Cessna 182K N3094Q accident near Tooele, Utah

Probable cause

Loss of brake pressure to both sets of brakes during taxi due to failed brake caliper O-ring seals, which resulted in a loss of directional control.

NTSB analysis

During an instructional flight, the student pilot reduced engine power to idle and applied the brakes as the airplane taxied toward the end of the runway. However, the airplane did not respond to this brake application. The flight instructor assumed control of the airplane and applied brakes, but the airplane still did not respond. While the flight instructor was attempting to mitigate the situation, the airplane exited the right side of the taxiway and impacted a ditch.

Examination of the airplane’s brake system revealed a leak on both main landing gear brake caliper O-ring seals. Both brake calipers were removed and disassembled, and both O-ring seals were flattened, consistent with excessive use and wear. The flattened O-ring seals prevented the proper seal within the brake calipers, which resulted in the complete loss of brake fluid. The complete loss of brake fluid prevented the use of the airplane brakes, which caused a subsequent loss of directional control.

Text from the NTSB. Open the NTSB docket for WPR22LA323 for the full record.