Amateur-built Smith AVN Replica SU N712AZ accident near St. Johns, Arizona

Probable cause

The pilots’ failure to maintain directional control when the right brake locked up during the landing roll for reasons that could not be determined because postaccident examination did not reveal any anomalies that would have precluded normal operation.

NTSB analysis

The pilot had recently purchased the airplane and was receiving instruction in it. The pilot reported that the day before the accident, during landing, the left brake became less responsive than the right, and the airplane veered off of the runway but incurred no damage. The pilot and his flight instructor then bled the brake lines. This was followed by taxi and touch-and-go landing checks with no anomalies noted. The following morning the brakes were tested again and were operational. During the fourth landing that morning, the right brake locked up, and the airplane swerved to the right and nosed over. Although the flight instructor indicated that he had signed off the pilot for his tailwheel endorsement the day of the accident, he did not hold a current airman medical certificate. Additionally, the instructor reported that he did not remain on the flight controls with the pilot during the landings. Postaccident examination of the brake system revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR12LA135 for the full record.