Incident Overview
A pilot reported that after performing a simulated rope break maneuver while towing a glider, he maneuvered the airplane to the runway and landed normally. During the landing roll, the airplane yawed to the left. The pilot applied right rudder inputs to correct the yaw, but they were ineffective. He then quickly applied the right brake but felt no brake pressure in the pedal. He pressed the brake pedal four to five times as the aircraft continued to yaw. Subsequently, the airplane ground looped to the left.
Damage
The airplane sustained substantial damage to the right wing and the fuselage.
Pilot Observations
The pilot reported that when he applied the right brake, he heard the pedal click against something behind it, creating a metallic sound.
Post-Accident Examination
A post-accident examination of the right brake system components revealed that the brake disc and brake pads were within limits. However, the aluminum hydraulic brake line tube, which runs along the aft edge of the gear leg from the brake caliper toward the master cylinder, was broken about halfway down the gear leg, under the retaining bracket. The retaining bracket was canted, and the brake line and rubber padding had been secured with a zip tie. There were no signs of impact damage at the break.
Manufacturer's Statement
In a statement dated October 14, the airplane's type certificate holder reported to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) that at the point where the zip tie had been installed, the brake line was supposed to be held in place by a green bracket, with a small section of rubber tube protecting the line from direct contact with other metal parts. The green bracket should be positioned perpendicular to the aft contour line of the gear leg.