On December 4, 2007, a Robinson Helicopter R22 BETA (registration N70035) operated by Tim Roland was involved in an aviation accident near Gainesville, FL. Investigators recorded the probable cause as: The pilot's failure to follow the published emergency procedure. Contributing to the accident was a malfunction of the clutch assembly. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter on a solo cross-country flight experienced an intermittent clutch light and subsequent loss of rotor rpm, leading to a hard landing and rollover after the pilot did not follow the emergency procedure to pull the clutch circuit breaker.
Accident Narrative
A helicopter pilot, who was receiving flight instruction to add a rotorcraft rating to his certificate, was conducting a solo cross-country flight. After approximately 1 hour and 20 minutes of cruise flight, the pilot observed an intermittent illumination of the clutch light and noticed a perceived loss of altitude. He responded by resetting the circuit breaker and increasing collective pitch to regain altitude. Subsequently, he perceived a loss of rotor rpm and gradually lowered the collective to keep the rotor rpm within the normal operating range. When the helicopter descended to about 150 feet above ground level, the pilot could no longer maintain rotor rpm and initiated an autorotation. He selected an empty parking lot for the landing, but the helicopter landed hard, bounced, and rolled onto its side. The pilot reported that the engine was running both before and after ground contact, and he noted no deficiencies in the helicopter's handling characteristics.
Findings and Testing
Functional testing of the clutch assembly revealed that its rigging and operation met factory specifications, but the engagement cycle time exceeded the factory limit. The pilot stated that he had reset the circuit breaker and continued adjusting collective pitch in an attempt to regain altitude and rotor rpm. The Pilot's Operating Handbook specifies that the emergency procedure for a clutch light indication directs the pilot to pull the clutch circuit breaker and land immediately.