A Hawaiian Airlines pilot said a cloud “came up” like a plume of smoke just before the plane experienced severe turbulence that injured 25 people last month, according to a preliminary report from federal investigators.
The National Transportation Safety Board said in the report that the flight’s captain reported conditions were “slippery and with clear skies.”
Then “within seconds a cloud shot up vertically (like a plume of smoke) in front of the plane, and there wasn’t enough time to deviate,” the report said.
The captain warned the chief flight attendant that the flight could experience turbulence and within one to three seconds the plane encountered severe turbulence, the report said, citing the captain’s account.
“Shortly after the turbulence-related disturbance, the chief flight attendant informed the flight crew that there were multiple injuries in the cabin,” the report said. It added that an examination of the weather in the area after the accident “revealed that there was a closed frontal system with an associated top-floor trough” moving towards the Hawaiian Islands.
The turbulence injured 25 people — six of them seriously — on the Dec. 18 flight from Phoenix to Hawaii with 281 passengers and 10 crew members, according to the report. Earlier, officials said three dozen people were injured, 11 of them seriously, and there were 238 passengers on board.
The turbulence hit about 40 minutes before the flight was due to land at Honolulu International Airport. The aircraft sustained minor damage, although the report gave no details.
Investigators said satellite and weather radars, along with lightning data, showed there were “strong cells” in the area and the National Weather Service had issued a thunderstorm warning. There were no previous reports of severe turbulence before the incident, the report said.
The NTSB will continue the investigation and issue a final report, usually within 12 to 24 months, the agency said.
Turbulence, air movement that often occurs unexpectedly and cannot be seen, can be caused by a variety of conditions, including cold or warm weather fronts, thunderstorms, and jet streams.
Between 2009 and 2021, at least 146 people, including passengers and crew, were seriously injured by turbulence, according to Federal Aviation Administration data.