Boeing 737-724 N27722 accident near Mcallen, Texas

Probable cause

The injured passenger's failure to comply with the requirement to remain seated with a fastened seatbelt.

NTSB analysis

Before departure the captain briefed all crew members not to perform any services and remain in their jump seats for the duration of the flight due to the possibility of severe weather. The lead flight attendant then made a public address announcement to the passengers that due to possible bad weather there would be no service and the seat belt sign would remain on during the entire flight, stressing the need for the passengers to remain in their seats. In addition, the first officer made a similar announcement to the crew and passengers stressing the need to remain seated for their safety. While descending to the destination airport, a passenger who had gotten up and went into the lavatory sustained serious injuries when the airplane encountered an area of severe turbulence. In addition, two passengers and a flight attendant not wearing their seatbelts sustained minor injuries.

Text from the NTSB. Open the NTSB docket for CEN09LA256 for the full record.