Airbus A319 N801UA

Summary

On 9 May 2011 at about 09:06 local time, a Airbus A319 registered N801UA, operated by United Airlines, Inc., was involved in an accident near Chillicothe, Missouri, United States. 125 people were on board and one was seriously injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

9 May 2011 at 09:06

Classification

Accident

Location

Chillicothe, Missouri, United States

Coordinates

39.8767, -93.6406

Aircraft

Airbus A319

Registration

N801UA

Category

Airplane

Engines

2

Operator

United Airlines, Inc.

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Phoenix → Chicago

Aircraft damage

Not recorded

Weather

VMC

Light

Night/Dark

NTSB number

DCA11FA053

1 person was seriously injured.

An inadvertent encounter with unforecast convective turbulence.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.