What happened
On October 14, 2020, an Antonov AN-32A, registration OB-2120-P, was operating a cargo flight from Lima to Iquitos, Peru. During the approach to runway 06 at Iquitos International Airport, the crew encountered turbulence and noted a difficulty in maintaining control due to an asymmetry in engine power.
Upon touchdown, the pilot adjusted the throttle levers to the minimum ground setting and instructed the co-pilot to disconnect the propeller stops to utilize reverse thrust for braking. At that moment, the aircraft experienced an uncontrollable leftward turn. The aircraft veered off the runway, traveling approximately 325 meters through vegetation and across a drainage ditch. The impact with the terrain caused the separation of the right main landing gear, the number two engine, and a significant portion of the right wing. The structural failure led to a fuel leak that ignited a fire in the wing area. The airport' and local emergency services responded immediately to control the fire and evacuate the crew and one passenger.
The investigation
The investigation conducted by the CIAA examined the flight sequence, the aircraft's structural damage, and the crew's actions. Investigators analyzed the aircraft's movement after touchdown and the mechanical failures that occurred during the excursion. The investigation noted that the aircraft suffered total damage, as the structural integrity of the airframe was compromised beyond the possibility of repair. The investigation also reviewed the crew's attempt to counteract the leftward yaw by applying rudder pressure, as evidenced by the displacement of the vertical stabilizer rudder to the right.
Findings
- The primary cause of the runway excursion was the loss of directional control following the disconnection of the propeller stops at a speed exceeding the established limits.
- The asymmetric thrust produced by the propellers during the braking maneuver created an uncontrollable turning moment toward the left.
- The aircraft's excursion into the drainage ditch and uneven terrain resulted in the separation of the right engine, right main gear, and right wing section.
- A fuel spill during the structural failure of the wing led to an intense fire at the wing root.