Incident Overview
On December 26, 2024, at 1335 Pacific Standard Time, Alaska Airlines Flight 700, a Boeing 737-9 (registration N958AK), encountered severe turbulence during cruise flight near Henderson, Nevada. The flight was operating under Title 14 Code of Federal Regulations Part 121 as a scheduled domestic passenger service from Seattle-Tacoma International Airport (SEA), Seattle, Washington, to Phoenix Sky Harbor International Airport (PHX), Phoenix, Arizona. Of the 181 passengers and crew onboard, two flight attendants sustained serious injuries and one received a minor injury.
Pre-Flight and In-Flight Precautions
According to the flight crew, turbulence experienced during the first half of the flight was described as “no worse than light chop.” The crew was aware that more significant turbulence was forecast for the second half of the flight, as indicated by weather products and advisories included in the dispatch paperwork. Additionally, they monitored a company weather application and maintained communication with dispatch for updates on weather conditions and turbulence forecasts.
Before departure, the pilots briefed the lead flight attendant regarding the timing of service and preparation for landing in light of the expected turbulence. As the aircraft neared the anticipated turbulent area while at flight level (FL) 330, the first officer made a public address announcement, advising passengers that the seatbelt sign would be activated in approximately 15 minutes and that flight attendants would then be seated. Fifteen minutes later, the aircraft encountered light turbulence, prompting the first officer to turn on the seatbelt sign and inform the flight attendants that turbulence was expected to increase and that they should secure the cabin and take their seats. The first officer contacted air traffic control (ATC) and reported light with occasional moderate turbulence. ATC advised that light chop was present throughout the Las Vegas area and that no reports of more intense turbulence had been received.
Turbulence Encounter and Injuries
Approximately 15 minutes later, the aircraft encountered severe turbulence. Two flight attendants were seriously injured, and a non-revenue flight attendant passenger sustained a minor injury. All three individuals were located in the rear galley area and were not restrained at the time of the encounter.
Post-Encounter Actions
The pilots declared a medical emergency and decided to continue to Phoenix, determining that diverting to the nearest airport would require routing through the area of expected turbulence. The remainder of the flight proceeded without further incident. Upon arrival, emergency medical services personnel met the aircraft at the gate, and four flight attendants were subsequently transported to a hospital.
Weather Data Review
A post-accident review of weather data indicated that a Significant Meteorological Information (SIGMET) advisory was issued at 1213, forecasting occasional severe turbulence between FL270 and FL400 due to wind shear associated with the jetstream in an area surrounding the accident location. A pilot report (PIREP) filed five minutes prior to the accident described similar conditions in the general vicinity. Additionally, an Airman’s Meteorological Information (AIRMET) advisory issued at 1245 forecast moderate turbulence between FL180 and FL400. Satellite and weather radar data for the accident area showed cloud cover above the turbulence location and no precipitation echoes, respectively.
Investigation
Qualified parties, including Alaska Airlines, the Federal Aviation Administration (FAA), and the National Air Traffic Controllers Association, were invited to participate in the investigation. The National Transportation Safety Board (NTSB) assigned specialists in air traffic control, meteorology, and operations to the investigation, which is ongoing.