190-01115-01 G3X™/G3X Touch™ Avionics Installation Manual
Rev. AV Page A-7
14)
Airspeed Gain
Tuning
The autopilot should now be performing very well in all lateral modes and vertical
modes with the exception of IAS mode.
Now we will tune the Airspeed Gain. The sirspeed gain depends on the pitch servo
gain for controlling the pitch servo. The airspeed gain is the gain that is adjusted to
get reliable performance in IAS mode.
Place the autopilot in IAS/ROL mode commanding a bank angle of zero and an IAS
speed that roughly allows the aircraft to hold altitude for the given power setting.
Remember to stay below the maneuvering speed of the aircraft (V
A
).
To tune the airspeed gain, allow the aircraft to settle in its steady state, then use the
control stick to over-power the servo and displace the aircraft from the desired
airspeed. The pilot should pull or push the stick to up or down for roughly one-two
seconds to establish a new airspeed, and then release the stick.
After releasing the control stick see the AP response by watching the control stick
and airspeed indicator. The aircraft should return to the desired airspeed without
being too aggressive or lazy.
To increase the aggressiveness of the airspeed response, increase the airspeed
gain.
To decrease the aggressiveness of the airspeed response, decrease the airspeed
gain.
15)
Full Autopilot
Checkout
The autopilot should be fully tuned at this point. The pilot should exercise all
autopilot modes and transitions and verify acceptable performance.
If performance is found not to be acceptable return the previous tuning steps.
Remember, turn PIT/ROL first, then proceed to tuning the secondary VS and IAS
modes.
If you cannot get your autopilot performing acceptably, first gather data by flying the
aircraft for 1-2 minutes in the autopilot mode where you are experiencing
unacceptable performance while logging data. Then email your log file to
g3xpert@garmin.com
and we will assist you in turning your aircraft for optimal
performance.
Table A-1 Flight Test Outline
Task Description
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