Pilot Debrief

CESSNA 150L near Russellville, OH — 2016-08-05

Final reportCEN16LA306
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Date
2016-08-05
Location
Russellville, OH, USA
Airport
KGEO
Aircraft
CESSNA 150L
Registration
N10770
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Descent

Probable cause

A partial loss of engine power due to a fatigue crack of the No. 2 cylinder cooling fin, which resulted in failure of the No. 2 cylinder.

NTSB narrative

As the private pilot was descending the airplane for landing, he heard a loud "bang," and the engine subsequently began running rough. Unable to maintain altitude, the pilot conducted a forced landing to a soybean field, during which the airplane impacted a ditch and nosed over. Examination of the engine revealed that the No. 2 cylinder was completely separated between the flange and the head. Examination of the cylinder revealed a fatigue crack that initiated at a cooling fin valley on the exterior surface. The fatigue crack grew around 40% of the circumference of the cylinder, and overstress led to the eventual cylinder fracture. A metallographic cross-section of the cylinder revealed corrosion pits under the paint and primer. The alloy is not necessarily susceptible to pitting, but crevice corrosion near an unpainted area or exposure to salt environments can lead to similar corrosion features.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Performing maintenance checks on the engine before the flight.

NTSB coding

Evidence available

  • Photos
  • 4 docket documents
View NTSB final reportView NTSB docket

Docket documents4

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