1. 1 Presented to: International Helicopter Safety Symposium, September 26-29, 2005, Montreal Engineering Assumption versus Operational Reality: Repeated Lift Operation.

2. 2 Heli-logging

3. 3 Helicopters work in cycles For pleasure and corporate helicopters there are 4 cycles per hour. For heli-logging and firefighting there are 20 to 30 cycles per hour. Some manufacturers do not accept the facts of cycles nature.

4. 4 Heli-logging as part of Repetitive Lift Operations (RLO) Since the late seventies some helicopters have been dedicated to Repetitive Lift Operations (RLO) and there have been some significant accidents because of component malfunctions. During RLO operations there can be 10 times more events than anticipated as normal operations; There is a significant number of helicopters dedicated to RLO operations.

5. 5 Torque & Hook Weight over Time Pleasure Flight & Anticipated Usage

6. 6 Torque & Hook Weight over Time Heli-logging

7. 7 Torque over time for pleasure and heli-logging

8. 8 Real application versus certification spectrum

9. 9 Aerospatiale 315B Free Wheel Unit

10. 10 S-61 Roller damage

11. 11 S-61 Calm shaft

12. 12 Conclusions There is a need to enhance traceability and history of the critical components. There is a need for common cycle definitions with simple accounting methods. Critical components replacement and maintenance should be based on operational cycles versus flight hours.