Maule MX-7 N114MK accident near Roche Harbor, Washington

Probable cause

A damaged brake master cylinder piston rod, which resulted in a landing with the left brake applied. The damage was a result of normal parking brake operation.

NTSB analysis

The pilot/owner was conducting a short personal flight in the tailwheel-equipped airplane. The departure, flight, and approach to the paved 30-ft by 3,593-ft runway were all normal, and the wind was calm. The pilot made a normal and uneventful three-point landing, but immediately after touchdown, the airplane veered sharply to the left. The pilot applied full right rudder and some right brake, but he was unable to keep the airplane on the runway. The airplane departed the left side of the runway, traversed an adjacent grassy area, and struck a drainage ditch about 50 ft from the runway. The airplane sustained substantial damage.

Postaccident examination of the airplane revealed that the left brake master cylinder piston rod was damaged such that it could prevent release of brake pressure. The damage was attributed to normal operation of the parking brake, during which a locking lever formed multiple cuts and ridges in the rod, and, under certain conditions, could prevent the free travel required for release of brake pressure. Although the damage to the piston rod would have been detectable by a detailed inspection, its nature, extent, and location limited its ability to be detected under the scope of a typical annual inspection. In addition, the pilot had not had any previous occurrences of dragging or stuck brakes, which would have warranted a more detailed inspection of the brake system components. Once airborne, the pilot had no way to detect, prevent, or eliminate a locked wheel due to this condition.

Text from the NTSB. Open the NTSB docket for WPR12LA207 for the full record.