Clear air is hideous. Once did CMB-LHR and I can easily say it was the worst flight of my life. At one point the crew were lying on the floor being held down by pax leaning over their chairs with their hands on their backs to stop them flying up. Crew were gripping the under seat struts so hard there hands were white. According to the IFE trip display we lost 1500ft at one point and I have no reason to disagree with that. Naturally all service was suspended. The worst thing is this happened for hours. I am guessing it's due to warm air thermals over the Indian Ocean? All I know is that when we got to LHR the vast majority of the cabin either hugged each other or burst into tears as they exited the aircraft. One person even kissed the ground.
We got the train back to MAN.
Having flown through that even a scewball into Chicago seems tame.