Oakland International Airport
Aircraft Accident/Incident Report

Oakland, California 94502
Thursday, December 1, 2011 19:53 PST

NTSB Narrative Summary Released at Completion of Accident

The flight was transitioning through an area of known severe turbulence. One of the flight attendants reported that the flight crew asked the cabin crew to secure the cabin early as they expected to encounter turbulence during the descent. Shortly thereafter, the airplane encountered severe turbulence and the flight attendants were thrown about the galley; one sustained a serious injury. The cockpit voice recorder contained audio that was not relevant to the flight (it was likely recorded over by subsequent events), thus it could not be conclusively determined when the flight crew asked the flight attendants to be seated because they could not recall. It is likely that the flight crew’s request for the cabin to be secured was close to the time of the turbulence encounter, since none of the flight attendants had completed securing the service items when the encounter occurred. Synoptic conditions were favorable for mountain wave activity and a significant meteorological information (SIGMET) advisory and airmen’s meteorological information advisories had been issued for turbulence over the region. The flight crew also had an advisory issued from their enhanced weather information systems for severe turbulence. The event occurred in the region that the SIGMET and the advisory for severe turbulence had been issued. According to the filed flight plan, the flight was to descend before entering the advisory area for weather avoidance; however, the planned descent was not followed.

NTSB Probable Cause Narrative

The flight crew’s flight into known severe turbulence associated with mountain wave activity.

Event Information

Type of Event Accident
Event Date 12/1/2011
Event Day of the Week Thursday
Time of Event 1953
Event Time Zone Pacific Standard Time
Event City Oakland
Event State CALIFORNIA
Event Country --
Zipcode of the event site 94502
Event Date Year 2011
Event Date Month 12
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 373936N
Event Location Longitude 1192748W
Event Location Airport Oakland International Airport
Event Location Nearest Airport ID OAK
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles 120
Degrees magnetic from airport --
Airport Elevation 9
Weather Briefing Completeness --
Investigator's weather source Weather Observation Facility
Time of the weather observation 1955 Pacific Standard Time
Direction of event from weather observation facility (degrees) 93
Weather Observation Facility ID MMH
Elevation of weather observation facility 7135
Distance of event from weather observation facility (units?) 30
Time Zone of the weather observation PST
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) -6
Dew Point at event time (in degress fahrenheit) -15
Wind Direction (degrees magnetic) 270
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 6
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.15
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor 2
Injury Total None 97
Injury Total Serious 1
Injury Total All 3
Investigating Agency NTSB
NTSB Docket Number (internal use) 31750
NTSB Notification Source FAA AWP Operations Center
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Aug 6 2013 5:30PM
User who most recently changed record coos
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N261WN
NTSB Number WPR12LA053
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? Yes
Damage None
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BOEING
Aircraft Model 737-7H4
Aircraft Series Identifier --
Aircraft Serial Number 32517
Certified Max Gross Weight 154500
Aircraft Category Airplane
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats 4
Cabin Crew Seats 4
Passenger Seats 137
Total number of seats on the aircraft 145
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Nov 30 2011 12:00AM
Airframe hours since last inspection 79
Airframe Hours 18350
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name SOUTHWEST AIRLINES CO
Aircraft Owner Street Address PO BOX 36611
Aircraft Owner City DALLAS
Aircraft Owner State TX
Aircraft Owner Country USA
Aircraft Owner Zipcode 75235-1611
Operator is an individual? No
Operator Name SOUTHWEST AIRLINES CO
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address PO BOX 36611
Operator City DALLAS
Operator State TX
Operator Country USA
Operator Zip code 75235-1611
Operator Code SWAA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) --
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code ABQ
Departure City Albuquerque
Departure State NM
Departure Country USA
Departure Time 1919
Departure Time Zone MST
Destination Same as Local Flt crash at destination city
Destination Airport Code OAK
Destination City Oakland
Destination State CA
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Aug 6 2013 5:31PM
User who most recently changed record coos
Since inspection or accident Last Inspection
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --