Cessna 170A N5406C accident near Anchorage, Alaska

Probable cause

The fracture of a hydraulic brake line fitting due to incorrect installation of the brake line by the pilot/owner, which resulted in a loss of brake pressure and subsequent loss of directional control during the landing roll.

NTSB analysis

The pilot was landing his tailwheel-equipped airplane on a dry, gravel runway at the conclusion of a local area flight. After landing, the pilot applied the brakes to slow the airplane, and, while depressing both brake pedals, the left brake pedal unexpectedly went to the floor. The airplane swerved to the right, went off the right side of the runway, and nosed over in an area of soft, marshy, wet tundra, sustaining substantial damage to the rudder, left wing, and left aileron. A postaccident examination revealed that a hydraulic brake supply line fitting near the airplane's fuselage had broken, which resulted in a loss of brake pressure to the left brake. The hydraulic brake line was not secured to the landing gear strut as required, which allowed the line to flex and bend at the fitting during flight. The pilot reported that he recently rebuilt the airplane himself.

Text from the NTSB. Open the NTSB docket for ANC11CA095 for the full record.