Often take the person of the plane to know, the meeting after the plane enters cloud layer has bumpy generation, bump to be listed by force particularly in cumulus humilis, strong rain field especially, when Dan Zaiqing flies for nothing, compare smooth. Dan Zaiqing is empty in 10 thousand lis blue sky, also meet sometimes like undercurrent hiding below Xiang Pingjing's offing, can appear now and then intense care take offense flows, make the plane produces intense jolt, namely " of jolt of " clear sky. It produces the upper air in 7000 meters of above commonly, wide about 100 kilometers, thick inside about 1000 meters limits. Although this kind of jolt is impossible to cause malign flight accident, but aircrew processing is undeserved, also can cause a passenger to be weighed, even crisis person is safe. When the plane encounters clear sky to bump, aircrew stoping takes measure to break away from bumpy area, the passenger needs to sit alertly the clew lamp that " of chair upper part is " of good safety belt, when the light is bright, fasten good safety belt in time, in case accident.