MIA97LA066

The engine lost partial power and engine oil leaked out, covering the windshield. About 3 miles from the airport the engine quit completely. While making a forced landing downwind, the aircraft overran the runway, collided with 2 fences, and nosed over. Postcrash examination of the engine showed the No. 3 connecting rod had disconnected from the crankshaft. One of the No. 3 connecting rod nuts was found in the oil pan with no thread damage and the threaded portion of the respective rod bolt for this nut was found protruding through the engine case with no thread damage. All other engine damage was consistent with secondary damage following connecting rod separation. The engine had accumulated 47 flight hours since major overhaul, at which time the connecting rod bolts were replaced.

On January 19, 1997, about 1042 eastern standard time, a Cessna 172P, N136FR, registered to Keep Em Flying USA, Inc., overran the runway while making a forced landing following loss of engine power at Fort Lauderdale Executive Airport, Fort Lauderdale, Florida, while on a Title 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft received substantial damage and the private-rated pilot and one passenger received minor injuries. The flight originated from Hollywood, Florida, the same day, about 1010.

The pilot stated that after takeoff from North Perry Airport, Hollywood, Florida, he flew north along the coast and the then flew inland north of Pompano Beach, Florida. When about 10 miles northwest of Fort Lauderdale Executive Airport, the engine made a loud noise and lost power. Oil leaked from the engine onto the windshield. He turned toward Fort Lauderdale Executive Airport, and about 2 to 3 miles from the airport the engine quit completely. While making a downwind forced landing on runway 13, at Fort Lauderdale Executive Airport, the aircraft overran the runway, collided with two fences, and nosed over.

Post crash teardown examination of the engine was conducted by NTSB. The examination showed there was a hole in the top of the engine crankcase forward of the No. 2 cylinder and adjacent to the No. 1 cylinder. There was a hole in the bottom of the crankcase, over the oil pan, in the area of the No. 3 cylinder. The No. 3 connecting rod was disconnected from the crankshaft. The threaded portion of one rod bolt from this rod was found imbedding in the crankcase and protruding out of the crankcase at the hole in the top of the case. The remainder of the bolt and nut, the other bolt and nut, and a piece of the connecting rod were found in the oil pan. The No. 1 and No. 2 connecting rod bolts had some bending damage. One bolt on the No. 2 connecting rod had separated. No other evidence of mechanical failure or malfunction was found in the engine.

Examination of the connecting rods and bolts was conducted at the NTSB Materials Laboratory in Washington, D.C. The rod bolt from the No. 3 connecting rod, which was embedded in the top of the engine case, had no damage to the threads. The nut for this bolt, which was found in the oil pan, did not have any thread damage. The failure points on the bolt were typical of overstress separation. The other No. 3 connecting rod bolt had separated in overstress at multiple locations and the nut had separated due to overstress. The portion of No. 3 connecting rod which had separated had features typical of overstress separation. The separated bolt from the No. 2 cylinder had separated due to bending overstress. The bending in the bolts for the No. 1 and 2 cylinders was consistent with secondary damage after separation of the No. 3 connecting rod.

Logbook records showed the engine had received a major overhaul on October 23, 1996, at aircraft total 9752.5. New connecting rod bolts and nuts were installed at this time. At the time of the accident the engine had accumulated 47 flight hours since the major overhaul. See attached logbook records and engine overhaul records.