One heck of a ride
"The United Parcel Service Boeing 767-300F, registration N322UP, was operating as UPS238 at FL310 on a cargo flight from London Stansted to Louisville International. The aircraft encountered severe turbulence for about 7 minutes over eastern Greenland, having difficulty maintaining altitude, airspeed and directional control. The autopilot and auto throttles were disengaged several times before the flight was re-cleared to FL340. The aircraft landed safely at destination and company maintenance complied with Boeing turbulence inspection requirements."
7 minutes of severe turbulence is a long time.