What happened
On October 12, 2013, a Cessna A188B, registration HK1624, was performing aerial spraying operations over a rice field at the Los Trompillos farm in Villanueva, Casanare. The aircraft, operated by Agrícola de Servicios Aéreos del Meta (ASAM LTDA), had successfully completed six spray passes. During the seventh pass, the pilot noticed the hydraulic spraying system was operating with fluctuations, possibly due to air in the lines.
While flying at an altitude of approximately two meters, the pilot initiated a left turn to interrupt the pass and inspect the system. During this maneuver, the pilot observed the fuel flow indicator oscillating between 3 and 4 gallons. Immediately following this observation, the aircraft struck a tree approximately nine meters in height. The collision caused a loss of control, leading the aircraft to impact the ground in an inverted position.
The pilot sustained minor injuries and was able to evacuate the aircraft on his own. There was no post-impact fire.
The investigation
The GRIAA investigation focused on the mechanical state of the engine and the pilot's operational decisions. An inspection of the Continental IO-520-D engine and McCauley propeller revealed no internal mechanical failures, such as seizure or overheating. However, the investigation noted that the propeller showed signs of impact at low power, suggesting a partial loss of engine power during the crash.
While the electrical and ignition systems were in good condition, the fuel system components were heavily damaged by the ground impact, preventing a definitive determination of whether impurities caused the fuel flow fluctuations. The investigation also noted that the aircraft's spray system was functional but was being checked at a critical moment of low altitude.
Findings
- The primary cause of the accident was the collision with an obstacle during a low-altitude flight while the pilot was attempting to verify the intermittent operation of the spray system.
- A contributing factor was a partial loss of engine power, likely caused by an undetermined malfunction in the fuel system.
- The pilot failed to execute emergency procedures, specifically the requirement to discharge the chemical payload to gain altitude and lift during an engine anomaly.
- The pilot experienced a loss of situational awareness due to focusing on the fluctuating fuel gauge while maneuvering at extremely low altitude.