Narrative:

We encountered three separate instances of the stick shaker after takeoff. The first encounter occurred at 246K clean maneuvering speed in a 25 degree aob [angle of bank] right turn level at 10;000 feet. The stick shaker went on and off two times for a total of approximately 5 seconds of activation. We were maneuvering around convective activity but not encountering anymore than continuous light turbulence. The second encounter occurred at 260K at 15 degrees aob climbing again in continuous light turbulence. The third encounter occurred at 300K wings level climbing. We discussed with dispatch and maintenance control what had occurred. Maintenance control did not find any history nor did he have any suggestions as to what could have caused the stick shaker to activate. The captain discussed with the crew and dispatch what the safest options would be. The forecast weather at our destination was thunderstorms and rain showers with low ceilings. We concluded that flying over the ocean and continuing on to destination would not be the safest option because we could not determine the cause of the stick shaker. The captain elected to return to our departure airport where company maintenance would be able to address this problem. We dumped 24;000 lbs of fuel to prevent an overweight landing. There was convective activity over the airport so we elected to hold until the weather cleared and then landed uneventfully.

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Original NASA ASRS Text

Title: A B767-300 dumped fuel and returned to the departure airport following multiple instances of inappropriate activation of the stick shaker/stall warning system.

Narrative: We encountered three separate instances of the stick shaker after takeoff. The first encounter occurred at 246K clean maneuvering speed in a 25 degree AOB [Angle Of Bank] right turn level at 10;000 feet. The stick shaker went on and off two times for a total of approximately 5 seconds of activation. We were maneuvering around convective activity but not encountering anymore than continuous light turbulence. The second encounter occurred at 260K at 15 degrees AOB climbing again in continuous light turbulence. The third encounter occurred at 300K wings level climbing. We discussed with Dispatch and Maintenance Control what had occurred. Maintenance Control did not find any history nor did he have any suggestions as to what could have caused the stick shaker to activate. The Captain discussed with the Crew and Dispatch what the safest options would be. The forecast weather at our destination was thunderstorms and rain showers with low ceilings. We concluded that flying over the ocean and continuing on to destination would not be the safest option because we could not determine the cause of the stick shaker. The Captain elected to return to our departure airport where company maintenance would be able to address this problem. We dumped 24;000 lbs of fuel to prevent an overweight landing. There was convective activity over the airport so we elected to hold until the weather cleared and then landed uneventfully.

Data retrieved from NASA's ASRS site as of April 2012 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.