Light Transport; Low Wing; 2 Turbojet Eng
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Flight Crew Regained Aircraft Control
Weather; Environment - Non Weather Related
Encountered severe turbulence over the Sierra Nevada's at FL230. Was on RAZZR arrival into SJC. Auto pilot went off line 3 times. Hand to hand fly the rest of the arrival. Turned off the arrival towards the San Joaquin valley. Tried climbing but was limited by traffic. 230 was highest altitude available. Turbulence subsided once over the valley and away from the foothills. Gained 200 plus feet at worst.
SJC RAZRR4 arrival at FL250 slightly south of STSHH intersection we encountered severe turbulence that caused a 200 ft. loss of altitude and temporary loss of control of the aircraft. The autopilot failed and the master warning was triggered. We advised ATC with a PIREP and turned westbound to get away from the mountains. This arrival with a section that flies along the windward side of the mountains should be avoided during inclement weather. It's very likely that icing and turbulence would be worse during weather events.
Fractional flight crew reported encountering severe turbulence at FL230 over the Sierra Nevada Mountains.