Pilot Debrief

BOEING 767-224 near Bavaro — 2009-08-03

Final reportDCA09IA071
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Date
2009-08-03
Location
Bavaro, DO
Aircraft
BOEING 767-224
Registration
N76156
Category
Airplane
Highest injury
Minor
Fatalities
0

Probable cause

The flight crew's inadvertent flight through the top of a convective updraft that resulted in an encounter with convective induced turbulence. Contributing to the severity of the incident was the unrestrained status of several passengers, contrary to the lighted seat belt sign.

NTSB narrative

The Captain stated that the ride had been smooth at their cruise altitude of 36,000 feet and he was able to see lights on the ground below with good forward visibility as well. The autopilot was engaged, both weather radar devices were on and functioning normally, and the seat belt sign was illuminated. Seconds after he initiated a climb to 38,000 feet, the aircraft encountered an initial severe bump followed by a few seconds of moderate turbulence and a final severe bump within the span of about ten seconds. The aircraft continued to climb and level off at 38,000 feet. The Captain was notified that there were some passenger and flight attendant injuries and made the decision to declare a medical emergency diversion to Miami International Airport in Florida where the aircraft landed one hour and forty minutes later. The FDR data indicated that, upon a climb from 36,000 feet to 38,000 feet, the vertical acceleration changed from 1.0 g’s to 2.0 g’s in one second, continued to oscillate from 2.0 g’s to 0.9’s for seven seconds before returning to 1.0 g’s and then immediately accelerating to -1.0 g’s in 0.5 seconds. No pilot reports near the location and close to the time of the turbulence encounter were found on record, and the weather document issued for the incident flight showed no predicted turbulence activity at the time of the turbulence event in the turbulence region. In addition, a meteorological study using satellite weather imagery at the time of the incident indicated the presence of isolated, rapidly developing cumulus congestus to cumulonimbus clouds under the airplane’s flight path.

NTSB coding

  • Turbulence encounter · Enroute
View NTSB final report

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