I was reading about some inflight upset incidents, some of them with several passengers seriously injured, and there are some things in common ( almost ) in all of the cases : planes flying at cruise ( usually FL 330 or higher ), clear skies with no evidence of any atmospheric disturbance, and sudden "impact" of the plane with severe turbulence in clear air, prompting the undesirable consequence of people being hurt. I personally NEVER unlock my seat belt, but is understandable that, in long flights, with the seat belt sign off, many people think is totally safe ( and even healthy ) to take a walk in the aisle, or go to the bathroom, or to change the dipper of the baby... and then you find your self smashed into the roof of the cabin...
Can anyone explain how the CAT occurs ?
Are more common in some places ( like in the vicinity of high mountains for example ) ? Why ?
Thanks in advance !!