Landing and Brake Failure
During the landing rollout on a 3,100-foot-long by 60-foot-wide runway, the pilot applied full reverse thrust after touching down within the first quarter of runway 07. As the airplane decelerated and approached the last third of the runway, reverse thrust was discontinued. The pilot then pressed the brake pedals; the right pedal went to the floor, and the airplane veered to the left.
Corrective Actions and Excursion
Approximately three-quarters of the way down the runway, the pilot feathered the right propeller and applied power to the left engine. Despite these efforts, the airplane continued veering left, eventually entering a ditch, which collapsed the nose landing gear.
Post-Accident Inspection
A subsequent examination of the brake system revealed that the right gear brake pads and disc were in good, serviceable condition. However, the O-rings in the brake housing were distorted in shape. When the brake system was pressurized, hydraulic fluid leaked past the distorted O-rings. After installing new O-rings in the right brake assembly and pressurizing the system, no leaks were noted, and the brake system was deemed airworthy.
Maintenance History
The airplane was maintained under an approved inspection program. The most recent inspection had occurred approximately 110 flight hours before the accident flight.