On November 11, 1996, about 1105 hours mountain standard time, a Cessna 152, N714VX, operated by Sunbird Flight Services, Chandler, Arizona, experienced a total loss of engine power and collided with terrain during initial climb from runway 19 at the Valle Airport, near Williams, Arizona. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight. The airplane was destroyed and the private pilot was seriously injured. The flight was originating at the time of the accident. According to the Coconino County Sheriff's Department, a witness reported observing the airplane following its takeoff. The witness indicated that the airplane appeared to stall, flip upside down, and then collide with trees. The pilot reported that when he first started the engine no indication of engine oil pressure was observed. He shut down the engine and purchased 1 quart of oil. No abnormal indications were observed during the subsequent ground checkout or takeoff roll. During the initial climb, the oil pressure indicator dropped to 0 pounds, and the temperature indicator remained in the normal operating range. There was no indication of engine roughness, but power was lost. The pilot further reported that he checked the magnetos and fuel selector, and he pushed the mixture control in, but the engine continued to lose power. The airplane stalled, collided with trees, and came to rest in an inverted attitude. The airport's elevation is 6,002 feet mean sea level. The computed density altitude was about 7,300 feet. While under the supervision and direction of the Federal Aviation Administration (FAA), the airplane was subsequently examined by a representative from Lycoming Engines. According to the FAA, during the teardown examination the oil pump's drive shaft was found broken. A foreign object was observed wedged between the teeth of the pump's driving and driven gears. The crankshaft engagement end of the oil pump drive shaft was found sheared off. The examination of the crankshaft assembly revealed signatures consistent with heat distress in the number 2 main journal area. The Lycoming representative verbally reported that the visual examination of the foreign object revealed it was metal and had threads. The object resembled a small bolt or screw. No screw or bolt of the type found was used by Lycoming in the engine's manufacture. According to the FAA, during the examinations of the engine and airframe no other findings were made which would have precipitated the loss of engine power or flight control.