Incident Overview
An air carrier flight encountered a brief period of unexpected severe turbulence while cruising at flight level 240. The aircraft, which had been experiencing light to moderate turbulence throughout the flight, was not damaged and landed uneventfully at its destination. However, all three flight attendants who were standing at the time sustained injuries.
Sequence of Events
Prior to the incident, the captain had instructed the flight attendants to secure the cabin earlier than usual due to the expectation that turbulence conditions would not improve before arrival. While the flight attendants were performing final preparations for landing, the aircraft suddenly experienced severe turbulence lasting 1 to 2 seconds. The weather radar showed no echoes at the time. The recorded g-forces ranged from a maximum of 1.773 g to a minimum of 0.391 g.
Injuries and Damage
All three flight attendants were standing when the turbulence occurred. They were jolted upward and subsequently fell to the floor. Two of the flight attendants sustained minor injuries, and one flight attendant suffered a serious injury. The aircraft itself was not damaged.
Conclusion
The event involved unexpected severe turbulence during a phase when flight attendants were standing and preparing the cabin. The source does not provide a specific cause for the turbulence or the injuries.