Boeing 767 N584HA accident near Pago Pago, AQ

Probable cause

The airplane’s encounter with convectively-induced turbulence, which resulted in serious injury to one flight attendant.

NTSB analysis

Shortly after departure, the airplane experienced what the captain described as three or four “jolts” of moderate turbulence. The captain reported clear skies with thunderstorms in the area. The seatbelt sign was illuminated in the cabin, and the passengers were in their seat. One flight attendant, who was in the aft cabin preparing a beverage cart, sustained serious injuries. The airplane continued to climb and the remainder of the flight was uneventful. The flight data recorder recorded vertical and lateral accelerations consistent with a turbulence encounter. According to the FDR, the disturbance lasted less than 10 seconds, and there was a change in wind speed and direction evident around that time period. Although no convective activity was noted at the accident location at the accident time, satellite imagery identified convective activity in the region. The airplane was ascending near a boundary defined by a significant decrease in atmospheric moisture. This type of boundary is conducive to the propagation of gravity waves and most likely contributed to the convectively-induced turbulence that the airplane encountered.

Text from the NTSB. Open the NTSB docket for WPR11LA071 for the full record.