What happened
On June 7, 2014, an Antonov AN-26B, registration HK4728, was performing a mixed cargo and passenger flight from San José del Guaviare to Mitú. During the takeoff roll on runway 01, the pilot experienced a heavy vibration as the aircraft approached V1 speed. This vibration was caused by the failure of the number two main landing gear tire.
Upon detecting the vibration, the pilot attempted to verify the condition by adjusting flight controls, which caused the vibration to intensify. The pilot subsequently decided to abort the takeoff. During the deceleration process, the aircraft veered sharply to the right, exiting the runway and entering the safety area. The aircraft's right propeller struck an automated weather station antenna, tearing it from its base, and then struck the roof of a security guard booth. The impact caused the sudden stoppage of the right engine and significant damage to the propeller blades and fuselage.
All 16 occupants—comprising three crew members and 13 passengers—were uninjured and evacuated the aircraft on their own.
The investigation
The GRIAA investigation focused on the sequence of events following the tire burst and the subsequent loss of directional control. Investigators examined the cockpit actions and the mechanical response of the braking system. The investigation established that while the tire failure initiated the emergency, the aircraft's deviation from the runway centerline was exacerbated by an unauthorized action within the cabin.
Specifically, the investigation found that a technician on board, acting without instructions from the pilot, applied the aircraft's emergency brakes asymmetrically. This unauthorized intervention inhibited the flight crew's ability to use the pedal brakes effectively, preventing them from correcting the aircraft's trajectory and leading to the excursion.