Hawaiian Airlines Flight 35 Severe Turbulence Injuries (Airbus A330) — NTSB Findings

On December 18, 2022, Hawaiian Airlines Flight 35, an Airbus A330-243 (N393HA), encountered severe turbulence while enroute to Honolulu, Hawaii. The turbulence event resulted in 4 serious injuries and 20 minor injuries among the 293 occupants, and the airplane sustained minor damage. Federal investigators examined the turbulence encounter, available weather information, and flight crew decision-making and communications leading up to the event.

Accident Summary

What Happened

About 1007 Hawaii standard time, the airplane was operating at flight level 400 about 65 nautical miles north-northeast of Kahului, Hawaii, when it encountered severe turbulence. The captain reported the airplane was in visual meteorological conditions at FL400 and above a cloud layer between FL370 and FL380, with no weather radar returns displayed. Shortly before the encounter, the crew observed a vertically developing cloud formation that they described as a “plume,” and they contacted the lead flight attendant to advise that a “bumpy” ride was expected.

Within seconds, the airplane encountered severe turbulence that produced abrupt changes in attitude and vertical acceleration. Data from the airplane’s quick access recorder showed vertical accelerations that exceeded 2 Gs during the encounter, and the cockpit voice recording captured sounds consistent with turbulence as well as autopilot disconnect and alerting chimes. After the turbulence subsided, the flight continued to Honolulu and landed without further incident.

In the cabin, the turbulence resulted in multiple injuries and interior damage. Flight attendants and passengers who were not restrained were thrown upward into the ceiling or overhead areas and then down onto the floor, and items in the cabin became airborne. Cabin crewmembers and medically trained passengers provided assistance, and flight attendants coordinated identification of injured passengers for medical personnel upon arrival.

Aircraft and Operational Context

The flight was a regularly scheduled Part 121 domestic passenger operation from Phoenix to Honolulu conducted under IFR. The aircraft was configured with 2 pilot seats, 2 cockpit observer seats, 11 flight attendant seats, and 278 passenger seats, and the passenger count included lap-held children and off-duty company pilots in observer seats. The airplane sustained minor damage, with reported cabin interior impacts including displaced passenger service units and ceiling panel damage in the aft cabin area.

The crew received dispatcher briefings before departure that included discussion of potential turbulence and potential embedded convective activity over the Hawaiian Islands. During the flight, air traffic control provided advisories to the crew about weather and turbulence ahead, and the crew was aware that thunderstorms and turbulence could occur along the route. The event occurred at high altitude where weather radar sensitivity can be reduced, and the operator’s guidance also noted limitations in radar detection for weather composed of small droplets, such as certain cloud formations.

Accident Investigation

Investigations of turbulence encounters focus on what information was available to the crew, how developing weather was assessed, what avoidance options existed, and how cockpit-to-cabin coordination occurred, as described in our overview of the NTSB investigation process. In this event, the NTSB evaluated meteorological products along the route and timing of advisories provided to the crew, quick access recorder data showing the airplane’s vertical accelerations, and flight crew statements and recorded communications about the observed “plume” and the radar presentation. The NTSB determined that the plume comprised cumulonimbus clouds with severe-to-extreme convectively induced turbulence.

The NTSB also evaluated cabin injury circumstances and in-flight response actions, including use of the seatbelt sign, flight attendant communications, and steps taken to secure the cabin for landing. The report noted that the seatbelt sign was on before the encounter, that the crew advised the lead flight attendant of anticipated turbulence shortly before it occurred, and that the turbulence began before the lead flight attendant could complete an interphone call to other cabin crewmembers. The NTSB further found the in-flight response after the encounter to be timely and effective.

The NTSB determined the probable cause of the accident was the flight crew’s decision to fly over an observed storm cell instead of deviating around it despite sufficient meteorological information indicating the potential for severe convective activity. The NTSB also addressed that storm cells at higher altitudes can present hazards and that convectively induced turbulence can occur rapidly in developing formations, even when onboard radar depiction is limited. The NTSB noted it did not travel to the scene of this accident.

Operational and Regulatory Issues

Part 121 operations rely on layered turbulence risk management, including dispatcher briefings, forecast products, SIGMETs and AIRMETs, pilot reports, and ATC advisories. In this event, the NTSB described forecast products and a SIGMET indicating embedded thunderstorms with tops to FL380 in the region, conditions consistent with convectively induced severe turbulence near the encounter location. The report also described that the crew was above a cloud layer and observed a rapidly building plume, but did not anticipate the likely severity of the formation.

The operator’s guidance discussed in the report included recommendations to plan to fly above or around areas of severe turbulence and cautions regarding storm cells at higher altitudes. The NTSB also addressed operational factors affecting injury outcomes in turbulence encounters, including the timing and method of warnings to the cabin and the elevated risk to flight attendants who are often unseated and unbelted while performing cabin duties. The report noted that, although the seatbelt sign was illuminated, a direct public-address warning from the flight deck about anticipated turbulence was not made before the encounter.

Aviation Accident Litigation

Although the NTSB’s work is safety-focused, turbulence injury events can raise civil questions about operational decision-making, risk communication, and adherence to operator guidance, and those issues are commonly evaluated in the context of aviation accident litigation. The factual record can include operational manuals and training materials, dispatch communications, cockpit and cabin procedures, and data showing the severity and timing of the encounter. Any civil evaluation should be anchored to the verified record, including the NTSB’s factual findings and the operator’s documented procedures.

In cases involving passenger and flight attendant injuries, claims analysis often turns on what information was available about convective activity and turbulence risk, what avoidance or deviation options were practicable, and how warnings were communicated and implemented in time to reduce exposure. These issues arise across many types of aviation matters, and similar categories of operational and safety questions appear in the firm’s representative aviation matters. The assessment is highly fact-specific and depends on the operational timeline and the information flow before the event.

Where disputes proceed to resolution, outcomes can depend on medical proof, causation analysis tied to cabin dynamics and restraint use, and the completeness of operational documentation. For examples of resolved outcomes in aviation matters, see the firm’s collection of selected aviation verdicts and settlements. Turbulence injuries frequently involve individualized damages and require careful linkage between the event’s dynamics and specific injuries.

Over time, broader patterns in aviation civil outcomes can be discussed in terms of event severity, injury mix, and operational context, as reflected in the firm’s discussion of aviation crash verdict trends. In this event, the NTSB’s findings centered on the decision to overfly an observed storm cell despite available meteorological information indicating convective potential, and the documented cabin injuries that resulted. Any litigation analysis should remain aligned with those verified findings rather than assumptions about turbulence that were not supported by the record.