As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ENGINE CYLINDER COMPRESSION FOUND TO BE LOW AND GETTING LOWER EACH INSPECTION. HEADS REMOVED AND SENT FOR REPAIR. VALVE TRAIN FOUND DAMAGED, INCLUDING VALVE SEAT RECESSION AND WEAR ON THE VALVE SPRING RETAINER. THIS WEAR IS CONSISTENT WITH AIR IN THE LIFTERS AND IS ADDRESSED BY SI-912-018, OIL PURGE AND FAA AD-2005-01-14. HEADS AND VALVE TRAIN REPLACED.