Narrative:
China Southwest Airlines flight SZ4509, a Tupolev Tu-154M, departed Chengdu Airport in China at 14:35 hours on a domestic flight to Wenzhou. The en route altitude was 11400 meters.
At 16:02 hours, when the aircraft passed 9000 meters in the descent towards Wenzhou, the crew felt that the steering column was too far forward. The crew were puzzled by the control issue, especially at 16:26 hours when the steering column was fully forward. Yet, the aircraft was not in a nose-down attitude. The captain noted that the controls felt disconnected. At 16:29 the flight was cleared to descend from 1200 m to 700 m. When the flight crew selected the first stage of flaps, an angle-of-attack warning sounded in the cockpit. The aircraft entered a stall and began a steep descent until it impacted a farm field at Rui'an.
Several farmers were injured by the flying debris.
PROBABLE CAUSE: A self-locking nut, other than castle nut with cotter pin as specified, had been installed at the bolt for connection between pull rod and bellcranck in the elevator control system. The nut screwed off, resulting in bolt loss, which led to the loss of pitch control.
Elevator issue
Loss of control
» Soviet Transports
» todayonhistory.com
accident date: 24-02-1999
type: Tupolev Tu-154M
registration: B-2622
| Status: | Accident investigation report completed and information captured |
| Date: | Wednesday 24 February 1999 |
| Time: | 16:34 |
| Type: |  Tupolev Tu-154M |
| Operator: | China Southwest Airlines |
| Registration: | B-2622 |
| MSN: | 90A846 |
| First flight: | 1990 |
| Total airframe hrs: | 14135 |
| Cycles: | 7748 |
| Engines: | 3 Soloviev D-30KU-154-II |
| Crew: | Fatalities: 11 / Occupants: 11 |
| Passengers: | Fatalities: 50 / Occupants: 50 |
| Total: | Fatalities: 61 / Occupants: 61 |
| Aircraft damage: | Destroyed |
| Aircraft fate: | Written off (damaged beyond repair) |
| Location: | Rui'an ( China)
|
| Phase: | Approach (APR) |
| Nature: | Domestic Scheduled Passenger |
| Departure airport: | Chengdu Airport (CTU/ZUUU), China |
| Wenzhou Yongqiang Airport (WNZ/ZSWZ), China | |
| Flightnumber: | 4509 |
China Southwest Airlines flight SZ4509, a Tupolev Tu-154M, departed Chengdu Airport in China at 14:35 hours on a domestic flight to Wenzhou. The en route altitude was 11400 meters.
At 16:02 hours, when the aircraft passed 9000 meters in the descent towards Wenzhou, the crew felt that the steering column was too far forward. The crew were puzzled by the control issue, especially at 16:26 hours when the steering column was fully forward. Yet, the aircraft was not in a nose-down attitude. The captain noted that the controls felt disconnected. At 16:29 the flight was cleared to descend from 1200 m to 700 m. When the flight crew selected the first stage of flaps, an angle-of-attack warning sounded in the cockpit. The aircraft entered a stall and began a steep descent until it impacted a farm field at Rui'an.
Several farmers were injured by the flying debris.
Probable Cause:
PROBABLE CAUSE: A self-locking nut, other than castle nut with cotter pin as specified, had been installed at the bolt for connection between pull rod and bellcranck in the elevator control system. The nut screwed off, resulting in bolt loss, which led to the loss of pitch control.
Classification:
Wrong installation of partsElevator issue
Loss of control
Sources:
» ICAO Adrep» Soviet Transports
» todayonhistory.com
Photos
accident date: 24-02-1999
type: Tupolev Tu-154M
registration: B-2622
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Chengdu Airport to Wenzhou Yongqiang Airport as the crow flies is 1654 km (1034 miles).
Accident location: Exact; as reported in the official accident report.
Distance from Chengdu Airport to Wenzhou Yongqiang Airport as the crow flies is 1654 km (1034 miles).
Accident location: Exact; as reported in the official accident report.
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
languages: 
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Tupolev Tu-154
- 1026 built
- 55th loss
- 28th fatal accident
- 15th worst accident (at the time)
- 23rd worst accident (currently)
China- 7th worst accident (at the time)
- 9th worst accident (currently)
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