What happened
During a recurrent training flight at London International Airport, Ontario, two pilots were conducting multi-engine and one-engine-inoperative (OEI) exercises in a Sikkersy S-76A, registration C-GIMM. The flight, operated by the Emergency Medical Services Division of Canadian Helicopters Limited, involved simulating engine failures during approaches to a runway.
On the second approach, the pilot not flying (PNF) simulated a failure of the number 2 engine by reducing its power to flight idle. However, due to a lack of clear communication and a misleading torque gauge reading, the pilot flying (PF) believed both engines were producing sufficient power. As the helicopter reached approximately 35 feet above the ground, the PF initiated a flare using a technique intended for two-engine operations. This caused the rotor speed to decay, leading to a hard landing with a high rate of descent.
Upon impact, the tail boom of the aircraft buckled, causing the tail rotor drive shaft to strike the internal structure. While the crew attempted to taxi the aircraft back to the company ramp, the damaged drive shaft eventually severed, resulting in the failure of the tail rotor.