|Title:||In-flight upset due to unexpected seat movement, McDonnell Douglas MD-11, June 29, 1994 (Recommended)|
|Micro summary:||The unexpected movement of the first officer's seat by the other pilot caused the control column to be moved, the autopilot disconnected, a violent upset, and injuries to the airplane's occupants.|
|Event Time:||1994-06-29 at 0023 EDT|
|Publishing Agency:||National Transportation Safety Board (NTSB)|
|Site of event:||Caribbean, CB|
|Departure:||Miami International Airport, Miami, Florida, USA|
|Destination:||Ministro Pistarini International Airport (Ezeiza International Airport), Ezeiza, Buenos Aires Province, Argentina|
|Airplane Type(s):||McDonnell Douglas MD-11|
|Type of flight:||Revenue|
NTSB short summary:
The reserve first officer's unauthorized movement of the first officer's seat during flight which resulted in the first officer's legs being forced against the control column, pushing it forward, and disconnecting the autopilot. This resulted in the aircraft pitching down and subjecting the occupants to negative g forces, resulting in injuries.
While en route the captain went to the main cabin for a rest period and the reserve first officer took the captain's seat. A flight attendant entered the cockpit to bring a box of beverages for the flight crew. She attempted to place them on the footrest of the center observer's seat as directed by the reserve first officer. She had trouble doing this and the reserve first officer realized the first officer's seat was in the way. He reached across the cockpit and without the first officer's knowledge activated the horizontal movement switch for the first officer's seat moving it forward. The first officer's legs were crossed and contacted the control column pushing it forward. The limitations of the autopilot system were exceeded and the autopilot turned off. The aircraft responded to the forward control column input and pitched down. This resulted in injuries to passengers and crew. The first officer took manual control of the aircraft after autopilot disconnect and returned the aircraft to level flight.
NTSB factual narrative text:
HISTORY OF THE FLIGHT
On June 29, 1994, about 0023 eastern daylight time, a McDonnell-Douglas MD-11, N1752K, registered to American Airlines, Inc., operating as American Airlines flight 901, experienced altitude deviation in cruise flight over the Caribbean Sea just south of the Cuban coast, resulting in injuries to passengers and crew. The flight was a 14 CFR Part 121 scheduled international passenger flight from Miami, Florida, to Buenos Aires, Argentina. Visual meteorological conditions prevailed at the time and an instrument flight rules flight plan was filed. The airplane received minor damage. One passenger and 1 flight attendant received serious injuries, 12 passengers and 3 flight attendants received minor injuries, and 67 passengers and 10 flight attendants were not injured. The airline transport-rated captain, first officer, and reserve first officer were not injured. The flight originated at Miami, Florida, on June 28, 1994, at 2333.
The flightcrew stated the captain was in the main cabin taking a rest period. They were in cruise flight and the seatbelt sign was off. Passengers had been requested to keep their seatbelts on when seated. The reserve first officer occupied the captain's seat and the regular first officer was flying the airplane from the right seat. A flight attendant entered the cockpit with a container of beverages. The reserve first officer instructed her to place the container on the footrest of the center observer's seat.
The reserve first officer noticed the flight attendant was having trouble doing this and realized the first officers seat was in the way. The reserve first officer reached across the cockpit and activated the horizontal movement switch of the first officer's seat, without his knowledge, to move it forward out of the flight attendant's way. The first officer had his legs crossed behind the control column and as his seat was moved forward his legs pushed forward on the column. The autopilot turned off and the aircraft responded to the forward control column input and nosed down. The first officer then took the aircraft controls and returned the aircraft to level flight.
The captain returned to the cockpit and the flight attendants reported that some unrestrained passengers and flight attendants had been injured when the aircraft nosed over. The captain instructed the first officer to continue toward Kingston, Jamaica for a possible landing. The captain contacted American Airlines flight dispatch and it was determined that emergency assistance was not available in Kingston, for they could not reach anyone on the phone. The captain then elected to return to Miami, Florida, where the aircraft landed at 0205.
Information on the three flight crewmembers is contained in this report under Pilot Information, and in attachments to this report.
Information on the aircraft is contained in this report under Aircraft Information.
Visual meteorological conditions prevailed at the time of the accident. Additional meteorological information is contained in this report under Weather Information, and in attachments to this report.
The cockpit voice recorder continued to operate after the accident and recordings for the time of the accident were recorded over after thirty minutes.
Readout and evaluation of the digital flight data recorder from N1752K was performed by Thomas R. Jacky, Aerospace Engineer, NTSB, Washington, D.C. Readout information indicated the aircraft was at an altitude of 33,000 feet, on a heading of 159 degrees, and at position of 20.58 degrees north and 78.50 degrees west, at the time of the accident. About 800 feet of altitude was lost during the nose over and the occupants were subjected to a minimum of -0.37 G's and a maximum of +1.85 G's. See attached Factual Report of Investigation Digital Flight Data Recorder.
MEDICAL AND PATHOLOGICAL INFORMATION
One passenger received serious internal injuries as a result of the altitude deviation. One flight attendant received a serious rib injury as a result of the altitude deviation. The remainder of the passengers and flight attendants who reported injuries sustained minor cut, contusion, and strain injuries.
About 5 hours after the accident the three flight members submitted to toxicology testing in accordance with the American Airlines drug and alcohol testing program. The tests were negative for drugs and alcohol. (See attached toxicology reports.)
The aircraft was released to American Airlines on June 29, 1994, at 0530. The flight data recorder and cockpit voice recorder, which was retained by NTSB after the accident, was returned to American Airlines in September 1994.
|Learning Keywords:||Operations - Crew Resource Management|
|Operations - Upset in-flight (extreme attitudes, stall, spin)|
|Consequence - Flight Attendant Fatality - Injury|
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