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| Date: | Tuesday 25 December 2007 |
| Time: | 10:18 LT |
| Type: |  McDonnell Douglas MD-83 |
| Owner/operator: | Alaska Airlines |
| Registration: | N943AS |
| MSN: | 53018/1779 |
| Year of manufacture: | 1990 |
| Total airframe hrs: | 55606 hours |
| Engine model: | P&W JT8D |
| Fatalities: | Fatalities: 0 / Occupants: 114 |
| Other fatalities: | 0 |
| Aircraft damage: | None |
| Category: | Accident |
| Location: | Ontario, CA -
 United States of America
|
| Phase: | Unknown |
| Nature: | Passenger - Scheduled |
| Departure airport: | Seattle/Tacoma International Airport, WA (SEA/KSEA) |
| Ontario International Airport, CA (ONT/KONT) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
Two flight attendants were seriously injured when the airplane encountered severe turbulence while descending for landing. The turbulence was likely the result of strong easterly winds interacting with the rough terrain in the area (mechanical turbulence). The flight data recorder data indicates that the airplane experienced a vertical acceleration of 0.4 G to 1.9 G, or 1.5 G total change, which corresponds to severe turbulence. The National Weather Service forecast the severe turbulence in Significant Meteorological Advisory (SIGMET) Victor 2, which was issued before the flight departed. The weather company that provides weather information to the operator did not forecast severe turbulence for the area. The content of SIGMET Victor 2 was available to the flight's dispatcher. However, this information was not provided to the flight crew. The two flight attendants who sustained injuries were both standing, completing final cabin duties in preparation for landing, and were knocked to the floor during the turbulence encounter.
Probable Cause: The lack of turbulence forecasts available to the flight crew, which resulted in the flight attendants not being seated when the flight encountered severe terrain-induced turbulence. Contributing to the accident were the terrain-induced turbulence, the failure of the company that provided the flight's weather briefing to forecast severe turbulence, and the failure of the dispatcher to provide the National Weather Service severe turbulence forecast to the flight.
Accident investigation:
 |
|
Sources:
NTSB SEA08LA050
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 25-Mar-2024 08:29 | ASN Update Bot | Added |
| 17-Oct-2024 17:23 | ASN | Updated [Cn, Other fatalities, Narrative, ] |
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