On April 25, 1988, a Maule M5-210C (registration N312X) was involved in an aviation accident near Bend, OR. Investigators recorded the probable cause as: The pilot's failure to maintain visual reference due to inadequate vision correction and poor weather conditions, resulting in a controlled flight into terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot flew into known poor weather conditions without corrective lenses, resulting in a controlled flight into terrain during low visibility snow.
What happened
The pilot filed a visual flight rules (VFR) flight plan despite being explicitly advised that VFR conditions were not recommended. A witness observed the aircraft on course for its destination at a low altitude over a highway, estimating the ceiling to be approximately 100 feet with poor visibility due to moderate snowfall. The aircraft was then seen executing a sharp left turn before impacting rising terrain.
Findings
The investigation revealed that the pilot was required to wear corrective lenses for vision correction, as their uncorrected vision was rated at 20/200. At the time of the accident, these corrective lenses were not being worn. This lack of visual correction, combined with flying into deteriorating weather conditions contrary to safety advice, contributed significantly to the loss of situational awareness and the subsequent collision with terrain.
Safety message
Pilots must strictly adhere to weather advisories and ensure all required personal equipment, such as corrective lenses, is available and used during flight operations.
Probable cause
The pilot's failure to maintain visual reference due to inadequate vision correction and poor weather conditions, resulting in a controlled flight into terrain.