BAXLEY, GA, USA
N7793U
CESSNA T210R
ACCORDING TO THE PILOT AND MECHANIC, THE ENGINE QUIT DURING THE FIRST HOUR OF THE INSTALLATION BREAK-IN PROCEDURE, AND A FORCED LANDING WAS ACCOMPLISHED ON A COUNTY ROAD. THE INITIAL EXAMINATION OF THE ENGINE REVEALED A HOLE IN THE TOP OF THE ENGINE CASE. THE SUBSEQUENT TEARDOWN EXAMINATION DISCLOSED THAT THE CRANKSHAFT INTERNAL OIL TUBE AT THE NUMBER TWO JOURNAL WAS DAMAGED, AND RESTRICTED THE NORMAL FLOW OF ENGINE OIL TO THE CONNECTING ROD BEARING. DURING THE CRANKSHAFT OVERHAUL GRINDING PROCESS, ALL OIL TUBES ARE REMOVED FROM THE ASSEMBLY. THE ENGINE ASSEMBLY WAS OVERHAULED AT AN APPROVED FAA REPAIR STATION.
On February 23, 1994, at 1055 eastern standard time, a Cessna T210R, N7793U, collided with a utility line while making an emergency landing to Georgia State Highway 341, 10 miles south of Baxley, Georgia. The maintenance test flight operated under 14 CFR Part 91, with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane sustained substantial damage; the pilot and mechanic were not injured. The flight departed Baxley at 1045 hours. On January 20, 1994, the engine from N7793U was overhauled by High Performance Aircraft Engines And Components, Inc., Mena, Arkansas. A maintenance log statement confirmed that the engine was overhauled in accordance with Continental Motors Overhaul Manual. The overhauled engine and break-in instructions were delivered to the owner for installation. On February 21, 1994, the mechanic completed the installation of the engine on the airframe. On January 23, 1994, at 0950, the pilot and mechanic departed Brunswick, Georgia, to began the first flight of the break-in procedure. Upon reaching the cruise altitude, the mechanic recorded the required engine instrument readings. After thirty minutes of cruise flight at a reduced power setting, the throttle was advanced to full power. Moments later, the engine developed a vibration, and the power was again reduced as the pilot established an approach into Baxley. After landing, the mechanic noticed that the oil pressure had dropped to 20 or 25 pounds. The engine was shut down, and the airplane was towed to the hangar. An examination of the engine revealed that the oil pressure line connecting the turbocharger controller was loose. The line was secured, the engine was washed down, and the flight departed Baxley enroute to Brunswick. At 1050, the pilot established a slow climb to his cruise altitude. Approximately five minutes into the flight, the pilot reduced power as the airplane reached its cruise altitude. Seconds after reducing the engine power a vibration was again felt in the airframe; the pilot elected to return to Baxley. Within seconds of the onset of the vibrations the pilot observed a reduction in engine power and a hole in the top of the engine compartment cowling. The pilot selected a touchdown point on Georgia State Highway 341 and attempted a forced landing. After avoiding obvious utility lines during the emergency descent, the pilot did not see the thin utility line which damaged the vertical fin of the airplane. The engine teardown examination disclosed that the oil tube used to feed the number two journal of the crankshaft was bent and restricted. The damaged tube could be observed through the lightning hole forward of the number two cheek. The damaged tube was so restrictive that a 0.019 inch wire was difficult to pass through the opening. The connecting rod bearing broke up and was recovered from the engine crankcase; the number two journal was scored and blue in color. Examination of the other oil tubes was unremarkable (see attached engine examination report). According to the engine overhaul manual, during the crankshaft overhaul and grinding process, all oil tubes are removed from the assembly. A review of the engine maintenance log disclosed that the crankshaft was reworked and ground to an undersized specification.
DAMAGE TO THE CRANKSHAFT INTERNAL OIL TUBE BY OTHER MAINTENANCE PERSONS DURING THE ENGINE OVERHAUL THAT RESULTED IN OIL STARVATION.
Source: NTSB Aviation Accident Database
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