What happened
On April 8, 2017, an AT-802 agricultural aircraft, registration PR-FOG, was performing pesticide application over a corn plantation at Fazenda Ribeirão, in Ribeiro Gonçalves, Piauí. The aircraft was flying at a very low altitude, approximately 5 meters, while transitioning between two cultivation areas.
During the flight, the pilot attempted to program the GPS unit. To facilitate this, the pilot moved his right hand from the control stick to the GPS, using his left hand to fly the aircraft. During this maneuver, the aircraft began a descent that went unnoticed. The aircraft struck the ground in a nose-down attitude, with the propeller tips making initial contact with the soil. The aircraft then slid 378 meters through the cornfield, resulting in substantial damage to the landing gear, engine, propeller, and fuselage sections.
The investigation
CENIPA investigators established that the pilot, an experienced professional with 2,000 flight hours, was flying under visual flight rules in favorable weather conditions. The investigation focused on the pilot's cockpit management and the aircraft's trim configuration.
Investigators found that the pilot had a habit of trimming the aircraft into a nose-down attitude to increase control sensitivity during agricultural operations. Furthermore, the investigation revealed that the pilot's flight helmet was not properly secured, as the chin straps were loose, which caused the helmet to dislodge upon impact. The pilot sustained light injuries.
Findings
- Distracted flight management: The pilot's focus on programming the GPS diverted attention from essential flight monitoring, leading to a loss of situational awareness.
- Unsafe trim configuration: The practice of maintaining the aircraft in a nose-down trim significantly contributed to the sudden descent when the pilot's control of the stick was compromised.
- Inadequate risk assessment: The pilot failed to properly evaluate the risks of performing complex tasks like GPS programming while flying at extremely low altitudes.
- Improper use of PPE: The loose straps on the flight helmet contributed to the helmet's displacement during the impact.