What happened
A commercial certificated pilot was conducting a flight under Title 14 CFR Part 91 to deliver supplies to a lodge situated near a private, unpaved airstrip. The strip measured approximately 1,200 feet in length and featured a dirt surface. Upon touchdown, the pilot reported an immediate failure of the left brake system.
As the aircraft approached the end of the available runway, the pilot attempted to execute a 180-degree turn to stop or reposition the airplane. The braking deficiency prevented effective directional control, causing the aircraft to ground-loop. During this uncontrolled maneuver, the right wing struck the ground, resulting in significant structural damage to that specific airframe component.
The investigation
Post-accident examination confirmed the mechanical nature of the incident. The pilot noted that prior to this event, he had been managing a known issue with the left brake system. Specifically, the master cylinder was leaking, necessitating frequent pumping of the brake pedal to maintain hydraulic pressure and braking effectiveness on previous flights.
Findings
The accident sequence was directly linked to the failure of the left brake during the landing roll. The pilot's inability to maintain directional control led to the ground-loop and subsequent impact with the ground. The known mechanical defect, a leaking master cylinder requiring constant manual intervention, was a critical contributing factor to the loss of braking capability on the left side.