A Hawaiian Airlines pilot said that a cloud “shot up” like a smoke plume just before the airplane experienced severe turbulence that injured 25 people last month, in response to a preliminary report by federal investigators.
The National Transportation Safety Board said within the report that the captain of the flight reported that conditions were “smooth with clear skies.”
Then, “a cloud shot up vertically (like a smoke plume) in front of the airplane in a matter of seconds, and there was not enough time to deviate,” the report said.
The captain alerted the lead flight attendant that the flight might experience turbulence and inside one to a few seconds the airplane encountered severe turbulence, the report said, citing the captain’s account.
“Shortly after the turbulence-related upset, the lead flight attendant informed the flight crew that there have been multiple injuries within the cabin,” the report said. It added that a post-accident examination of the weather in the realm “revealed that there was an occluded frontal system with an associated upper-level trough” moving toward the Hawaiian Islands.
The turbulence left 25 people injured — six of them seriously — on the Dec. 18 flight from Phoenix to Hawaii that had 281 passengers and 10 crew members, in response to the report. Previously, officials said that three dozen people were injured, 11 of them seriously, and that there have been 238 passengers aboard.
The turbulence struck about 40 minutes before the flight was scheduled to land at Honolulu International Airport. The plane sustained minor damage, though the report didn’t provide details.
Investigators said that satellite and weather radars, together with lightning data, showed that “strong cells” were in the realm and that the National Weather Service had issued a warning for thunderstorms. There have been no previous reports of severe turbulence before the incident, the report said.
The N.T.S.B. will proceed to research and issue a final report, normally inside 12 to 24 months, in response to the agency.
Turbulence, which is air movement that usually occurs unexpectedly and can’t be seen, will be created by various conditions, including cold or warm weather fronts, thunderstorms and jet streams.
Between 2009 and 2021, not less than 146 people, including passengers and crew members, were seriously injured by turbulence, in response to Federal Aviation Administration data.