What happened
The pilot had previously landed on a runway that had been plowed, resulting in surface conditions of hard-packed snow and ice. While taxiing for a turnaround at the end of that runway, the pilot believed the right-hand brake became hydraulically locked due to the engagement of the parking brake mechanism on that side, despite the pilot stating the parking brake handle was never pulled.
The subsequent takeoff from the icy runway appeared normal, and the pilot remained unaware that the brake was in a locked condition. However, upon touchdown at Hailey, the airplane immediately veered violently to the right. The right-hand brake remained locked during this maneuver, causing the aircraft to swerve to the right before ultimately nosing over.
The investigation
The investigation focused on the mechanical state of the braking system. It was determined that the parking brake locking lever on the right brake cylinder was in its overcenter position, which resulted in the brake being locked.