What happened
On April 23, 2017, an AT-401B agricultural aircraft, registration PT-WVY, was attempting to depart from a private landing strip located at the Usina Santa Terezinha in Mariluz, Paraná. The aircraft was performing a local flight for the application of pesticides.
During the takeoff roll, the aircraft utilized the entire length of the 800-meter dirt runway but was unable to achieve flight. Upon reaching the end of the runway, the aircraft overran the threshold and collided with a nearby sugarcane plantation. The impact caused substantial damage to the aircraft's structure, specifically affecting the landing gear, tail cone, and wings. The pilot was uninjured.
The investigation
CENIPA's investigation established that the aircraft was operating at a weight of 3,537.2 kg, which was 815.2 kg above the maximum takeoff weight (MTOW) of 2,722 kg. The aircraft was fully loaded with 476 liters of AVGAS and 1,008 kg of agricultural product in the hopper.
Investigators examined the pilot's configuration of the aircraft and found that, in an attempt to gain lift, the pilot fully extended the flaps. This contradicted the manufacturer's operational manual, which prescribes a 10-degree flap setting for short-field takeoffs with a full hopper to optimize the lift-to-drag ratio. The full extension of the flaps increased aerodynamic drag and decreased airspeed, making takeoff impossible. Additionally, the investigation noted that the pilot did not consider the option of jettisoning the hopper load to reduce weight during the emergency situation.
Findings
- Inappropriate flight control application: The pilot's decision to use full flap deflection increased drag and prevented the aircraft from rotating.
- Improper flight planning: The takeoff was planned with a weight significantly exceeding the certified maximum takeoff weight.
- Pilot judgment and experience: The pilot, while qualified, had only 32 hours of experience in the AT-401B model, which may have influenced the ineffective decision-making during the takeoff roll.
- Failure to mitigate risk: The option to jettison the agricultural load to decrease weight was not utilized.
Safety action
CENIPA issued recommendations to the National Civil Aviation Agency (ANAC) to engage with the operator regarding the risks of non-compliance with operational manuals, particularly concerning short-field takeoff procedures and the importance of managerial oversight in flight planning.