What happened
The aircraft experienced a loss of altitude during the initial climb phase following takeoff. The pilot estimated that the aircraft reached an altitude of 60 feet above ground level before settling back toward the surface. During this sequence, the pilot recognized that the aircraft was descending and observed a corresponding decrease in airspeed.
In response to the deteriorating flight path, the pilot decided to retain the agricultural payload for as long as possible before initiating a dump. The pilot reported dumping the load at an altitude of 20 feet above the anticipated point of ground impact. The aircraft ultimately made contact with the ground after this maneuver.
The investigation
An investigation into the flight parameters determined that the density altitude was calculated to be 4,700 feet, despite the airport elevation being only 3,800 feet. This significant difference indicates reduced engine performance and aerodynamic efficiency due to atmospheric conditions.
The pilot identified the specific aerodynamic phenomenon responsible for the loss of climb capability as the "region of reverse command." This condition occurs when total drag increases as airspeed decreases, requiring more power to maintain level flight or climb. The investigation confirmed that the aircraft was carrying a substantial payload consisting of 200 gallons of 2,4-D and Roundup herbicides, in addition to 55 gallons of aviation fuel.
Findings
The primary factor contributing to the accident was the pilot's entry into the region of reverse command during takeoff. The combination of high density altitude and a heavy agricultural load resulted in insufficient power available to maintain altitude as airspeed dissipated. The pilot acknowledged this error in his post-accident report, citing the aerodynamic limitations encountered at low speeds with high drag.