Incident Overview
On April 18, 2009, at 0152 central daylight time, a Boeing 737-724, registration N27722, operated by Continental Airlines as Flight 511, encountered severe turbulence while descending for an approach to McAllen Miller International Airport (KMFE). The flight was a scheduled domestic passenger service under Title 14 CFR Part 121, originating from George Bush Intercontinental/Houston Airport (KIAH) in Houston, Texas. The flight operated under an instrument flight rules (IFR) flight plan during night instrument conditions. There were 109 people on board: 2 flight crew, 3 flight attendants, and 104 passengers. The airplane landed at KMFE at 0216 and arrived at the gate at 0220.
Precautionary Briefings and Flight Details
The captain briefed all crew members to remain in their jump seats and not perform any services due to the possibility of severe weather. The lead flight attendant made a public address announcement to passengers about the lack of service and the importance of remaining seated with the seat belt sign illuminated. The flight took off from Houston approximately three hours later than scheduled and climbed to 38,000 feet. En route, the pilot circumnavigated thunderstorm cells. The first officer also made announcements stressing the need for passengers to remain seated. A total of four or five announcements were made as several passengers attempted to use lavatories. The seat belt sign was illuminated for the entire flight.
Turbulence Encounter and Injuries
The descent began with the airplane at an airspeed of 280 knots and a descent rate of approximately 1,000 feet per minute. Weather radar indicated a line of precipitation about 5 to 10 nautical miles wide, depicted in green from -2 to +2 degrees. The airplane entered a cloud formation at about 20,000 feet mean sea level and encountered severe turbulence for about 15 seconds, including up and down drafts and a roll of about 30 degrees. During the turbulence, a passenger who had left their seat and entered the lavatory sustained serious injuries. Additionally, two passengers and a flight attendant who were not wearing their seatbelts sustained minor injuries.
Post-Event Actions
The descent continued to 10,000 feet as cleared. The lead flight attendant informed the captain of injuries in the aft cabin. The captain continued the approach and coordinated with Air Traffic Control to land as quickly as possible due to a medical emergency. The flight data recorder was removed for analysis. The airplane was inspected per Continental and Boeing maintenance manuals; no damage was noted, and the airplane was released for further flight.