What happened
On August 6, 2017, at approximately 13:45 local time, a Cessna A188B, registration HK647, was performing low-altitude agricultural spraying operations over a rice field in the Vereda San Vicente, near Trinidad, Casanare. The aircraft, operated by Servicio Aéreo del Oriente - SAO S.A.S., was executing its third pass over the field when its main landing gear struck high-voltage electrical power lines.
The impact caused the aircraft to lose control and pitch downward, leading to a subsequent impact with the terrain. The aircraft sustained significant structural damage, including the separation of the engine from its mount and damage to the landing gear. The pilot, who was the sole occupant, sustained minor injuries but was able to exit the aircraft on his own. There was no post-impact fire, though the collision caused damage to the electrical infrastructure, affecting lines with voltages of approximately 45kV and 132kV.
The investigation
The GRIAA investigation confirmed that the aircraft was airworthy and that all maintenance requirements and airworthiness directives were up to date. The engine and propeller were functioning normally at the time of the accident. Meteorological conditions were visual (VMC) with daylight, and calculations showed that the sun's position did not cause any glare that could have obscured the pilot's vision.
The investigation focused on the pilot's operational procedures and the organization's risk management. While the pilot was highly experienced and held a valid commercial license, investigators identified a lack of adequate flight planning regarding the identification of obstacles within the work area. Furthermore, the investigation examined the company's safety management systems, specifically looking at how hazards were identified and mitigated during agricultural operations.
Findings
- The primary cause of the accident was the collision of the aircraft with electrical power lines during low-altitude flight.
- The pilot's actions were influenced by overconfidence and inattention during the low-altitude maneuvers, which led to the failure to detect the obstacle.
- A contributing factor was the insufficient risk management by the operator during the planning and execution phases of the agricultural spraying flights.
- The pilot failed to adequately plan the operation to account for the latent hazard posed by the power lines.
Safety action
Following the investigation, several recommendations were issued to the operator, including the requirement to update the General Operations Manual to include mandatory field studies and risk assessments of work areas prior to flight. The operator was also advised to conduct a comprehensive risk landscape survey of all operational lots and to improve hazard identification processes through its safety committee.