A Hawaiian Airlines flight encountered severe turbulence after a “cloud rose vertically” in front of the plane on December 1. 18, resulting in injuries to 25 people, according to a preliminary report by the National Transportation Safety Board.
The independent federal agency released the report on Hawaiian Airlines Flight 35 on Friday, detailing the weather conditions at the time of the turbulence.
A Hawaiian Airlines Airbus A330 captain told investigators the plane was flying at a flight level of about 40,000 feet above a cirrostratus cloud layer. Flight conditions were smooth with clear skies and the weather radar was on when a cloud rose vertically like a plume of smoke in front of the aircraft within seconds, according to the report.
There was not enough time to change course, the captain said. He called the senior flight attendant to advise that the aircraft might be affected by turbulence. Then, within one to three seconds, the plane experienced “strong convection-induced turbulence” around 10:07 a.m.
The plane – en route to Honolulu from Phoenix – was about 65 nautical miles north-northeast of Kahului at the time and about 40 minutes from landing at Daniel K. Inouye International Airport. Honolulu.
Shortly after the sudden turbulence, the chief stewardess informed the flight crew that there were multiple injuries in the cabin. Of the 291 passengers and crew aboard the flight, 25 people were injured. Among the injured, four passengers and two crew members were seriously injured, and 17 passengers and two crew members were slightly injured. The aircraft sustained minor damage.
Investigators conducted a post-accident review of weather conditions in the area which revealed an “occluded frontal system with an associated upper-level trough moving toward the Hawaiian Islands. Satellite and weather radar imagery and lightning data have showed strong cells near the flight,” the report said.
Additionally, at the time of the incident, the United States National Weather Service had issued a major weather warning for “integrated thunderstorms with highs reaching FL 380 (flight level 38,000 feet)” above the region.
The NTSB’s preliminary report stated prior to the incident that no pilots reported severe turbulence along the route.
An NTSB spokeswoman said an investigation typically takes a year or two, when a final probable cause report is expected to be released. A Hawaiian Airlines spokesperson declined to comment on the agency’s preliminary report due to the ongoing investigation.
NTSB Preliminary Report – Flight HA 35 by Honolulu Star-Advertiser on Scribd