Amateur-built DM-1 N75EW accident near Salters, South Carolina

Probable cause

A hard landing following an autorotation that resulted from the separation of the red main rotor blade cap that led to the uncontrolled movement of the cyclic, autorotation and a hard landing.

NTSB analysis

The pilot stated that while maneuvering at 800 feet above ground level, the homebuilt helicopter pitched up and slowed to 40 knots. He entered autorotation and the helicopter impacted the ground. Examination of the wreckage by a Federal Aviation Administration inspector revealed the end cap of the main rotor blade was missing. The inspector attributed the separation to excessive blade bowing due to taking off above maximum gross weight, resulting in a shift in the rotor blades center of gravity. The inspector also stated that the change of the blade's center of gravity created or aggravated the main rotor blades' twisting and balance reactance to such a level that the end cap of the red blade detached from the blade. This blade cap departure created an imbalance of the rotor blade that led to an out of balance and track condition of the main rotor resulting in a pitch up of the aircraft and loss of longitudinal control. Review of the helicopter logbook revealed the condition inspection was 8 months past the required 12-month inspection interval.

Text from the NTSB. Open the NTSB docket for ERA09LA107 for the full record.