RIALTO, CA, USA
N34021
Cessna 177B
The accident flight was the first flight following an oil change. While in cruise flight about 38 minutes after takeoff, the engine began to run roughly and the oil pressure dropped to zero. The engine then completely lost power and the pilot attempted to land at the airport. He touched down short of the runway and collided with a fence. During the postaccident examination, oil was evident on the firewall, rear engine case area, and in the area of the oil pressure screen housing, streaming aft on the underside of the aircraft and on the forward edge of both landing gear struts. The screws that attach the oil pressure screen were observed to be improperly secured; there was no discernible torque required to loosen the screws. The oil pressure screen had been removed during the oil change. The improperly torqued oil screen housing bolts resulted in the loss of oil, and the number 2 cylinder connecting rod bearing failure and overheating of the connecting rod. The connecting rod released from the crankshaft journal and punctured the upper left crankcase, damaging the adjacent components.
On January 7, 2000, at 1753 hours Pacific standard time, a Cessna 177B, N34021, experienced a loss of engine power during cruise flight and force landed at the Rialto, California, airport. The airplane, owned and operated by the pilot, sustained substantial damage. The private pilot was not injured. The personal cross-country flight, conducted under the provisions of 14 CFR Part 91, originated at the Whiteman Airport, Pacoima, California, at 1715, and was en route to Redlands. Night visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that this was the first flight following an oil change. While in cruise flight, the engine began to run roughly and the oil pressure dropped to zero. The engine then lost power. The pilot attempted to land at the airport, but touched down short of runway 06 and collided with a fence. The airplane was examined on January 12, 2000. The belly of the airplane was stained with large streaks of oil. The engine cowling was removed and oil was evident in the area of the oil pressure screen housing, rear case, streaming aft on the underside of the aircraft and on the forward edge of both landing gear struts. The oil lines were secure at their respective fittings and neither line displayed dripping or leaking oil. The oil tank was found empty. There was no discernible torque required to loosen the screws that attached the oil pressure screen/vernatherm housing. The Lycoming maintenance manual indicated that the torque required for the oil pressure screen housing screws was 96 inch-pounds. The lock washers did not exhibit a "crushed" appearance. Oil was pooled underneath the screen area, streaming down to the belly of the airplane. During disassembly, the suction screen plug was found to be safety wired; however, it was found "finger loose." The Lycoming torquing procedures require that the plug be "finger tight, then tightened an additional 135 degrees." The plug was removed from the oil sump. The thickness of the annular gasket was measured approximately 0.032 inches. According to Lycoming, nominal thickness after proper torque application should be approximately 0.075 inches. Further, it is a "one-time-use" gasket, and should be discarded after each removal and replaced with a new one. A copy of the invoice for the oil change from the day of the accident is appended to this file. The statement on the invoice reads, "Changed oil, and take off oil filter to clean, check the gasket and replaced lock-washers." A hole slightly less than the diameter of a quarter was found between the pushrod tubes in the left half of the crankcase at the number 2 cylinder location. The area surrounding the hole in the crankcase did not exhibit the presence of a large quantity of oil or oil residue. The inside of the cowling covering the number 2 cylinder displayed minimal oil spray. The rocker box covers were removed and each displayed minimal oil coverage. The Nos. 3 and 4 cylinders were removed. They were clean and displayed normal combustion deposits. The Nos. 1 and 2 cylinders were removed; the cylinder barrels were distorted. The spark plugs were removed; they exhibited normal color and wear patterns consistent with the Champion Check-A-Plug chart. The engine could not be rotated. The aircraft maintenance logbooks were reviewed. According to the logbooks, the engine had been overhauled on March 26, 1999, approximately 83 hours prior to the accident. The airplane had undergone an annual inspection on June 1, 1999, about 67 hours before the accident. The last entry in the logbook, dated August 16, 1999, was for an oil change. There was no entry recorded in the logbooks for the oil change on the day of the accident.
The failure of the maintenance personnel to follow the manufacturer's procedures and directives regarding the proper torquing of the screws securing the oil pressure screen housing, which resulted in the loss of lubricating oil, and the subsequent seizure of the engine.
Source: NTSB Aviation Accident Database
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