I don't know if this is the right section to post this in but as I thought it had an engine this would be most appropriate. What I was wondering was why is it when people get in and out of a helicopter with it's propeller going, that they duck down? The helicopter itself is much taller than a standing person so the blades couldn't chop someone's head off. And as long as the blades are moving they don't dip. is it that the wind force is so strong?
Its just a good habit to get into, not all 'copters are that tall, the smaller two seat jobs, like the Robinson R22, are only slightly taller than a man, and when the blades are slowing the tips do dip down but are still moving too fast to be seen. Considering the damage a blade tip would do if it caught you, I think its just a sensible precaution to duck as you move away from the 'copter body.
I worked on Helicopters and I can assure you that a strong gust of wind can certainly blow a blade down to head height at the tip obviously not at the root. It is called "blade sail".This is why the pilot keeps plenty of revs on if people have to disembark with the engine running.
I prefer the engine stopped thanks !
An additional concern for safety is exiting a helicopter on the uphill side. That's where the ground isn't level, such as remote work sites and one side of the helicopter's landing site is higher or slopes upwards from the skids. In that case, the pilot needs to be aware of passengers going in that direction. As well, many accidents involving helicopters are the result of people going to the rear of the helicopter and being struck by the tail rotor. It's much smaller in diameter, operates in the vertical plane, but just as invisible to the unsuspecting...
Tellboy is right. When I served in the Army, we were trained to keep our heads low when boarding or leaving a helicopter because of the possibilty of a blade dipping.