You are not expected to be a Garmin systems engineer for this exam. You are expected to know the layout, what each screen shows, where the engine indications live, and — the part the examiner really wants — how the autopilot behaves and which failures knock it out. Keep it at that level and this chapter is straightforward.
The DA-42 NG is built around an integrated avionics suite: a Primary Flight Display (PFD), a Multi-Function Display (MFD), an audio panel, an Attitude and Heading Reference System (AHRS) and an Air Data Computer (ADC), all sharing information. Inside it are dual GPS receivers, dual VOR/ILS receivers, dual VHF communication radios and a transponder — full redundancy in the navigation and communication kit.
The PFD in front of you presents airspeed, attitude, altitude and heading in the familiar tape-and-ball layout. Slip is shown as a trapezoid under the bank pointer, turn rate on the scale above the compass, and short magenta "trend" lines predict where speed and altitude are heading. Crucially, the PFD also carries the crew-alerting messages. If the displays misbehave, pressing DISPLAY BACKUP puts the PFD into a composite "reversionary" mode that keeps attitude and alerting alive.
The MFD carries the engine instruments, the moving map, terrain, traffic and the flight plan — and it also holds the autopilot controls. When an engine parameter leaves its normal band, its readout turns yellow for caution and red-and-flashing for warning, so the engine display doubles as an alerting system.
The AHRS blends GPS, rate sensors, air data and magnetic variation to produce attitude and heading; it will align while taxiing but aligns faster if you keep the wings level. The ADC supplies airspeed, altitude, vertical speed and air temperature. Behind both sits an independent standby attitude module showing attitude, altitude, airspeed and slip — powered by its own emergency battery for at least 1.5 hours in a total electrical failure. That is your last-ditch instrument, and it owes nothing to the glass panel.
The autopilot and flight director is the GFC 700 — a three-axis system (pitch, roll and yaw damper) with a flight director. Its lateral and vertical modes are the ones to know:
| Type | Modes |
|---|---|
| Lateral | HDG (heading), NAV/GPS (course tracking), APR (approach), plus a basic roll mode |
| Vertical | ALT (altitude hold), VS (vertical speed), FLC (flight level change / airspeed hold), plus go-around |
| Third axis | YD (yaw damper) |
On the display, green means a mode is active and white means it is armed. The autopilot and manual electric trim will not engage until a preflight self-test completes after power-up, so never rush that test on start.
The autopilot will automatically disconnect on any of: electrical power failure, an internal autopilot fault, an AHRS malfunction, or loss of air-data information. You can disconnect it manually in several ways: the red AP DISC button on the control stick, moving the manual electric trim switch, the AP button on the mode controller, the go-around button on the power lever, pulling the AUTOPILOT breaker, or switching off the AVIONICS MASTER or ELECT. MASTER.