2017 Piper PA-25-260 agricultural spraying accident in Ambalema, Colombia (HK585)

Overview and Operation Details On 23 February 2017, a Piper PA-25-260 with registration HK585, operated by Sanidad Vegetal Cruz Verde S.A.S., was conducting agricultural spraying operations in Ambalema, Tolima, Colombia. The aircraft had previously completed fumigation work at three lots in Hacienda El Triunfo near the Cerritos auxiliary base. At 09:00 local time (14:00 UTC), HK585 departed Cerritos for the Hacienda Pajonales airstrip to continue spraying. ## Accident Sequence During the seventh pass over lot 326 at Hacienda Pajonales, the pilot reported an uncommanded leftward movement to the main base but decided to continue the operation. On the eighth pass, after leaving the area where solid fertilizer was applied, the left wing suddenly banked sharply to the left. The aircraft lost control and impacted the terrain at a high angle and high speed. ## Damage and Injuries The aircraft came to rest at coordinates N04°44’50.6’’ W074°50’28.1’’. The wreckage was concentrated in one area, except for the propeller, which detached completely. The engine separated from the firewall, the left landing gear fractured, and the cockpit, left wing, and horizontal and vertical stabilizers were destroyed. The impact occurred on a heading of 70°, with a final heading of 140°. No pre- or post-impact fire occurred. The sole occupant, a 25-year-old pilot, was extracted in serious condition by hacienda workers and transported to a hospital in Ibagué. The pilot remained in an induced coma for 10 days due to the severity of the injuries. ## Investigation Findings The investigation determined the probable cause to be a pilot-induced loss of lift during the 90-270 (reversal) maneuver used in agricultural spraying to position the aircraft over the target area. A contributing factor was the lack of clarity and standardization in the operator's manuals regarding the Piper PA-25's stall characteristics and speeds, the 90-270 maneuver, and low-altitude stall prevention and recovery. ## Aircraft and Environmental Factors The aircraft, manufactured in 1970, had 6,620 total flight hours and was compliant with all maintenance and airworthiness requirements. The Lycoming O-540-G1A5 engine had 13,583:30 total hours. Meteorological conditions at the accident site were suitable for visual flight rules, with wind variations between 5 and 6 knots, and were not a factor in the accident. The aircraft was not equipped with a flight data recorder or cockpit voice recorder, as these were not required for this type of aircraft under Colombian aviation regulations.