MD-11
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action
Weather
In cruise at FL360; encountered severe turbulence. Autopilot disconnected and I took control of the aircraft manually. Main focus was trying to keep the wings level. Airplane climbed 1500 feet to FL370. Had intermittent stick shaker while trying to keep the wings level. Can't really say how long the event lasted. Probably several minutes. After exiting the severe turbulence we descended back to FL360 and notified ATC of the encounter and altitude deviation. Then continued to our destination. Our route of flight was planned through an area forecasted for moderate turbulence. It turned out to be severe. We weren't painting any weather on the radar. Prior to the severe turbulence encounter we were experiencing light to moderate turbulence. We asked ATC for ride reports but they had none. We had descended from FL 340 to FL300 but that didn't help. Then climbed to FL320 with still no relief. Looked like we could possibly get in the clear at higher altitude so we tried FL360 which is where we encountered the severe turbulence. Don't file a route that has moderate turbulence forecasted on it. Take a longer/different route.
I was asleep in the back for my crew rest period; I woke up to some turbulence which got worse and worse. When it was safe; I made my way to the cockpit and seat belted myself into the observer's seat. When I came in; the First Officer (FO) was hand flying because the autopilot had kicked off and we were in a right turn to avail some weather. Then we received a selcal from Radio and messages from [Center] via CPDLC. When I entered; we were on our assigned altitude of 36;000 ft but was told by the crew that as we passed the ZZZZZ intersection; the autopilot had kicked off and the aircraft had uncontrollably climbed to as high as 37;500 ft. Shortly after; we broke out of the clouds and it smoothed out with no further event.Undetectable turbulence. The weather radar was painting some weather (yellow); but only with the radar pointed way down. PIREPS; which we did pass along to ATC & [Dispatch]. Captain sent a message to [Dispatch] recommending a 50NM deviation north to following aircraft. Possibly flying higher but we were limited due to weight.
MD11 flight crew reported a temporary loss of control due to severe turbulence.