by tdammers » Thu Apr 09, 2020 8:05 am
You're looking for the rightmost levers in the overhead throttle quadrant. From left to right, the levers in that section are throttle (2x), prop pitch (2x), fuel (2x). You also need the fuel pumps running to start the engines.
The autopilot is quite rudimentary, and should be mostly self-explanatory, but here goes.
There are 2 separate controllers: a vertical one, and a lateral one. Each has its own master switch (the bigger "ALT" and "HDG" buttons), which has to be "on" for it to do anything at all, and on top of that, the autopilot master ("AP") also has to be "on". Both controllers have several modes.
For the vertical controller:
- No submode selected means maintain current altitude
- ALT climbs/descends to the altitude selected in the altitude selector dial at a fixed climb/descent rate of 500 fpm
- VS holds the selected vertical speed
- SPD holds the selected airspeed ("speed with pitch" - there is no autothrottle in the DHC6)
- GS arms the ILS glideslope capture; the previously selected vertical mode remains active until the glideslope is captured
Note that, unlike the autopilot systems in a typical airliner, the VS and SPD modes will not disengage and level off when the target altitude is reached, so for example setting target altitude to 7000 ft, target speed to 100 KIAS, and hitting the "SPD" button, will make the aircraft climb through 7000 ft and further.
For the lateral controller:
- No submodes selected means keep wings level
- HDG captures and holds the heading selected with the heading bug
- NAV arms VOR/LOC capture; the previously selected mode remains active until the radial/localizer is captured, after which the NAV mode activates and the previous mode disengages
The fun part about this autopilot is that you can engage/disengage lateral and vertical modes independently, so you can for example enable vertical A/P, but hand-control lateral movements (bank/turn). This is great for sightseeing or flying low in mountainous terrain.
The GPS unit isn't great; it emulates a Garmin 196, with the added twist that, unlike the real thing, the GPS unit can override the NAV1 localizer signal; you can use this feature to make the DHC6 follow a GPS flight plan. Here's how that goes:
- Enter a route into the route manager (Autopilot/Route Manager) and activate it.
- In the GPS menu (Equipment / GPS), select "Leg" mode, and check the "Slave NAV1" box. The NAV1 instrument will now follow the route manager's GPS-based signal rather than the VOR/LOC radial from NAV1.
- Line up, align the heading bug with the runway heading, take off, stabilize, turn autopilot on. Set ALT mode to climb to your cleared altitude, HDG mode to HDG, then arm NAV. If you're not on a suitable heading to intercept the fake NAV1 signal, adjust the heading bug accordingly. Once the autopilot captures the fake radial, the aircraft will keep following the flight plan as long as NAV mode remains active.