Incident Overview
A pilot flying a localizer approach through a 1,200-foot overcast was cleared for the option and chose to land straight ahead with a 6-knot tailwind. The aircraft touched down about 1,500 feet down a 4,500-foot runway. During the landing rollout, the pilot discovered she had almost no toe brake pressure. Attempts to pump up brake pressure using the emergency handle yielded no significant pressure.
Runway Excursion
The airplane continued beyond the end of the runway and entered a brook. Post-incident examination of the wreckage revealed no ruptures in the hydraulic lines. However, hydraulic fluid was found pooled under the rudder pedals, and both brake cylinders were leaking. No brake pressure could be established using the toe brakes, and the emergency hand brake required four pumps before any toe brake pressure developed.
Maintenance History
The airplane had undergone maintenance three months prior to the incident, which included bleeding the brake system and replenishing the brake fluid reservoir.