Operating Handbook For DFC SERIES AUTOPILOTS TRUTRAK FLIGHT SYSTEMS 1500 S. Old Missouri Road Springdale, AR 72764 Ph. 479-751-0250 Fax 479-751-3397 www.trutrakflightsystems.
1 Table of Contents Operating Instructions General Introduction.................................................... 2 Mode and Data Display ............................................... 3 Controls ....................................................................... 4 Lateral Modes.............................................................. 4 Magnetic Back-Up Mode ............................................ 6 Yaw Damper................................................................
2 General Introduction The Trutrak autopilot can be defined as being an orthogonal rate system. This means that gyroscopic rate sensors are installed so as to sense motion about each of the major axes (roll, pitch and yaw). These sensors generate the fast signal responses necessary to create an autopilot with the best possible dynamic performance.
3 POWER UP—AIRCRAFT STATIONARY SEE INITIALIZING THE AUTOPILOT PAGE 9 Mode and Data Display This display normally shows operating modes and associated numerical data. It is also used to display setup mode screens and the setting of associated numerical data. When displaying operating modes, the left side shows lateral data and the right side shows vertical data. (See figure below) The upper left display TRK shows the labeled electronic DG slaved to GPS track.
4 Controls Lateral Modes Switches labeled [MODE] and [ALT] when depressed sequentially step through the respective lateral and vertical mode setup screens. When the desired setup screen is displayed, the numerical data to be entered will be underlined. The data is then set by rotating the encoder knob and entered by depressing and then quickly releasing the knob. This will be referred to hereafter as enter. Another means of entering numerical data is the sequential pressing of a [VS] switch.
5 In the GPSS mode the autopilot follows lateral steering or bank commands generated by a navigation system (EFIS or GPS). TRK+135 GPSS ALT 4500 SVS 500+ The next sequential entry screen is VOR NAV or LOC NAV, depending on which is selected by the navigation receiver. The setup screen for this mode is shown below. LOC NAV CRS 183 INTRCPT ANGLE 30 The course numerals are underlined. This means that the VOR/LOC course is to be set by rotating the encoder.
6 lateral mode will switch from LOC NAV to TRK mode. The selected track will be the same as the inbound course. The next sequential mode is LOC/VOR REV. This refers to flying the localizer or VOR in the reverse direction. Operation of this mode is the same as LOC NAV except that there will be no glideslope coupling. Magnetic Back-Up Mode The lateral modes previously described are based on GPS track being present.
7 the digital altimeter. For example, pressing enter between 4950 and 5050 will select 5000. CURRENT ALTITUDE ALT 2200 HOLD -press enterTRK 183 AH 2200 SEL 183 ALT HOLD Altimeter Sync With the autopilot engaged, the internal altimeter can only be set when the aircraft is level in the ALT HOLD mode. To accomplish this, press [ALT], once in order to display the current altimeter reading. Then rotate the encoder to set the internal altimeter to agree with the primary altimeter.
8 encoder knob once and the underlined cursor moves to selected altitude. Pressing a second time moves it to air speed and a third time returns it to direction, or after 8 seconds it will return automatically to direction. It will be observed that the airspeed will change at a constant pre-set rate from the initial value to the selected value at which point it will cease moving with no overshoot.
9 Additional Operating Instructions Initializing the Autopilot The autopilot master switch should be in the off position when the engine is started. Aircraft electrical systems can generate voltage transients during an engine start, and like other avionics systems, the autopilot should not be subjected unnecessarily to these conditions. After start up, turn on the autopilot master switch and hold the aircraft stationary as the internal gyros are initialized.
which time the words GYRO SET will be displayed. MAG*180 ALT 1350 GYRO SET Engaging the Autopilot Since the autopilot synchronizes to VS, the VS at the time of engaging should be a value that can be sustained. Otherwise airspeed will diminish as the aircraft attempts to sustain VS. As airspeed then diminishes to the pre-set minimum it will hold this value and thus prevent a stall.
11 DFC Series Setup Procedure will now move Lateral Setup The lateral setup consists of setting activity, torque, serial baud rate, and magnetometer calibration and various configuration parameters. To enter the setup mode, press and hold the [MODE] button for two or more seconds, until the first setup screen appears. This screen shows current values for the activity and torque of the aileron servo, with an underline under the present setting of activity.
12 its setting and set the baud rate of the autopilot to the same value. The autopilot will recognize NMEA-0183 protocol, Garmin protocol, or Apollo GX50/GX60 protocol (moving map output). Once the desired baud rate has been selected, again press and quickly release the encoder knob to confirm and enter the selected baud rate into storage. The unit will now show the next screen: MICROACTIVITY 0 This setting is to be left at zero unless advised by the factory.
13 internal magnetic disturbances within the aircraft, and should be performed once the autopilot is installed in the panel of the aircraft. It may need to be repeated if the autopilot is moved within the panel, or if new equipment is installed nearby. In order to skip this step, press and quickly release the encoder knob while N is selected.
14 has been averaged for twenty seconds, the process is complete and the screen will show: CALIBRATION DONE PRESS ENTER At this time, press and quickly release the encoder knob to confirm the calibration and enter the resulting data into permanent memory.
15 will now move to the torque setting: VRT ACTIVITY 4 VRT TORQUE 200 In a manner similar to activity, use the encoder knob to select the desired value of pitch servo torque. This value should be between 75 and 250. A default value is set at the factory but may need to be modified to suit a particular aircraft. The value chosen should be sufficient to fly the aircraft, but not so much that it is difficult to override the autopilot if necessary.
16 TruTrak Flight Systems, Inc. (5-06) Printed in U.S.A.
