CHI97LA060

TWA Flight 374 encountered severe clear air turbulence over Cape Girardeau at FL220 during their initial descent into St. Louis. One flight attendant received a broken clavicle and another flight attendant received bruised ribs as a result of the turbulence. The flight data recorder data showed changes in vertical acceleration between +2.5g's and -0.79g's. A SIGMET for moderate occasional severe turbulence from FL240 to FL350 was issued just after the flight took off from New Orleans, LA. TWA 374 had just been cleared to a lower altitude as it was starting to get 'bumpy' when the severe turbulence was encountered.

History of flight

On January 28, 1997, at 0853 central standard time (cst), a McDonnell Douglas DC-9-51, N414EA, operated by Trans World Airlines (TWA) as Flight 374, experienced severe clear air turbulence over Cape Girardeau, Missouri, during the initial descent into Lambert International Airport, St. Louis, Missouri. One flight attendant (F/A) was seriously injured, a second flight attendant received minor injuries. The captain, first officer, a third flight attendant, and 107 passengers on board were not injured. The airplane was not damaged. The flight originated from New Orleans, Louisiana, at 0751 cst.

The First Officer, who was flying the airplane, reported that they were informed to expect FL240 over Cape Girardeau instead of the usual FL280 because it was "bumpy." He stated the seat belt sign was turned on during the descent to FL240. He reported they were then cleared down to FL230. He stated the ride was smooth at FL230 so the seat belt sign was turned off. He reported that after a few minutes they encountered turbulence at which time they turned the seat belt sign back on and made a PA announcement for the passengers to be seated. He stated that it was at this time that the severe turbulence was encountered. The flight crew notified the Kansas City (MKC) Air Route Traffic Control Center (ARTCC) of the turbulence and requested a lower altitude. The Captain reported they checked with the flight attendants to see if anyone was injured. They were informed that one passenger and two flight attendants had sustained injuries. An emergency was declared and Flight 374 was cleared to the St. Louis Lambert International Airport.

The Captain reported that the turbulence encountered was "intense and the duration was approximately 30 seconds." He reported that they had no warning prior to the encounter and they were in clear air.

Injury information

Two of the three flight attendants on board the airplane received injuries. Flight attendant L1 received bruised ribs. Flight attendant C1 received a broken left clavicle, fractured left ribs, strained neck muscles, and bruising.

Flight attendant L1 reported she was finishing up service when the seat belt sign came on. A passenger came out of the lavatory and it became "moderately turbulent." She reported that the seats were full so she had the passenger get down on the floor and she held on to the passenger. She reported the turbulence quit at which time she and the passenger got up. On the way to the passengers seat she heard someone say "sit down." She reported they once again experienced turbulence and she pushed the passenger onto the floor and yelled for other passengers to hold her down. She stated that she "Flew up and hit the ceiling. I came down and hit my face on the seat, then flew back up and hit the ceiling and came down on the back of a seat with my left side." She reported she landed on the floor in between a row of seats. She reported she got up, checked on the passenger she pushed to the floor and took her back to her seat. She then walked through the cabin checking on passengers and saw the C1 flight attendant on the floor in the back galley. She reported he was complaining of shoulder pain. She made another seat belt PA announcement, called the cockpit, got in her jumpseat, and aided the C1 flight attendant. When she was told it was ok to get up, she walked through the cabin to check on passengers, and went to the cockpit to brief the flight crew.

The R1 flight attendant who was in the rear galley reported the seat belt sign was off when one passenger got up to use the lavatory and another got up to look at the magazine rack. He reported the passenger came out of the lavatory and "gentle turbulence" was experienced. He reported the L1 flight attendant held onto the passenger and had her get on the floor. He reported he had the passenger at the magazine rack sit down and secure his seat belt. He reported that the seat belt sign came on and he made a PA announcement for everyone to check and fasten their seat belts. He reported that the turbulence stopped for about a minute. The L1 flight attendant walked the passenger back toward her seat and he went about his duties in the rear galley. He reported, "Then it hit, I went flying to the ceiling, down to the floor on my left side at which time I heard something snap in my shoulder area. ... Then I went up in the air again, hit the ceiling and came down again on my left side." He reported he was lying on the floor when the turbulence stopped and the L1 flight attendant came back and got in her jumpseat. He reported he got up into his jumpseat but was unable to put his restraint on because of the shoulder pain. He reported he felt sick and he told the L1 flight attendant that he had to get back on the floor before he passed out. He reported he got on his knees and crawled to get behind row 24-D/E where he laid down and stayed for the remainder of the flight being aided by the other flight attendants.

The R1 flight attendant, who was not injured, reported he was in the front galley when they hit some "un-expected turbulence" which he described as "very severe." He continued to report, "It lasted about 5 to 10 seconds and stopped. My feet left the floor as I tried to brace myself. A few seconds later we hit very severe turbulence again. This time it lasted a little bit longer and was a little more intense. My feet left the ground again and I hit my head on the ceiling." He reported he got to his jumpseat and after a few minutes received a call from the L1 flight attendant telling him they would assist the passengers once it was safe to get up. The L1 flight attendant also informed him of the injured C1 flight attendant. He reported that once it was safe he went to the back of the airplane and aided the C1 flight attendant.

Meteorological information

At 0755 cdt (1355z), SIGMET Victor 2 was issued which was valid until 1155 cdt (1755Z). The SIGMET was for portions of Missouri, Illinois, Indiana, Kentucky, Ohio, Pennsylvania, and West Virginia. The area listed in the SIGMET was from Erie, PA; to Slate Run, PA; to Johnstown, PA; to London, KY; to Walnut Ridge, AR; to Springfield, MO; to Ft. Wayne, IN; to Erie, PA. The SIGMET called for moderate occasional severe turbulence between FL240 and FL350 due to windshear involving upper level jetstream. These conditions were reported by a number of aircraft. Conditions were expected to continue beyond 1155 cdt.

At 0930 cdt (1530z), SIGMET Victor 3 was issued for the same area as Victor 2 with the altitude being changed to between FL210 and FL350. This SIGMET contained the comment that injuries were reported by a DC-9 at FL210-FL220, 50 southeast of Farmington, MO. Conditions were expected to continue beyond 1330 cdt.

Numerous PIREPs were received by Air Traffic Control regarding moderate to severe turbulence over Springfield, MO; Evansville, IN; St. Louis, MO; and throughout Southern Illinois, both prior to and around the time of this incident. (See attached PIREPs)

Communications

TWA 374 was in contact with the MKC ARTCC, Sector 54 radar position controller when the turbulence was encountered. The TWA flight crew checked in with the controller at 0849:37 as being level at FL230. At 0852:41, TWA 374 reported "...its real bumpy here can we have lower please." At 0853:03, the controller cleared the flight to descend and maintain FL130 and to expedite the descent through FL210. TWA 374 acknowledged the clearance.

At 0853:36, TWA 374 reported "Kansas City we just encountered uh severe turbulence and uh we're descending now through flight level two two zero for one three thousand." At 0854:25, the controller advised TWA 602, which was about two minutes behind TWA 374, of the severe turbulence. At 0855:20, after several inquiries regarding the turbulence from other aircraft in the area, the controller m