NTSB Factual Report

On June 1, 2010, about 1900 Pacific daylight time, an experimental Airborne Windsports PTY LTD Edge X, N354MB, collided with terrain during landing at Alturas, California. The student pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The student pilot sustained minor injuries, and the certified flight instructor (CFI) was not injured. The airplane sustained substantial damage to the wing and wire support bracing. The local instructional flight departed Alturas about 1800. Visual meteorological conditions prevailed, and no flight plan had been filed.

The CFI stated that the student had been practicing touch-and-go landings, and this was to be a final full stop landing. The airplane touched down safely, and was rolling straight at 30 miles per hour. Suddenly and without warning, the wing rolled severely to the left, and struck the ground. The wing crumpled, and dug into the surface. The airplane rolled onto its left side, and skidded to a stop on the runway. The CFI then shut off the ignition, magnetos, and fuel valve.

The CFI indicated that post flight examination revealed that the right rear mast support cable snapped about 3 inches above its lower attachment point. This was at a point where the cable enters a swedge. The cable is covered by the manufacturer with an opaque plastic cover, similar to shrink tubing. He stated that they observed no discrepancies on the cables, welds, engine, wing, suspension, or other components during preflight. They had completed about 12 landings during the day with no indications of a potential problem.

A Federal Aviation Administration (FAA) inspector examined the wreckage, and observed that the right mast to landing gear support cable was broken at the copper compression swedge. There appeared to be some bluish green corrosion on the swedge.

NTSB Probable Cause

Fracture of a mast support cable due to corrosion, which resulted in a loss of control during the landing roll.