What happened
On October 21, 2015, a Cessna 210R, registration PT-LKW, was performing a private flight departing from Jardim Airport (SSIJ) in Mato Grosso do Sul, Brazil. During the takeoff roll, specifically at the moment of rotation, the pilot's seat unexpectedly slid backward due to inertia. This sudden movement caused the pilot to lose physical contact with both the control yoke and the rudder pedals, rendering the aircraft unsteerable. As the seat moved, the aircraft's center of gravity shifted, leading to an increased angle of attack and a subsequent loss of lift at a low altitude. The aircraft struck the runway pavement and veered off to the left side of the runway, resulting in substantial damage to the aircraft. The pilot sustained minor injuries.
The investigation
CENIPA investigators examined the seat mechanism, which operates on a rail system designed to allow ergonomic adjustments via a locking pin and holes. Although the aircraft had undergone a 200-hour inspection just six days prior to the accident, the investigation revealed that the aircraft was not in compliance with mandatory safety directives.
Specifically, investigators found that the locking pin and the rail holes had excessive wear, exceeding the limits established by Airworthiness Directive (AD) 2011-10-09. Furthermore, the investigation identified that the secondary seat stop, intended to prevent uncontrolled rearward movement, had been bypassed or improperly installed. The pins required for the secondary stop installation, as prescribed by Service Bulletin SEB07-5 Revision 6, had been incorrectly replaced with cotter pins, failing to provide the necessary secondary restraint.