On May 9, 1986, a Schweizer GRUMMAN G-164B (registration N8493K) was involved in an aviation accident near Harrisburg, AR. Investigators recorded the probable cause as: The pilot's failure to maintain sufficient altitude to clear obstacles due to reduced forward visibility caused by wind-shifted chemicals on the windshield and sun glare. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot conducting agricultural spraying lost forward visibility when wind shifted, depositing chemicals on the windshield. Combined with sun glare, the pilot failed to maintain sufficient altitude to clear field levees.
What happened
The pilot was engaged in an agricultural application flight, spraying a field with the herbicides propanil and penoxalin. During the operation, environmental conditions changed abruptly when the wind shifted from the southeast to the northeast. This shift caused the applied chemicals to drift back toward the cockpit, coating the windshield and significantly reducing the pilot's forward visibility.
Compounding the visual obstruction was intense sun glare. The combination of the chemical film on the glass and the bright sunlight impaired the pilot's ability to see the terrain clearly. As a result, the pilot did not maintain sufficient altitude to clear the levees surrounding the field, leading to contact with the ground.
Probable cause
The pilot's failure to maintain sufficient altitude to clear obstacles due to reduced forward visibility caused by wind-shifted chemicals on the windshield and sun glare.
What happened in the 9 May 1986 Schweizer GRUMMAN G-164B accident near Harrisburg, AR?
A pilot conducting agricultural spraying lost forward visibility when wind shifted, depositing chemicals on the windshield. Combined with sun glare, the pilot failed to maintain sufficient altitude to clear field levees.
What aircraft was involved and where did it happen?
The accident on 9 May 1986 involved a Schweizer GRUMMAN G-164B, registration N8493K, at Harrisburg, AR.
What was the probable cause of the accident?
The pilot's failure to maintain sufficient altitude to clear obstacles due to reduced forward visibility caused by wind-shifted chemicals on the windshield and sun glare.
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