As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT WAS FLYING DURING A SEISMIC JOB. ENGINE LOST POWER AND ENGINE WAS RUNNING ROUGH. EMERGENCY LANDING TOOK PLACE. MAINTENANCE INVESTIGATED AND FOUND NR 1 CYLINDER DEFECTIVE. UPON FURTHER INVESTIGATION INTAKE VALVE STUCK OPEN AND CONTACTED PISTON. CYLINDER AND PISTON WERE REPLACED AND AIRCRAFT WAS PUT BACK IN SERVICE. (TC NR 20070503008)