What happened
On September 1, 2020, a Cessna A188B agricultural aircraft, registered as HK-1644, was performing its first spray flight of the day from the San Isidro airstrip in Puerto López, Meta. The aircraft was operating at a takeoff weight of 3,362 lbs, carrying 20 gallons of fuel and 10 and 100 gallons of chemical mixture.
During the takeoff roll on runway 08, the pilot executed a rotation at 75 MPH. Shortly after liftoff, the pilot encountered a cluster of trees approximately 70 meters ahead of the runway threshold. To avoid these obstacles, the pilot maintained a high angle of attack and initiated a right-hand turn. During this maneuver, the pilot noted a perceived lack of engine performance. At approximately 200 feet AGL, the aircraft began losing altitude. The pilot attempted an emergency discharge of the chemical load, but the aircraft continued to descend, impacting the terrain approximately 1,300 meters from the runway threshold.
The impact caused the aircraft to flip onto its back, resulting in substantial structural damage and an immediate fire that consumed roughly 50% of the airframe. The pilot successfully evacuated the aircraft with minor injuries.
The investigation
The GRIAA investigation focused on the engine's performance and the aircraft's aerodynamic state during the climb. Investigators examined the engine's power plant and found that the left magneto was malfunctioning due to points that were out of manufacturer calibration limits and an improperly adjusted assembly. This malfunction likely caused a partial loss of engine power.
Furthermore, the investigation looked into the operational environment at the San Isidro airstrip. It was established that a group of trees reaching 62 feet in height stood near the takeoff path, posing a significant hazard for aircraft operating at maximum takeoff weight. The investigators also examined the operator's safety practices, specifically regarding the aircraft's cockpit configuration.
Findings
- The primary cause of the accident was a loss of lift and control at a low altitude following takeoff, driven by insufficient power and airspeed during the initial climb, which was exacerbated when the pilot exceeded the critical angle of attack during a turn.
- A malfunctioning left magneto caused a partial loss of engine power.
- The operator had established a routine practice of deactivating the aircraft's stall warning system to prevent pilot distraction during spraying operations, which deprived the pilot of a critical warning during the stall sequence.
- The presence of 62-foot trees near the takeoff path created a continuous obstacle hazard.
- The pilot failed to recognize the imminent stall and did not take immediate corrective actions.