Trio Avionics EZ Pilot - v 1.9 - Manual (Page 23)

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Note: In the above example, it might be expected that the EZ Pilot would immediately begin to turn
toward the first programmed waypoint when the servo is engaged. However, it must be remembered
that the flight plan establishes the courseline between the departure WPT and the first destination
WPT. Therefore, the autopilot will fly to the courseline and then turn toward the WPT.
To proceed directly to the WPT from present position, the pilot would need to utilize the “Direct To”
feature of the GPS receiver. The EZ Pilot would then track direct to the desired WPT.
NO GPS TURN
[--------X-------]
5.2 Flying to a Courseline (DTK) or GOTO Waypoint
If this is the first flight with the EZ Pilot, the in-flight adjustment of Servo Neutral
must be accomplished (see section 7.7).
After take off, and at a safe
altitude, select the flight plan on
your GPS and press the SERVO
POWER pushbutton momentarily.
Note that the SERVO LED is now on and the autopilot has control of the aircraft.
One of the design features of the EZ Pilot is its ability to find the desired course (DTK) and track
to it regardless of where the airplane is heading when the autopilot is engaged. In an extreme
example, the plane might be flying 180 degrees away from the GPS routing and the EZ Pilot will
bring the aircraft around smoothly to the proper groundtrack and pick up the programmed DTK
(zero the cross track error). In the example shown above, the pilot engages the servo after
takeoff and climb to safe altitude. The EZ Pilot then intercepts and flies the course line (DTK) to
the first waypoint.
During the flight on this leg some other navigation parameters are available
for review, such as
estimated time to the waypoint (ETE or ETe). Pressing the DISPLAY switch presents this data.
Pressing the DISPLAY button again shows RNG (distance) to this waypoint. The DISPLAY
button is pressed repeatedly until GS or WPT is back on the display, since they are probably
referred to most often in flight, or the pilot may engage the scan mode to see all parameters (see
Sec. 3.2.9.10). Additionally, the upper right display field can be programmed to display any of
the GPS derived data as described in paragraph 3.2.13.
5.3 Loss of GPS
With the GPS antenna placed where it can “view” all
of the satellites available, it is unlikely that a loss of
reliable GPS signal will occur. However, if the GPS
receiver is a handheld device without an external antenna (especially if it is being used in the
cockpit of a metal airplane) it is possible to experience a loss of GPS signals. In such case, after
Note: As a safety feature, during the
takeoff roll, the EZ Pilot checks the
status of the servo. At 25 knots GPS
groundspeed, it will automatically
disconnect the servo, allowing free
movement of the ailerons. This is a
backup feature only and should not be
relied upon to replace a necessary
preflight checklist item. This feature
relies on a proper GPS signal being
received and will not function properly
if the GPS is not active and providing
data to the autopilot.