B737 first officer reports encountering severe turbulence at FL350 resulting in both overspeed and u...

Narrative:

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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1165660
Time
Date	201404
Local Time Of Day	0601-1200
Place
Locale Reference	ZOA.ARTCC
State Reference	CA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Person 1
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 10000 Flight Crew Type 4500
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Speed All Types Inflight Event / Encounter Loss Of Aircraft Control Inflight Event / Encounter Weather / 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.