Primary finding
Probable cause
The pilot’s inability to maintain directional control after landing with an excessive ground speed due to a tailwind which, resulted in a severe shimmy which subsequently damaged a hydraulic brake line.
Investigator assessment
Analysis narrative
The pilot in the experimental amateur-built tricycle landing gear equipped airplane reported that, he was not aware that a 10-mph tailwind existed during landing. He normally touches down at 90 mph, however with the tailwind, the airplane’s ground speed was 104 mph when the airplane touched down and a severe shimmy ensued. The pilot applied the brakes, however the left side brake failed, and the airplane veered right, exited the right side of the runway, and subsequently impacted a hangar. The airplane sustained substantial damage to the left wing and engine mounts. Post-accident examination of the airplane revealed that the left main landing gear wheel pant inboard bracket rivets failed, and the wheel pant severed the plastic hydraulic brake line.