Trio Avionics Pro Pilot - Manual (Page 44)

Trio Pro Pilot Manual 3.8
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EFIS GPSS and GPSV Guidance
Compatible EFIS systems provide an ARINC 429 data signal that enables the GPSS and GPSV
functions of the Pro Pilot. This allows the EFIS heading and altitude bugs to control the aircraft through
the autopilot.
 If the EFIS is sending the appropriate ARINC 429 commands, the blue GPSS and GPSV LEDs
will illuminate.
 If the autopilot is receiving only valid GPSS data, only the GPSS LED will illuminate.
 The
H MODE must be set to the TRK (Track) mode, and the TRK LED must be illuminated for
the autopilot to respond to the EFIS commands.
 The EFIS may provide flight plan data for en route navigation as well as approved approaches.
Operational procedures and interface controls on available EFIS systems vary widely. Most will provide
means for heading and altitude control as well as GPS navigation. It is therefore necessary for the pilot
to become proficient in the operation of the EFIS system before attempting to use it with the autopilot.
 EFIS systems obtain their navigation information from either an external or internal GPS system
incorporated into their product. The performance of the autopilot will be directly affected by the
quality of the navigation data that it is obtaining from the EFIS.
Often, the aircraft will have more than one navigational signal source available to the Pro Pilot.
 Many EFIS systems get their navigation data from an external GPS receiver. It is advisable to
install a means to connect the autopilot data inputs to each alternative signal source provided.
 It is common to have a handheld backup GPS receiver for use in the event that the primary
receiver fails.
 In the event that the primary GPS or EFIS failure, the Pro Pilot can be quickly connected to the
alternate signal source by use of a simple switch.
 Some example switch arrangements are shown in the wiring chapter.
Unusual Conditions
Although it is impossible to list all the various failure modes that can occur with multiple complex
systems, some points are worthy of note.
1. Under any condition, turning off the Pro Pilot servos positively returns control of the aircraft to the
pilot. This can be accomplished via the servo buttons on the face of the bezel, the remote
autopilot disconnect switch, or by removing power from the autopilot.
2. Selecting the CRS or INT mode on the autopilot positively disconnects the autopilot from the
ARINC inputs, whether sourced from the EFIS or GPS receiver.
3. If there are multiple ARINC or RS-232 sources available, installing a selection switch allows the
Pro Pilot to independently access each source. If the primary signal source fails, the pilot can
quickly select an alternative such as using the data signal from a portable GPS receiver.
Example Approach Scenario
For purposes of illustration, assume we are cruising in the en-route mode, the Pro Pilot is using the
ARINC 429 data for roll steering commands and is in altitude hold mode at 4,500 feet. The destination is
Palomar Airport in Carlsbad, California (a sample approach chart is shown below).
In this case we are using a Garmin 400W or 500W series WAAS receiver which is approach certified.