What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) The aircraft is owned and operated by tucson aeroservice center inc. and maintained by tucson aeroservice center inc. FAA certificated repair station YXUR055J (yxur) located in marana AZ. Investigation revealed the #3 cylinder exhaust rocker arm had disconnected from the cylinder causing the engine to lose power resulting in the forced landing and substantial damage to the aircraft. According to records, the #1 and #3 cylinders were removed to repair oil leaking from the cylinder hold down studs on 9/14/2007, 13.4 hours prior to the accident. The personnel at the repair station had not removed the rocker covers or the rocker arms from the cylinders. The procedures used to remove and replace the engine cylinders is contrary to avco Lycoming 76 series overhaul manual section 5 paragraph 5-8 which requires the removal of the rocker box cover and rocker arms and the requirement for setting the valve clearance per paragraph 5-90. Apparently the rocker arm was in the process of backing off the cylinder and had the proper procedure been used to install the cylinder the discrepancy would have been noted and corrected, preventing the accident.
As the FAA filed it
(-23) THE AIRCRAFT IS OWNED AND OPERATED BY TUCSON AEROSERVICE CENTER INC. AND MAINTAINED BY TUCSON AEROSERVICE CENTER INC. FAA CERTIFICATED REPAIR STATION YXUR055J (YXUR) LOCATED IN MARANA AZ. INVESTIGATION REVEALED THE #3 CYLINDER EXHAUST ROCKER ARM HAD DISCONNECTED FROM THE CYLINDER CAUSING THE ENGINE TO LOSE POWER RESULTING IN THE FORCED LANDING AND SUBSTANTIAL DAMAGE TO THE AIRCRAFT. ACCORDING TO RECORDS, THE #1 AND #3 CYLINDERS WERE REMOVED TO REPAIR OIL LEAKING FROM THE CYLINDER HOLD DOWN STUDS ON 9/14/2007, 13.4 HOURS PRIOR TO THE ACCIDENT. THE PERSONNEL AT THE REPAIR STATION HAD NOT REMOVED THE ROCKER COVERS OR THE ROCKER ARMS FROM THE CYLINDERS. THE PROCEDURES USED TO REMOVE AND REPLACE THE ENGINE CYLINDERS IS CONTRARY TO AVCO LYCOMING 76 SERIES OVERHAUL MANUAL SECTION 5 PARAGRAPH 5-8 WHICH REQUIRES THE REMOVAL OF THE ROCKER BOX COVER AND ROCKER ARMS AND THE REQUIREMENT FOR SETTING THE VALVE CLEARANCE PER PARAGRAPH 5-90. APPARENTLY THE ROCKER ARM WAS IN THE PROCESS OF BACKING OFF THE CYLINDER AND HAD THE PROPER PROCEDURE BEEN USED TO INSTALL THE CYLINDER THE DISCREPANCY WOULD HAVE BEEN NOTED AND CORRECTED, PREVENTING THE ACCIDENT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.