Garmin G5 – the versatile replacement for VAC driven instruments. Below a picture of a Piper PA28 were we replaced the VAC driven directional gyro for a G5 HSI with a remote magnetometer and autopilot interface. We also installed a Garmin GNC255A COM/NAV. G5 HSI system (hardware only) is about $3100 compared to a CDI electro mechanical NAV indicator USD2300. The G5 has it’s limitations – it will not (fully) interface with 70’s technology so the attitude indicator had to stay – required by the old Century IIB autopilot.