Cessna 150L N18677 accident near Goble, Oregon

Probable cause

The flight instructor's decision to continue flight into the area of reduced visibility and the pilots’ subsequent failure to maintain clearance from the hilly terrain while operating in an area of low ceilings, rain, and fog.

NTSB analysis

The dual instructional flight was operated in an area where light rain, fog, and overcast ceilings were present. As the flight proceeded, it entered a hilly area with steady rain, low ceilings, and dense ground fog that extended to above tree height. While maneuvering in that area, the pilots did not maintain sufficient altitude, and the airplane impacted a tree that was likely hard to see because of the reduced visibility. Postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR12FA136 for the full record.