Aviation Accident Summaries

Aviation Accident Summary FTW03LA121

Palestine, TX, USA

Aircraft #1

N71411

Boeing 737-924

Analysis

The transport category airplane encountered severe turbulence while deviating around weather at flight level 280 (FL280). The captain had informed the flight attendants to leave the carts stowed and sit down because they might get "a few bumps" for the next minutes or so. The "Fasten Seat Belt" sign was illuminated, and had not been turned off since takeoff. A few minutes later the airplane encountered "moderate turbulence" with no preceding chop. One flight attendant, who was in the aft galley was trying to stow away the beverage cart after receiving a call reporting turbulence the airplane may encounter. While trying to stow the cart away, the cart rolled into her right side, resulting in a fractured femur. Following the turbulence encounter, the airplane diverted to another airport and landed without further incident.

Factual Information

On April 6, 2003, at 1055 central daylight time, a Boeing 737-924 transport category airplane, N71411, operating as Continental Airlines Flight 111, was undamaged after an encounter with severe turbulence during cruise flight near Palestine, Texas. The airplane was registered to, and operated by Continental Airlines, Inc., of Houston, Texas. The captain, first officer, 4 flight attendants and 83 passengers were not injured; however, one flight attendant sustained serious injuries. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan was filed for the 14 Code of Federal Regulations Part 121 scheduled passenger flight. The domestic cross-country flight originated from the George Bush Intercontinental Airport, near Houston, Texas, at 1032, and was destined for the Salt Lake City International Airport (SLC), near Salt Lake City, Utah. According to the captain, during cruise flight at flight level (FL) 280 and deviating around weather, the airplane encountered severe turbulence near the RIKKS intersection. RIKKS is located at the intersection of the 083 degree radial from the Leona Vortac and the 339 degree radial from the Waco Vortac. Prior to the encounter with turbulence, the captain had instructed the flight attendants to leave the carts stowed and sit down due to the possibility of encountering "a few bumps" for the next few minutes. The "Fasten Seat Belt" sign was illuminated, and had not been turned off since takeoff. A few minutes after the captain issued the instructions, the airplane encountered "moderate turbulence" with no preceding chop. One flight attendant, who was in the aft galley trying to stow away the beverage cart when the turbulence was encountered was injured by the cart. She reported that the cart rolled into her right side, resulting in a fractured femur. Flight 111 diverted to the Dallas Fort Worth International Airport (DFW), near Dallas-Fort Worth, Texas, and landed without further incident. According to the Flight Data Recorder (FDR) factual report indicated that turbulence was encountered at an altitude of approximately 28,000 feet mean sea level and a magnetic heading of approximately 332 degrees. According to the data, the autopilot went from the engaged mode to the off-mode approximately 8 seconds after the turbulence upset and was turned back on about 40 seconds later. The severe turbulence encounter lasted for 14 seconds. During the turbulence, the vertical acceleration parameter recorded a maximum of +2.16 g's and a minimum of 0.00 g's. The lateral acceleration parameter recorded a maximum of +0.18 g's and a minimum of -0.18 g's. The longitudinal acceleration parameter recorded a maximum of +0.08 g's and a minimum of -0.03 g's. The aircraft entered the turbulence in a right roll of approximately +14 degrees. During the turbulence the roll changes to -7.7 degrees and then goes back to +4.4 degrees. At the moment the autopilot parameter reengages, the aircraft has a roll attitude of 0 degrees. The aircraft's pitch at the beginning of the turbulence is 2.1 degrees.

Probable Cause and Findings

The airplane's encounter with unforecasted clear air turbulence during cruise flight.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports