FlarePath

What happened

NTSB summary, verbatim

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.

Photographs

1the aircraft, and what the investigators found

The aircraft before the accident

Probable cause

the Board's determination

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

Occurrence sequence

1 stepsNTSB coding · CICTT taxonomy

1 · Initial climb
Turbulence encounter
defining event

Findings

1 causal · 0 contributing

CAUSE
Environmental issues › Conditions/weather/phenomena › Turbulence › Convective turbulence — Contributed to outcome

Sequence of events

9 timed eventsfrom the FDR factual report · claude-sonnet-5

10:34 UTCTakeoffp.3
Aircraft took off
~10:38 UTCClimbp.3
Autopilot was engaged about 4 minutes after takeoff during climbout
~10:42 UTCClimbp.3
Approximately 8 minutes after takeoff, as the aircraft was about to pass through 19000 feet, the aircraft experienced perturbations in the acceleration parameters
~10:42 UTCClimbp.3
The vertical acceleration parameter increased to +1.59 g's and within 2 seconds decreased to +.66 g's
~10:42 UTCClimbp.3
Vertical acceleration increased again to record a maximum value of +1.75 g's and then decreased to record a minimum value of +.05 g's 2 seconds later
~10:42 UTCClimbp.3
The lateral acceleration parameter registered a minimum of -.16 g's and a maximum of +.14 g's over the same period
~10:42 UTCClimbp.3
The disturbance lasted less than 10 seconds and there was a change in wind speed and direction evident around that time period
post-disturbanceClimb/Cruisep.3
The aircraft continued to climb and the remainder of the flight was uneventful
15:34 UTCLandingp.3
The aircraft landed

NTSB analysis

from the final report

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.

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