Accident Details
During a night aerial application flight, a multiengine airplane impacted trees bordering a bayou/swamp area. The aircraft was operated by a single pilot accompanied by a crew member responsible for operating the spraying equipment. Company personnel stated that the crew member never flew the airplane. Two other pilots who were also flying observed patchy fog forming along the ground and around the wooded bayou areas and subsequently returned to the airport.
Weather Conditions
Marginal VFR weather with mist and thunderstorms was forecast for the area. AIRMET Sierra was valid, indicating ceilings below 1,000 feet AGL and visibility below 3 statute miles with precipitation and mist. Area weather stations reported a temperature/dewpoint spread of one degree or less. Radiosonde data showed a temperature/dewpoint spread of 4 degrees or less from the surface to 5,407 feet MSL. Terminal forecasts indicated winds of 5 knots or less. The average relative humidity was 90%, and precipitable water was 139%. Local authorities noted that fog often forms like a cloud out of the woods and spreads at tree height during night hours.
Pilot Information
The pilot's total flight time in the PA-23 airplane was 75 hours, with 9.0 hours logged in the previous 3 years.