Date: 201504
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Physiological - Other; Situational Awareness; Workload
Second reporter function: Pilot Flying; First Officer
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action; General Maintenance Action
Contributing factors: Human Factors; Weather
Primary problem: Weather

Narrative: I was Pilot Monitoring (PM). We had seen some dark areas on the Doppler for a system moving through the country over the southeastern US; and had the weather radar on.  The radar was on automatic tilt.  We were cruising at FL 390 painting nothing on the radar in smooth flight (in fact the seat belt sign was off).  Suddenly the aircraft encountered severe turbulence.  I immediately threw the seat belt sign on as the pilot flying (PF) grabbed the yoke with both hands and turned the autopilot off.  The aircraft then went 15 degrees wing down in a descent and the airspeed increased as the clacker went off.  The First Officer (FO) continued to fly the aircraft; making pitch adjustments manually and I assisted on the throttles.  The airspeed tapes 'closed in' on us quickly and soon the stick shaker went off.  The PF did a fantastic job flying out with stall recovery; but soon the clacker went off again.  In the process we lost 300 feet and I called ATC for immediate descent to FL 370; which we did.  The aircraft rolled 15 degrees to either side throughout and the PF flew very well; keeping aircraft control.  The entire episode lasted about 30 seconds and we returned to controlled flight at FL 370.  PIREP given to ATC.  I called to the back to check Flight Attendants (FA); they were startled of course but reported nothing but a very messy galley.  I had the FO make a PA; while I typed a message to Dispatch for severe turbulence.  I double-checked with FA's for how the Passengers were doing; they reported no injuries but lots of mess.  One gentleman had been in the lavatory; but no one else was standing so that worked out in our behalf.  The FA's had been thrown around but reported no injuries as well.  I then phone patched Dispatch through the Company frequency and made a voice PIREP and told them I would be doing a writeup.   The flight continued on and landed uneventfully.  Logbook writeup made and aircraft pulled out of service for inspections.   The Flight Attendants did an amazing job keeping everyone calm and cleaning up a large mess; as most Passengers had drinks spilled as well as a big galley mess.  They should be acknowledged for a job well done; especially our 'A'.  I would also like to note that we completed a series on phone 'interviews' upon landing; and were asked if we were ok to continue on.  Both of us still had a lot of adrenaline going and answered yes.  In hindsight; we should have stopped our day right there; and not even been given the option.  We had two more legs in challenging weather and made some minor mistakes we would not normally have made.  Our natural inclination is to get the job done and power through; but I don't think I would do that again.


Second narrative: I was Pilot Flying (PF) during cruise at FL 390; 0.78 Mach. We were flying in a stratus layer associated with an occluded front and had the Weather radar on. We encountered turbulence that resulted in 15-degree roll and stick-shaker activation. I disconnected the autopilot and pitched the nose down. The aircraft kept climbing due to the updraft; and we simultaneously heard and felt the stick-shaker and high speed warning. The Captain was quick to call ATC and request FL 370; and he kept the power up. I had to lose about 300 feet to remain at flying speed. The over speed was approximately eight to ten knots into the 'clacker'. After reaching FL 370; the Captain contacted ATC and issued a UUA Urgent PIREP of severe turbulence. He addressed the Flight Attendants and assessed that there were no injuries. The Customers were notified. The Captain notified Dispatch to have Maintenance meet the aircraft upon arrival. Maintenance subsequently pulled the aircraft out of service for inspection.There were no radar returns depicting thunderstorms in the flight path; and there were no PIREPS of MDT/SVR turbulence along this airway. The Captain and I did discuss our possible crossing of a cold front with MESO activity and thunderstorms; and we had the radar set appropriately. Had we remained at FL370 instead of FL390; we would have remained in the tops instead of (mostly) in the clear. I believe that the Flight Crew and Dispatch did the best with what we had to work with.


Synopsis: A B737-700 crew reported severe turbulence at FL390 which resulted in a stall recovery descent with both stick shaker and overspeed warnings. No injuries were reported but the aircraft was removed from service.