What happened
The incident occurred during the rollout phase of a full-stop landing. As the pilot applied the brakes to slow the aircraft, the right brake system failed completely. Unable to stop on the paved surface, the pilot attempted to maneuver the aircraft off the runway in an effort to bring it to a halt naturally.
During this evasive maneuver, the right landing gear strut collapsed under the stress or uneven loading. The aircraft then slid across the ground until it came to rest after striking a fence.
The investigation
A physical examination of the aircraft revealed significant mechanical issues with the braking system. Inspection of the right brake assembly showed that both the inner and outer brake pads were extremely thin, with some portions worn completely away.
Further inspection uncovered that the O-ring seal around each brake cylinder was protruding from the cylinder assembly. The right tire exhibited heavy staining consistent with hydraulic fluid leakage. Maintenance records indicated a logbook entry dated January 25, 1985, stating that brake linings and seals for both brakes had been replaced during that inspection.
Findings
The evidence points to a failure in the braking system maintenance or assembly. The protruding O-ring seals likely compromised the hydraulic integrity of the brake cylinders, leading to the loss of braking pressure on the right side. The worn brake pads further reduced the effectiveness of any remaining braking force.