B737 Undifferentiated or Other Model
Flight Crew Last 90 Days 150; Flight Crew Total 10000; Flight Crew Type 4500
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Flight Crew Regained Aircraft Control; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Weather
The Captain was the pilot flying for the leg and we were given direct to FAPIS waypoint at FL350. Around the FAPIS waypoint while in VMC; we encountered Moderate to Severe turbulence. The turbulence caused the overspeed clacker momentarily and then we got the stall warning shaker. The Captain went into CWS to help control the aircraft. At that point we initiated an immediate descent to try and recover from the low airspeed stall condition. I immediately told ATC we were descending and were requesting lower immediately. During our descent; we continued to receive a stall shaker intermittently. It was around FL290 where we were finally able to regain control of the aircraft. After the event was over; we ended up requesting a block altitude of FL270-FL310. Even with the cruise page showing that we were 1;000 FT under max altitude; we still found ourselves in this situation due to the clear air turbulence.
B737 First Officer reports encountering severe turbulence at FL350 resulting in both overspeed and underspeed conditions. The Captain initiates a descent to regain airspeed and is not completely successful until reaching FL290.