iFly can steer an autopilot. It sends your position, track and the active flight plan as NMEA sentences over a serial connection, and the autopilot flies the route. This page covers the wired setup used by iFly GPS portables and the Aviation Tablet docking station. For Bluetooth, see Send NMEA data over Bluetooth.

Six-minute overview

Quick Tip · Autopilot in iFly EFB · 5:36  ·  Open on YouTube

Three ways to connect

Step 1 · Wire it

NMEA travels over an RS-232 serial link. Three pins matter: TX (transmit), RX (receive) and GND (ground). iFly's TX goes to the autopilot's RX; connect ground as well if the autopilot manual calls for it.

• iFly GPS portables use a USB-to-serial cable with a male DB9 plug. Buy one with an FTDI chipset; the cheaper Prolific-chipset cables cause intermittent dropouts. The cable from our store is FTDI.
• Aviation Tablet uses the female serial connector on the docking station. The dock must be hard-wired to ship's power through its round plug.
• The optional DB9 breakout board plugs onto the cable and gives you screw terminals, so a single-wire autopilot, fuel computer or other NMEA device connects to pin 3 without soldering.

Step 2 · Turn on NMEA output in iFly

1. Connect the cable (or dock the tablet) and open iFly.
2. Go to Menu › Setup › NMEA Output.
   • On an iFly GPS portable, if this option is missing the serial cable is not being detected. Try another cable before suspecting the USB port.
   • On the Aviation Tablet, check Send to Com Port.
3. Choose Custom and set the baud rate and the sentences your autopilot expects. Both are in the autopilot's installation manual; common baud rates are 4800 and 9600.

Step 3 · Test on the ground

iFly only transmits when it has a position, so test in simulation: Menu › Start Simulation Mode › Show Simulation Controls, load any flight plan, and use the controls to add speed and a climb. Then check Menu › About › Connected Devices: an NMEA Output Controller entry appears and its sentence count climbs. The autopilot should show it is receiving a course. On a 740b, allow about a minute after connecting; the unit listens for an input device before switching to output mode.

NMEA sentences iFly can send

Troubleshooting

• NMEA Output is missing from Setup (portables): the cable is not detected. Try a different FTDI cable. If a known-good cable is not detected either, the USB port has failed; ports on iFly GPS units are not repairable.
• Connected Devices says "sending to none": iFly is not transmitting. Re-check Step 2, then restart the unit.
• Sentence count stays at zero: no position. Get a GPS lock or use Simulation Mode.
• Autopilot receives nothing: TX and RX are swapped, or the baud rate does not match. Swap the wires at the breakout board, then check the baud rate.
• Works, then drops out: almost always the cable. Replace a Prolific-chipset cable with an FTDI one.
• iFly 520 with a serial ADS-B receiver: the 520 has one serial path, so it cannot drive an autopilot and receive serial ADS-B at the same time. A 720 or 740 can, by taking ADS-B over Wi-Fi.