Aviation Accident Summaries

Aviation Accident Summary MIA99LA166

ROLLING FORK, MS, USA

Aircraft #1

N9267X

Cessna 182E

Analysis

While climbing through 600 feet after takeoff, a loud bang was heard and a hole appeared in the top of the engine cowling. Oil leaked from the engine and covered the windshield. The engine did not stop running, but did loose power. A forced landing was landing was made in a field and the nose landing gear collapsed during rollout. Post crash examination of the engine showed the number 3 connecting rod had separated from the crankshaft. Examination of the number three connecting rod bolts showed one bolt had failed due to fatigue which emanated from the edge of the bolt in the dowel area. The other bolt separated due to bending overstress. Examination of connecting rod bolts from the numbers 1 and 2 connecting rods showed slight rubbing in the dowel area of the bolts. Breakaway torque on the numbers 1,2,5, and 6 connecting rod bolts showed torque values below the manufacturers requirements.

Factual Information

On June 6, 1999, about 1430 central daylight time, a Cessna 182E, N9267X, registered to Wade and Son, Inc., made a forced landing in a field following loss of engine power near Rolling Fork, Mississippi, while on a Title 14 CFR Part 91 parachute drop 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 four parachutists were not injured. The flight originated from Rolling Fork Airport, a few minutes before the accident. The pilot stated to an FAA inspector that while climbing through 600 feet agl, after takeoff from Wades Airport, the engine banged, and a hole appeared in the top of the engine cowling. Oil covered the windshield and the engine lost power, but the engine did stop running. He made a forced landing in a cotton field, at which time, the nose landing gear collapsed. Examination of the aircraft and engine by an FAA inspector showed the left wing tip was bent, the nose landing gear was collapsed, the firewall was buckled, the engine cowling and engine had a hole in the top. A fire had occurred in the engine compartment causing some damage to wires and hoses. The No. 3 connecting rod was disconnected from the crankshaft, had been ejected from the engine, and was found lying on the nose area of the engine. (See FAA Inspector's Statement.) The engine was removed from the aircraft and shipped to Teledyne Continental Motors, Mobile, Alabama, for teardown examination under NTSB supervision. Teardown examination showed the No. 3 connecting rod separated from the crankshaft when a connecting rod bolt failed. The No. 3 rod journal had mechanical damage. No other evidence of mechanical failure or malfunction within the engine assembly and accessories was found. Breakaway torque on the connecting rod bolts from the remaining 5 cylinders showed that cylinders 1, 2, 5, and 6 had connecting rod bolts torqued below the Teledyne Continental Motors Overhaul Manual requirements. (See Teledyne Continental Motors Report.) Examination of the connecting rod bolts from the Nos. 1, 2, and 3 cylinders was performed by the NTSB Materials Laboratory, Washington, D.C. One connecting rod bolt from the No. 3 cylinder had separated due fatigue crack progression. The fatigue emanated from the edge of the bolt in the dowel area and propagated throughout almost the entire cross section of the bolt. The second bolt from the No. 3 connecting rod had separated due to bending overstress. Examination of one connecting rod bolt from the No. 1 cylinder and one connecting rod bolt from the No. 2 cylinder showed slight rubbing in the dowel area of the bolts. (See Materials Laboratory Factual Report.) Aircraft and engine logbook records showed the engine was last overhauled on September 20, 1995. At the time of the accident the engine had accumulated 5,541 total flight hours and 825 flight hours since overhaul. (See logbook pages.) The pilot was given an NTSB Pilot/Operator Aircraft Accident Report Form 6120.1/2, by an FAA inspector. The completed form was not received by NTSB.

Probable Cause and Findings

Improper torqueing of the connecting rod bolts which resulted in the bolts being loose and rubbing in the dowel area which resulted in fatigue emanation and cracking and separation of the number 3 connecting rod after bolt failure.

 

Source: NTSB Aviation Accident Database

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