Robinson R44 II crash near Van Nuys, California, United States

An improper repair of the right magneto's tachometer and governor signal wire, which failed during cruise flight and initiated a simultaneous malfunction of both the engine tachometer and governor control system, which resulted in erroneous and contradictory information between the engine tachometer and main rotor tachometer that led the pilot to perform a forced landing. Contributing to the accident was the lack of guidance on how to address the simultaneous failure or malfunction of both the engine tachometer and governor control system.