Trio Avionics Pro Pilot - Manual (Page 18)

Trio Pro Pilot Manual 3.8
18
Chapter 4
Preflight Power Up
This section discusses what must be accomplished when “powering up” of the Pro Pilot, items to be
checked and adjusted, and a flight example
On power up the Pro Pilot will briefly display the logo screen. This will be followed by a screen
requesting verification of the current field elevation or altitude.
Note: The TRK LED is illuminated after the GPS signal is acquired and the H NAV servo is not activated
(“H” LED is not illuminated). The aircraft roll control (ailerons) should be free and clear indicating
the servo is disconnected from the control system.
A preflight check on the Pro Pilot at this point would be to engage the servo by pressing the H NAV
pushbutton momentarily and noting that the “H” LED illuminates. The servo is now locked to the control
system. Using the control stick or yoke, the pilot should intentionally force the ailerons to their extreme
positions to verify that the slip clutch on the servo will allow the pilot to continue to fly the airplane in the
event the servo malfunctions.
If this check is satisfactory the H NAV button should be pressed again to disconnect the autopilot from
the controls. Verify that the LED is not illuminated and the servo is not engaged for takeoff.
Since the GPS is not yet powered up, after about 7 seconds the display will show the NO GPS message.
The pilot now applies power to the GPS unit that is connected to the Pro Pilot and programs the GPS
flight plan. On GPS power up, the display on the Pro Pilot may show navigation data momentarily on the
display, as some GPS receivers will send sporadic GPS data. Typically, the NO GPS message will
return as this data transfer ceases.
When the GPS receiver attains satellite acquisition and lock, the Pro Pilot will display the power up
default screen previously illustrated.
Some GPS receivers, even though they have obtained satellite lock, do not put out valid NMEA or
AVLINK data until a flight plan or “GO TO” waypoint is entered or a preset groundspeed is attained
(usually 2 to 5 knots). In this case either the “NO GPS” message or the “NO FPLAN” message will
be displayed.
Some GPS receivers’ output data are capable of providing ground track and groundspeed information to
the Pro Pilot after satellite lock, even before a flight plan is entered. The Pro Pilot will detect this and
provide the pilot with a modified CRS mode capability.
In this mode, manual transition to the TRK or INT mode is inhibited and NO FPLAN is displayed on the
screen. In the NO FPLAN mode the pilot may use the autopilot CRS mode to fly a selected ground
track. Once a flight plan has been entered the TRK mode is automatically selected.
The flight plan is now entered and activated in the host GPS unit. As the first “TO” waypoint
becomes active the Pro Pilot will display the parameters associated with navigation to that waypoint.
A check should be made to verify agreement between the data displayed on the Pro Pilot and the
host GPS system.
Important: If all of the above actions cannot be properly achieved, turn the Pro Pilot off
and do not attempt to engage the autopilot in flight. If there is any indication of an
aileron control system problem do not fly the airplane until it has been corrected.