Aviation Accident Summaries

Aviation Accident Summary SEA98LA166

MISSOULA, MT, USA

Aircraft #1

N8512X

Cessna 175

Analysis

While in cruise flight, the pilot smelled smoke and noticed a loss of oil pressure. He therefore found an open field in which he could make an emergency landing. After arriving over the field, the engine stopped running and the pilot made a forced landing. During the landing roll, the aircraft's nose gear was torn off when it hit a small pine tree. After the gear was torn off, the aircraft nosed over. A post-accident inspection of the engine revealed that the number three connecting rod had failed and passed through the crankcase. It was also noted that the oil filler tube was missing, and no oil was found in the crankcase.

Factual Information

On August 15, 1998, approximately 1620 mountain daylight time, a Cessna 175, N8512X, nosed over during a power-off forced landing about 15 miles southwest of Missoula, Montana. The private pilot and his passenger were not injured, but the aircraft, which was owned and operated by Hinkle Aviation, of Caldwell, Idaho, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which departed Kalispell, Montana, about 50 minutes prior to the accident, was being operated in visual meteorological conditions. No flight plan had been filed, and there was no report of an ELT activation. According to the pilot, while at cruise, smoke started accumulating in the cabin, so he started checking for abnormal instrument indications. Soon thereafter, he noticed that the oil pressure had dropped to zero. He then reversed course in order to return to an open field he had flown over a few minutes earlier. As he arrived over the field, the engine stopped running, and he attempted a forced landing. His touchdown was successful, but as the aircraft neared the edge of the field, the nose gear hit a small pine tree. When the gear hit the tree, the entire nose gear assembly was torn from the fuselage and the aircraft nosed over. A post accident inspection of the engine revealed that the oil filler tube had separated from the engine and was not found at the accident site. Almost all of the engine oil had drained from the crankcase, and the number three connecting rod had failed and come through the side of the case.

Probable Cause and Findings

A complete loss of crankcase oil due to a missing oil filler tube followed by the failure of a connecting rod. Factors include encountering a small pine tree during the landing roll.

 

Source: NTSB Aviation Accident Database

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