China Southwest Airlines Flight 4509
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A China Southwest Airlines Tupolev Tu-154M Similar to the one involved
|Date||February 24, 1999|
|Summary||Mechanical failure of aircraft tail section caused by improper maintenance|
|Site||Wenzhou, Zhejiang, China|
|Aircraft type||Tupolev Tu-154M|
|Operator||China Southwest Airlines|
China Southwest Airlines Flight 4509 (SZ4509) was a flight from Chengdu Shuangliu International Airport, Sichuan to Wenzhou Yongqiang Airport, Zhejiang. On February 24, 1999 it crashed into a field while on approach to Wenzhou Airport, killing all 61 passengers and crew members on board. Witnesses saw the plane nose dive into the ground from an altitude of 2,300 feet and explode.
Following the incident all Tupolev Tu-154 aircraft in China were taken out of service.
- Model: Tupolev Tu-154M
- Registration: B-2622
- Serial Number: 90A-846
- Engine: Soloviev D-30
- Year of Delivery: 1990
- Captain: Yao Fuchen (姚福臣);
- First Officer: Xue Mao (薛冒);
- Flight Engineer: Guo Shuming (郭树铭);
- Flight Navigator: Lang Zhanfeng (郎占锋).
Incorrect locknuts had been installed in the elevator operating system. These spun off during the flight, leaving the elevator uncontrollable.
In 2002, China Southwest merged with Air China. Air China did not retire the flight number, but its destination airport was changed from Wenzhou Yongqiang Airport to Shanghai Pudong International Airport. As of February 25, 2014, the route is flown using an Airbus A320. 
- China Southwest Airlines Flight 4146, another aviation disaster caused by poor maintenance.