Sikorsky UH19 N955TC accident near Brewster, Washington

Probable cause

A reported mechanical malfunction and a hard landing for reasons that could not be determined based on available evidence.

NTSB analysis

The pilot-in-command (PIC) was evaluating another pilot as a new job applicant. While the applicant-pilot was manipulating the helicopter controls, the PIC heard a “bang” and noted an overspeed indication on the tachometer. He subsequently took control of the helicopter and performed an autorotation that resulted in a hard landing, which substantially damaged the helicopter. The Federal Aviation Administration and operator surmised that the main drive line system clutch and torque converter failed, which resulted in the engine overspeed. However, the operator did not respond to investigators or submit a NTSB Form 6120.1, Pilot/Operator Aircraft Accident Incident Report, nor was a follow-up examination of the helicopter able to be scheduled and performed by the NTSB investigator. Due to the operator’s lack of cooperation during the investigation, the NTSB investigator was unable to definitively determine the cause of the accident.

Text from the NTSB. Open the NTSB docket for WPR19LA168 for the full record.