Justapax1 Not been down the back end of a 74 for over 20 years. But I do recall that the 340-600 did a steady rocking in the cruise. Sitting in the PE cabin was directly over the wing and - looking out of the window at the stars - you could see the wing moving steadily up and down. Inside the cabin, not looking out of the window - it could not be sensed. I have no idea how much the wing was moving as it was night time and the wing is very long!