Flight History
On 26 July 2022, the Laviasa PA 25-260, registration HK1207, was scheduled by an agricultural aviation company for spraying operations over rice fields. The pilot began flights at 06:00 local time from El Recreo airstrip (SQEQ). After multiple sorties from different airstrips, the final series of five flights was planned from SQEQ for 64 hectares of rice. At 16:30 local time, the pilot departed for the fourth flight of this series, carrying 100 gallons of chemical product and 24 gallons of fuel. During a spraying pass over a 20-hectare area, while at about 15 meters altitude with flaps retracted, the aircraft was descending to approach the field. As the pilot controlled pitch to level the aircraft, the right wing structurally separated.
Injuries and Aircraft Damage
The single pilot, the sole occupant, sustained serious injuries from the impact and subsequent fire. The aircraft rolled about its longitudinal axis after wing separation and struck the ground inverted, sliding 80 meters before stopping. A fire ensued, consuming approximately 90% of the aircraft.
Weather and Conditions
The accident occurred at 16:55 local time (21:55 UTC) in daylight and visual meteorological conditions (VMC).
Structural Failure Details
Investigation determined that the right wing separation originated from a fatigue failure at one of the holes in the front spar. This fatigue crack propagated through areas with corrosion and plastic deformations. Progressive reduction of the mechanical properties of the spar structures over repeated spraying flights compromised their ability to withstand applied stresses. The leveling maneuver during the spraying pass caused a sudden overload failure of the spars, leading to loss of structural integrity of the right wing.
Probable Cause
The probable causes were: collision with terrain after loss of control due to structural separation of the right wing during a spraying flight; fatigue failure generated in one hole of the right wing front spar that triggered crack propagation in areas with corrosion and plastic deformations; and progressive reduction of mechanical characteristics of the spar structures during continuous spraying flights, compromising their ability to withstand stresses, resulting in sudden overload failure of the spars due to the leveling maneuver, causing loss of structural integrity of the right wing.
Contributing Factors
Contributing factors included the demands of the spraying technique used, involving a high entry due to an obstacle and an abrupt leveling action that increased the structural load factor on the wings; and the absence of additional inspection procedures and guides from the manufacturer for inspecting and correcting wing spars on the Laviasa PA 25-260.
The investigation issued four safety recommendations.