What happened
On July 26, 2022, at approximately 16:55 local time, a Laviasa PA 25-260 was performing agricultural spraying operations over a rice field in San Luis de Palenque, Casanary, Colombia. While the pilot was executing a maneuver to level the aircraft following a descent at 15 meters altitude, the right wing suffered a structural failure.
The loss of structural integrity caused the aircraft to roll along its longitudinal axis and strike the terrain in an inverted position. The aircraft slid 80 meters before coming to a stop against a tree. A post-impact fire ensued, consuming approximately 90% of the airframe. The pilot sustained serious injuries from the impact and the fire but managed to evacuate the wreckage independently and was assisted by a local resident.
The investigation
The GRIAA investigation, which included technical assistance from Argentina's JST and Brazil's CENIPA, focused on the sequence of the structural failure and the maintenance history of the aircraft. Investigators examined the condition of the wing spars and the impact of agricultural flight profiles on the airframe. The analysis included laboratory testing of the failure to determine the origin of the cracks and the role of corrosion and plastic deformation in the spar components.
Findings
- The primary cause of the accident was the structural separation of the right wing due to a sudden overload during a leveling maneuver.
- The failure originated from fatigue in one of the holes of the right wing's front spar, which triggered crack propagation through areas weakened by corrosion and plastic deformation.
- Continuous agricultural spraying operations had progressively reduced the mechanical strength of the spar structures, making them unable to withstand the stresses applied during the maneuver.
- Contributing factors included the high-load demands of the specific spraying technique, specifically a high-entry approach over an obstacle followed by a sharp control input to level the aircraft.
- A lack of specialized inspection procedures or additional maintenance guidelines from the manufacturer regarding the inspection of the wing spars was also identified.