The pilot reported that he had landed at the mustering camp and prior to disembarking had placed a rubber strop over the collective lever. This was necessary as the lever would rise if no restraint was applied to it. He wanted a "relief break" and to deliver a parcel to one of the men at the camp. Having been out of the helicopter for a few minutes as he started to walk back to it the aircraft lifted off the ground rolled and came to rest on its left side. When he was able to return to the cabin he found that the strop was no longer on the collective lever. The pilot claimed a total experience of 7500 hours including 200 on type. He has flown a total of 250 hours in the last 90 days 80 hours on the lst 30 days and 6 hours on the last 24 hours. These times included 17 hours on type in the last 30 days and 6 hours on type in the last 24 hours. During conversation the pilot reported that he was aware of three incidents in Queensland and two in Western Australia where R22's without the pilot in the aircraft had performed a similar manoeuvre. There is no manufactured collective lever restraint system in the aircraft and each operator makes up his own means of tie-down because the practice of leaving the helicopter when the engine is running is quite common.
