On 29 April 2014, an Embraer E170 being operated in accordance with ATC instructions in smooth air conditions suddenly encountered an unexpected short period of severe turbulence which led both members of the cabin crew to fall and sustain injury, one a serious injury. The Investigation concluded that the turbulence encountered, which had occurred soon after the aircraft began descent from FL110, was due to an encounter with the descending wake vortex of a preceding Airbus A340 which had been approximately 10 nm and 2 minutes ahead on the same track and had remained level at FL 110.