History of Flight
On December 18, 2022, about 1007 Hawaii standard time, Hawaiian Airlines flight 35, an Airbus A330-200 (registration N393HA), was operating at flight level 400 approximately 65 nautical miles north-northeast of Kahului, Hawaii, when the airplane encountered severe turbulence. The flight was a regularly scheduled domestic passenger operation under 14 CFR Part 121 from Phoenix Sky Harbor International Airport, Phoenix, Arizona, to Daniel K. Inouye International Airport, Honolulu, Hawaii. Onboard were 2 flight crewmembers, 8 flight attendants, and 283 passengers (including 2 off-duty Hawaiian Airlines pilots in cockpit jumpseats and 3 lap-held children). Four occupants (1 flight attendant and 3 passengers) sustained serious injuries, and 20 occupants (3 flight attendants and 17 passengers) sustained minor injuries. The airplane sustained minor damage.
The captain was the pilot monitoring, and the first officer was the pilot flying. The captain reported that the airplane was in visual meteorological conditions at FL400 above a cloud layer between FL370 and FL380. Flight conditions were smooth with clear skies, and the onboard weather radar displayed no returns. At 0955:57, air traffic control advised the crew of another airplane that went around weather due to reported turbulence; another Hawaiian Airlines flight reported continuous moderate chop. At 1000:43, ATC advised of moderate to extreme precipitation and turbulence for the next 40 miles. About 31 seconds later, ATC noted cloud tops at FL410 with light chop and moderate turbulence.
The captain observed a cloud that appeared like a "plume" vertically ahead. The weather radar was set to elevation mode but showed nothing. At 1007:07, a crewmember said, "it's moving fast" and that the airplane should "clear most of it." About 15 seconds later, they alerted the lead flight attendant to expect a bumpy ride. At 1007:31, they noted "it's building fast." At 1007:43, the cockpit voice recorder captured sounds consistent with turbulence, autopilot disconnection, and EICAS chimes. The crew reacted with surprise, took manual control, and reengaged the autopilot. Altitude alerts sounded at 1007:43 and 1007:59.
Quick access recorder data showed that at 1007:42, the airplane's altitude increased by 68 feet to 40,088 ft with vertical acceleration of 0.69 G. At 1007:43, altitude increased by 248 feet to 40,336 ft with 1.27 G. At 1007:44 (autopilot disconnect), vertical acceleration was 2.18 G; one second later, the master caution and master warning activated. At 1007:46, vertical acceleration decreased to -0.98 G.
At 1008:12, a flight attendant announced for passengers to be seated and fasten seatbelts. Between 1008:14 and 1009:11, additional EICAS chimes were recorded. At 1008:54, the lead flight attendant notified the crew that medical assistance would be needed upon landing. At 1010:06, the crew stated they should have "gone around it." They communicated with a flight attendant who confirmed injuries in the cabin and noted cabin interior damage. At 1010:41, the crew discussed that they thought the airplane would clear the cloud formation but it "came up real fast." One questioned, "did it just pop up?" At 1013:43, a passenger announcement was made about the turbulence. The crew contacted dispatch, stating they hit 40 degrees of bank and passengers were injured. They requested medical assistance and estimated arrival at 1045.
At 1018:14, the crew informed ATC of severe turbulence at FL400 and requested expedited handling. ATC declared an emergency. At 1019:08, a flight attendant reported ceiling damage and dropped oxygen masks in the aft cabin. At 1020:52, the crew informed dispatch of three confirmed injuries and that they were "coming in as fast as [it] can." Dispatch said emergency medical services were ready. At 1024:17, the captain announced the seatbelt sign would remain on after landing for emergency personnel access.
At 1025:44, discussion about alternative actions was mostly unintelligible. At 1026:35, the crew noted the cloud formation was not depicted in red on radar and "caught them completely off guard." Minutes later, a flight attendant reported about 10 injured; the crew updated dispatch. During descent, ATC vectored for an instrument landing system approach to runway 4R. At 1033:55, the crew discussed the attitude, estimating "at least 40 degrees" and that the airplane "kicked off everything." They noted they had practiced a similar upset in the simulator.
After landing at 1046:26, flight attendants announced for passengers to remain seated for medical personnel. At 1048:44, the crew discussed the event; one crewmember said it reminded him of a "volcanic explosion" and was the "most unusual attitude" he had experienced. At 1100:03, the parking checklist was run. A crewmember visually confirmed cabin structural damage. At 1100:59, they resumed discussing the clouds: "kinda flat" but "built super fast." The crew noted that all electrical systems remained on despite autopilot and autothrottle disengagement. At 1102:39, about 12 people were injured. The CVR ended at 1103:50.
Aircraft Information
The Airbus A330-200 (N393HA) was configured with 2 pilot seats, 2 cockpit observer seats, 11 flight attendant seats, and 278 passenger seats. Three passengers were lap-held children; two off-duty Hawaiian Airlines pilots occupied the cockpit observer seats.
Meteorological Information
The weather package provided to the flight crew included SIGMETs and AIRMETs. At dispatch release, a SIGMET for thunderstorms was issued, and the dispatcher briefed the captain on potential turbulence and isolated embedded cumulonimbus clouds near Honolulu. Before departure, updated weather included a SIGMET for embedded thunderstorms. At 0745, a SIGMET update indicated embedded thunderstorms with tops to FL380 moving northeast.
Weather observations from Kahului Airport (OGG) at 0954 reported light rain, broken ceiling at 2,500 ft, overcast at 6,000 ft. Pacific surface analysis showed a Kona storm system with strong westerly winds. High-level significant weather prognostic charts valid for 0800 and 1400 depicted moderate turbulence potential over the accident site between FL240 and FL420 and isolated embedded cumulonimbus clouds to FL390. Satellite imagery at 1006 showed overshooting tops of embedded cumulonimbus clouds near the turbulence location. The closest WSR-88D radar at Kamuela, Hawaii, showed echoes of 40-45 dBZ under the flight track at 1005 and 1010. SIGMET Victor 2, current through 1145, advised of embedded thunderstorms to FL380 moving northeast. An Area Forecast Discussion at 1000 noted potential for moderate-to-severe clear air turbulence behind the main showers. Among 21 pilot reports in the area, the only severe turbulence report was from the accident flight crew; seven reported light to moderate turbulence.
Wreckage and Impact Information
Turbulence caused damage throughout the cabin. A passenger service unit in row 39 fell from the overhead compartment. Ceiling panels were missing near rows 36 to 41. An overhead light in the rear galley cracked. The flight attendant handset near door L4 broke into multiple pieces. Other damage occurred to overhead bin components, light panels, and exit signs.
Survival Aspects
The eight flight attendants had received recurrent training between May and October 2022. About 45 minutes before landing, the flight crew announced the descent and illuminated the seatbelt sign. Flight attendants were finishing cabin service. The lead flight attendant was alerted to expect turbulence during descent, but the turbulence encounter occurred while she was initiating a call to the cabin crew.
Passengers described a "hard jolt" followed by a "free fall" sensation; unsecured items floated. After about 3 seconds, "two hard hits" occurred. Unrestrained occupants were thrown upward into ceilings or baggage compartments and then onto the floor. A passenger who left her seat to use the lavatory was thrown face first into the lavatory ceiling and then onto the floor; she crawled back to her seat. Flight attendant 4 hit the ceiling twice, then secured herself at L4 door. Because the handset was damaged, she unbuckled and crawled to R4 door to call for help. Flight attendant 5 ended up on the floor after violent shaking and was helped into her seat. Medically trained passengers tended to them. Flight attendants and off-duty Hawaiian Airlines crew worked to secure loose cabin panels and check on occupants. A list of seriously injured passengers was made, and call lights were turned on for identification.
After landing, emergency personnel boarded to remove the most seriously injured occupants, including flight attendant 5. Remaining passengers disembarked through the L2 door to the gate, where triage occurred. According to Hawaiian Airlines, about 25 occupants were transported via ambulances, buses, or personal vehicles to local hospitals. One lap-held child was transported by personal vehicle and later released. Other passengers sought medical treatment after returning home.