What happened
The aircraft was landed downwind under light wind conditions by a student pilot. During the rollout phase, after normal braking had been applied to decelerate, the aircraft began to drift toward the right side of the runway. In response to this drift, the student pilot applied the left brake pedal. Simultaneously, the certified flight instructor (CFI) also applied corrective left brake input.
At the moment both pilots applied left brake pressure, the left brake connecting rod failed due to overload. Because the right brake remained applied while the left system failed, the aircraft swerved sharply to the right. This asymmetric braking force caused the aircraft to ground loop and subsequently nose over.
The investigation
The investigation focused on the mechanical failure of the braking system during the critical phase of landing rollout. Examination revealed that the left brake connecting rod had failed in overload. The failure occurred precisely when corrective braking inputs were made by both the student pilot and the CFI to counteract the rightward drift.
Findings
Several factors contributed to the accident sequence. The initial decision to land downwind, although in light wind conditions, set the stage for potential directional control challenges. The primary mechanical failure was the left brake connecting rod failing in overload during corrective braking. This mechanical failure, combined with the continued application of right brake pressure, resulted in a violent swerve to the right, leading to the ground loop and nose-over.
Safety message
This incident highlights the critical importance of monitoring braking system integrity during high-stress landing rollouts, particularly when corrective inputs are required. It also underscores the need for clear communication and coordinated control inputs between student pilots and flight instructors during downwind landings.