The alarming sight of a passenger jet on its roof on a runway isn’t as surprising to aviation specialists as it is to a gawking public. They can explain the flip.

“The right wing of the airplane departed the airplane and that departure meant that the left wing was still creating lift, and that’s what causes the airplane to roll on its back. That’s the physics of it,” said John Cox, a former airline pilot who is now an aviation safety specialist and chief executive officer with Safety Operating Systems, a Washington, D.C.,-based aviation safety company.