Flight Design CTLS N21ZA incident near Elyria, Ohio

Probable cause

The manufacturing defects in the main landing gear leg, which resulted in its eventual failure.

NTSB analysis

The flight instructor reported that the airplane's fixed right main landing gear collapsed during landing. He reported that the landing was "not extraordinarily hard" and that it should have been well within the airplane's typical performance.

Postincident examination of the composite right main landing gear leg revealed several manufacturing defects, including wrinkled layers and layers that terminated at the surface when they should have been continuous, which reduced the landing gear leg's strength and its ability to resist longitudinal cracks. As a result of this investigation, the airplane manufacturer conducted an audit of the subcontractor that manufactured the landing gear legs. The audit revealed that, before the incident, the landing gear manufacturer had become aware of quality issues related to the mold closing process of the landing gear legs during manufacture and had implemented steps to reduce the recurrence of these issues. Based on the available evidence, the manufacturing defects in the composite main landing gear leg likely reduced the leg's load-carrying capacity and resulted in its eventual failure.

Text from the NTSB. Open the NTSB docket for CEN13IA024 for the full record.