Sikorsky S-76A Tail Rotor Failure During Training Flight at London International Airport

Incident Overview and Flight History On the day of the incident, two qualified pilots departed from London International Airport in Ontario at approximately 1530 EDT in a Sikorsky S-76A helicopter, registration C-GIMM, serial number 760044. The aircraft was operated by the Emergency Medical Services Division of Canadian Helicopters Limited. The flight was conducted for crew training purposes, specifically to prepare for a pilot proficiency check. The crew performed multi-engine exercises in the local area before returning to the airport to conduct simulated one-engine-inoperative exercises involving take-offs and landings across the button of Runway 27. During the second approach, the pilot flying raised the collective in the normal manner for both engines operative, unaware that an engine failure had been simulated on the number 2 engine. This resulted in a decay in rotor speed and a touchdown at a higher than normal rate of descent. The pilot not flying attempted to regain power from the simulated inoperative engine, but the number 2 engine did not respond quickly enough to avoid a hard landing. The tail boom of the helicopter buckled on impact, bringing the tail rotor drive shaft into contact with internal structure. The crew was unaware of the structural damage but felt a buzz in the anti-torque pedals, which might have indicated that a main rotor blade had hit the tail rotor. Consequently, they terminated the flight and began to ground taxi back to the company ramp. While taxiing, the tail rotor failed when the drive shaft was cut through. The accident occurred at approximately 1630 EDT.