As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
COMPRESSION CHECK REVEALED ZERO COMPRESSION IN THE NR 3 CYLINDER. INVESTIGATION FOUND A HOLE BURNED THROUGH THE HEAD OF THE EXHAUST VALVE. THE FAILURE SEEMED UNUSUAL BECAUSE THERE WERE MULTIPLE CRACKS IN THE HEAD OF THE VALVE IN A CIRCUMFERENTIAL ORIENTATION AROUND THE STEM BUT THE EDGE OF THE VALVE AND THE SEATING AREA APPEARED IN REASONABLY GOOD CONDITION FOR THE TIME IN SERVICE. (AL01200404049)