FTW01LA009

During climb to cruise, approximately 1,100 feet agl, the pilot heard a 'loud sound' from the engine, followed by a 'hard vibration.' The pilot turned toward the airport and then the engine lost power. The pilot initiated a forced landing to a field near the airport. The airplane struck a tree and impacted terrain. A teardown examination of the engine revealed that the crankshaft was fractured at the lead bushing hole in the number 2 cheek counterweight housing. The crankshaft 'bump' surface at the fractured leading end exhibited polishing from the counterweight hitting the surface. The polishing could only occur if the rear pin had escaped and the counterweight stood up, hitting the camshaft and crankcase as it trailed through the engine. The counterweight housing had fractured due to overload.

On October 12, 2000, at 1830 central daylight time, a Bellanca BL17-30 single-engine airplane, N4882V, was substantially damaged during a forced landing following a loss of engine power near Waller, Texas. The private pilot and passenger received minor injuries. The airplane was owned and operated by the pilot and passenger. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulation Part 91 personal flight. The local flight originated from Skydive Airport near Houston, Texas at 1825.

According to a telephone interview with the pilot conducted by an NTSB investigator and the pilot's statement, after takeoff, approximately 1,100 feet agl, a "loud sound came from the engine, followed by a hard vibration." With the engine still running, the pilot "turned toward the airport and then the engine quit." The pilot initiated a forced landing to a field near the airport. The left main gear struck a tree, pulling the aircraft to the left. The airplane impacted the ground and came to rest upright.

According to maintenance records, on October 22, 1999, the Continental IO-520-D engine, serial number 158848-8-D, had a top overhaul completed at 2,317.4 hours aircraft total time. All cylinders, rods, rod bolts, rod nuts, and rod bearings were removed and replaced. At the time of the accident, the aircraft had 2,359.04 hours total time, and the engine had 702.87 hours total time since major overhaul and 41.64 hours total time since top overhaul.

An FAA inspector, who responded to the accident site, stated that the connecting rod on the #2 cylinder was broken. The wings, landing gear, and engine firewall were structurally damaged.

On February 9, 2001, NTSB representatives, an FAA inspector, and a Teledyne Continental Motors (TCM) representative witnessed an engine teardown that was conducted at Air Salvage of Dallas, near Lancaster, Texas. The teardown examination revealed that the crankshaft was fractured at the lead bushing hole in the number 2 cheek counterweight housing, and the corresponding counterweight was missing. A portion of the crankshaft, two counterweight pins, bushings, one plate, and remnants of two snap rings were retained for further metallurgical examination.

The crankshaft and counterweight components were examined at the TCM facility on March 21, 2001, under NTSB supervision. According to TCM, "the crankshaft 'bump' surface at the fractured leading end exhibited polishing from the counterweight hitting the surface. The polishing could only occur if the rear pin had escaped and the counterweight stood up, hitting the camshaft and crankcase as it trailed through [the] engine." The crankshaft counterweight housing had fractured due to overload. The counterweight pins were measured and were found to be within TCM specifications.