Trio Avionics EZ Altitude Control - Manual (Page 21)

21
ALT
HOLD
MIN
AS
LIMIT
under autopilot control, the pilot may adjust the rate by simply
turning the encoder knob. The aircraft will then respond to that
vertical command rate.
It must be noted that soon after a climb or descent is initiated, the
screen will likely flash a warning that the aircraft is out of trim. If
the climb or descent will be of significant duration, the pilot must
adjust the aircraft trim and throttle settings as required. The trim
message will alternate with the normal “VS” message. (Note: If
the out-of-trim condition is large, the commanded vertical speed
may not be attained and there may be some hunting or surging of the system.)
NOTE – The vertical mode has a separate gain term from the ALT HOLD mode in the
EZ-2 and EZ-3 systems. If the aircraft does not achieve the commanded vertical rate,
and/or excessive out-of-trim alarm messages are experienced, the vertical gain may be
set too low. To adjust the gain in simply press the encoder knob for 3 seconds (while in
the “VS” mode) until the setup menus appear. Adjust the gain in 5 unit increments until
satisfactory performance is obtained. The lowest gain setting that gives satisfactory
performance is the best setting.
If the gain is set too high, there may be excessive excursions when engaging the VS
mode while in a high rate of ascent/descent climb/dive.
Once the destination altitude is reached, the pilot may simply
push the LCD switch to enter the “ALT HOLD” mode, and the
system will capture the reference altitude at the moment that the
switch was pressed. Because of the aircraft dynamics, it will
overshoot the altitude slightly and smoothly return to level flight
as it settles onto the referenced altitude.
As the aircraft transitions to a climb/descent and then back to
level flight it may be necessary to adjust the aircraft trim and throttle settings again to
maintain desired flight parameters.
8.1.2 Minimum & Maximum Airspeed Control
The EZ-2 and EZ-3 systems incorporate an airspeed sensor in the electronics module.
This allows the system to constantly monitor airspeed to avoid stalling or over-speeding
the aircraft while under autopilot control. The proper minimum
and maximum airspeed limits are set by the pilot, using the setup
menu. These limits must be individually determined by the
aircraft type (giving full consideration to stall and Vne speeds)
and the pilot’s preferences. (See paragraph 8.1.3). Once set up,
these settings will remain in nonvolatile memory.
Let’s assume that the aircraft is in the “VS” mode and a climb rate
of 500 fpm has been entered. When the LCD switch is pressed,
Note: The TRIM message will not appear immediately after a trim imbalance is
detected. The system is designed to delay this message so that it doesn’t appear
in normal turbulence or other short term excursions. Likewise, when you adjust
the trim setting on the aircraft to normal, it may not immediately disappear.
Because this function is damped for smooth operation it may take a while to
remove the warning. In the ALT HOLD mode, a quicker way to accomplish this is
to press the LCD switch to return to the READY mode, trim the aircraft and then
reengage the system.
TRM
UP