What happened
On September 26, 2022, at approximately 08:30 local time, an Air Tractor AT-301 was conducting an aerial application mission over an avocado plantation in the Llay-Llay sector, San Felipe, Valparaíso Region. The aircraft, operated by a commercial aerial service, was performing fertilization maneuvers when it began an uncontrolled descent and a left-hand turn. During this maneuver, the aircraft lost sufficient lift to maintain flight, causing it to strike avocado trees. Following the initial impact, the aircraft continued moving across the plantation for approximately 48 meters before coming to a final rest on the terrain.
The investigation
DGAC Chile investigators examined the wreckage and flight records to determine the sequence of events. The investigation focused on the aircraft's mechanical condition, the pilot's actions, and the environmental factors. Physical inspection of the Air Tractor AT-301 revealed significant structural damage, including a fractured left wing tip, deformed wing edges, and a detached main landing gear. The engine area showed damage from impacts with branches, and the propeller blades were deformed.
Investigators also examined the fuel system, discovering that the left fuel tank was empty due to a fractured nipple that had allowed fuel to spill onto the ground. The right tank still contained fuel. The investigation confirmed that the aircraft's maintenance records were up to date and that the operator held a valid Air Operator Certificate (AOC). The pilot, a commercial pilot with over 2,500 flight hours, sustained serious injuries during the accident.
Findings
- The aircraft experienced a loss of lift during a low-altitude maneuver, leading to a stall-like condition.
- The aircraft's weight at takeoff was approximately 5,203 pounds, which exceeded the certified maximum takeoff weight of 5,000 pounds.
- A fractured nipple on the left fuel tank caused the loss of fuel from that tank during the flight or impact.
- The aircraft was operating at a very low altitude, consistent with standard aerial application procedures, which left no margin for recovery once the descent began.