Date: 201512
Local time of day: 1201-1800
Location: ZFW.ARTCC, TX
Flight conditions: IMC
Weather elements / visibility: Thunderstorm; Turbulence
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Cruise
Airspace: Class A ZFW
ATC / advisory: Center ZFW
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Training / Qualification
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Weather
Primary problem: Weather

Narrative: We were assigned FL360 on the flight to DFW. While in cruise; we were working our way around a line of ThunderStorm (TS). I was pilot flying and we deviated south to avoid two large cells. After deviating south; we were told to proceed direct CLEWS on the KLNDR2 RNAV arrival. We were beginning to turn back toward CLEWS when we thought we were clear of the weather. ATC confirmed this by instructing us that we should be able to turn back toward the intersection in about 2 minutes. As we came around the corner; we encountered a large buildup/cell that was not painting on our radar due to the shadow from the first storm and also was not reported by ATC when we were advised that our route looked clear. By the time we were able to clearly see it; there was no way to avoid it. I pulled the thrust back to idle in order to slow the aircraft below Turbulent Air penetration speed in a short distance; since we didn't have much room. As we got into the cell; we began getting large airspeed fluctuations; one of which resulted in the airspeed dropping very rapidly to about 180 KIAS. As the speed unwound; the Captain called it as I was already reaching for the thrust levers. I pushed them up to the detent; but by the time the engines started to spool; the Pitch Limit Indicator came down and the shaker activated for a brief moment prior to the airspeed starting to recover. The autopilot disconnected; and I pushed the nose down slightly to avoid the shaker/pusher and to help rebuild airspeed. It appeared to be a large downdraft that caused the speed to unwind that quickly. The speed was still hesitant to increase; so I pushed the thrust past the detent into TO-1. Once the speed started to stabilize; we brought the nose back up to a level pitch and recovered our altitude. We were somewhere between 350 and 355 when I saw the altitude reverse into a climb. ATC queried us and we notified them that we lost about 500 feet due to the turbulence and were recovering back to FL360.The stick shaker as a result of not adequately reacting to the airspeed loss caused a UAS in the stick shaker activation with moderate to severe turbulence.My experience level with flying through buildups at such high altitudes was also a factor as it took me a moment longer to process it than it should have; and that resulted in activation of the stick shaker. I also allowed the airspeed to build up slightly higher than may have been necessary due to my uncertainty about whether or not airspeed was sufficient to fully recover. I erred on the side of building up more airspeed as opposed to less.Be more cautious with airspeed deviations in the event you are not able to avoid a TS cell.




Synopsis: EMB-145LR First Officer reported receiving a stick shaker after inadvertently entering a thunderstorm at FL360.