Schematic, that's why I asked if he had an autopilot. I've seen those raise havoc with compasses that are to close. Also, seen VHF radios play havoc with autopilots.
Magnetic interference can come from a number of sources and is most likely the reason if no special equipment is fitted.<br /><br />Especially objects containing magnets (speakers etc.) can cause this, but most metal items does it to some extent. Even wristwatches.
