak will remain engaged and
holding altitude while the pilot manually flies the aircraft to the desired track. Upon release of the control
wheel switch the Digitrak / Pictorial Pilot will re-engage and synchronize to the track being flown at the time,
and the Altrak will remain engaged throughout the maneuver. It should be noted that the Altrak will lose some
altitude while the aircraft is turning. The altitude loss cou
ld be as much as 50 to 100 feet depending upon the
bank angle. The Altrak will recover the lost altitude on it's own after the turn is completed, or if the aircraft is
in a sustained turn.
Because Altrak does not receive bank angle information, it will lose some
altitude in turns. If the bank angle is less than 30 degrees the altitude loss will
be less than 50 feet, for this reason it is recommended that the bank angle be
kept below 30 degrees.