We began by asking what is the risk of a helicopter accident, and how does that risk compare to risk associated with other modes of travel. When we compared helicopters to airliners, we found that airliners have an accident rate (per departure) about one tenth that of helicopters, no surprise there. We were somewhat surprised that about 10% of accidents involve fatalities for both airliners and helicopters. This means that fatal accidents are about ten times more likely for helicopters, because accidents generally are about ten times more likely, but the accidents themselves are neither more nor less fatal.
Of course, airliners and helicopters are apples and oranges, differing in size, speed, flight environment and pilot population. General aviation aircraft as a group are much more similar to helicopters, minus the rotating parts. And their accident rate is more similar too. In fact the accident rate (per hour) for helicopters and general aviation is nearly identical, about eight accidents per 100,000 hours. Again about one tenth of accidents involve fatalities.
So maybe smaller vehicles are just more dangerous. Then what about cars? They are small. And we all know that the most