Accident Overview
A Monroe County Mosquito Control operation aircraft conducting low-altitude spraying struck mangrove trees and crashed on Water Key near Summerland Key, Florida. The flight departed at approximately 1740 EDT. When it failed to return, a search was initiated, and the wreckage was located at about 0245. Evidence indicated the left wing struck 40-foot-high mangrove trees as the pilots were making a procedure turn to begin another spray run. The accident is estimated to have occurred at around 2030 EDT. Sunset on the day of the accident was at 1952 EDT.
Weather Conditions
Weather reported at Key West, about 22 miles southwest, at 1750 included scattered clouds at 1,500 feet, visibility of 10 miles, and wind from 330° at 10 knots. Approximately 85 miles north-northeast, the wind was from 100° at 11 knots. The light condition at dusk was noted as a contributing factor.
Investigation Findings
No preimpact failure or malfunction of the aircraft or engines was discovered. No known witnesses were identified. Both pilots were killed.
Probable Cause
The official probable cause was the failure of the pilot-in-command to assure proper altitude and clearance was maintained above the terrain and trees. The trees and light condition at dusk were contributing factors.