Large Transport
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Distraction; Workload
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Ground Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Flight Crew Requested ATC Assistance / Clarification; Flight Crew Regained Aircraft Control; Flight Crew Became Reoriented
Weather; Airspace Structure
We were filed at 21;000 feet. Center required that we climb to 23;000 feet to overfly the Military Operation Area enroute. As we entered the turbulence the aircraft indicated an uncommanded descent and an increase of airspeed towards the overspeed zipper. We ended up 500 feet below our assigned altitude. We contacted Center to report our encounter and asked for a lower altitude to depart the turbulent air. They obliged and also took our PIREP regarding our turbulence encounter. Given we had lost 500 feet and could do nothing to stop this it is my opinion that we were in severe turbulence. Once on the ground; we wrote up the aircraft for inspection and then notified the [Chief Pilot].
Air Carrier Captain reported encountering severe turbulence which caused them to lose 500 feet of altitude and descend into a Military Operation Area.