Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Chillicothe, Missouri 64601
Monday, May 9, 2011 4:06 CDT
NTSB Narrative Summary Released at Completion of Accident
No adverse weather was forecast for the route. The seatbelt sign was turned off at FL320. The airplane leveled off at a final cruise altitude of 37,000' and the ride was smooth up until the turbulence encounter. Both the captain's and first officer's weather radar was in use before and during the turbulence event, and there was no adverse weather along the route visible on radar. The flight crew received no weather updates from Air Traffic Control, no pilot reports (PIREPS), and there was no traffic along the same route in front of this flight.
Evaluation of the winds using FDR data revealed that the aircraft sustained strong and adverse wind fluctuations on all three axes during the turbulence encounter, which included an upwards vertical wind gradient was about 80 knots in a 10 second timeframe. Recorded ground weather radar information revealed that the flight was probably passing over or through the extreme top of a rapidly developing area of convective weather at the time of the turbulence encounter. Although ground based radar reflectivity data indicated that the precipitation rate within this rapidly developing cell at the time was light to moderate, detection of the cell would likely have required active adjustment of the aircraft's weather radar system. However, the flight crew was not actively manipulating the aircraft radar at the time of the event given the lack of severe weather indications.
NTSB Probable Cause Narrative
An inadvertent encounter with unforecast convective turbulence.
Event Information
| Type of Event | Accident |
| Event Date | 5/9/2011 |
| Event Day of the Week | Monday |
| Time of Event | 406 |
| Event Time Zone | Central Daylight Time |
| Event City | Chillicothe |
| Event State | MISSOURI |
| Event Country | -- |
| Zipcode of the event site | 64601 |
| Event Date Year | 2011 |
| Event Date Month | 5 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 395236N |
| Event Location Longitude | 0933826W |
| Event Location Airport | -- |
| Event Location Nearest Airport ID | -- |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Unknown |
| Time of the weather observation | |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | -- |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | -- |
| Lighting Conditions | Night/Dark |
| 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) | -- |
| Air Temperature at event time (in degrees celsius) | -- |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | -- |
| Wind Speed (knots) | -- |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | -- |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | -- |
| 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 | -- |
| Injury Total None | 124 |
| Injury Total Serious | 1 |
| Injury Total All | 1 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | -- |
| NTSB Notification Source | Federal Aviation Administratio |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | May 28 2013 9:10PM |
| User who most recently changed record | schd |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N801UA |
| NTSB Number | DCA11FA053 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | Unknown |
| Flight plan Was Activated? | Yes |
| Damage | None |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | AIRBUS |
| Aircraft Model | A319 |
| Aircraft Series Identifier | 131 |
| Aircraft Serial Number | 686 |
| Certified Max Gross Weight | 166400 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 2 |
| Cabin Crew Seats | 4 |
| Passenger Seats | 120 |
| Total number of seats on the aircraft | 126 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | May 6 2011 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 47316 |
| ELT Installed | Unknown |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | United Airlines, Inc. |
| Aircraft Owner Street Address | 77 West Wacker Drive |
| Aircraft Owner City | Chicago |
| Aircraft Owner State | IL |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 60666 |
| Operator is an individual? | No |
| Operator Name | United Airlines, Inc. |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | 77 West Wacker Drive |
| Operator City | Chicago |
| Operator State | IL |
| Operator Country | USA |
| Operator Zip code | 60666 |
| Operator Code | UALA |
| 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 | UALA011A |
| 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 | PHX |
| Departure City | Phoenix |
| Departure State | AZ |
| Departure Country | USA |
| Departure Time | 2351 |
| Departure Time Zone | PST |
| Destination Same as Local Flt | -- |
| Destination Airport Code | ORD |
| Destination City | Chicago |
| Destination State | IL |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | May 18 2011 7:54AM |
| User who most recently changed record | benr |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |