China Southwest Airlines Flight 4509
Tupolev Tu-154M · Improper maintenance, loss of control
From Chengdu Shuangliu International Airport (CTU) to Wenzhou Longwan International Airport (WNZ)
Event
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- Event fatalities
- 61 · all aircraft and ground
- Ground fatalities
- Unknown
- Occupants
- 61
- Survivors
- 0
- InjuriesFatal: death within 30 days. Serious: over 48 hours in hospital within a week, most broken bones, severe bleeding, nerve or organ damage, or serious burns. Minor: anything less. Glossary
- 7 · all on the ground
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
Tupolev Tu-154M
- Aircraft type
- Tupolev TU-154
- Category
- Airplane · from aircraft type
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- B-2622
- Operator
- China Southwest Airlines
- Onboard fatalities
- 61
- Route
- From Chengdu Shuangliu International Airport (CTU)To Wenzhou Longwan International Airport (WNZ)
Cause areas
- Aircraft › Aircraft handling/service
- Aircraft › Aircraft systems
From the investigation findings the Wikipedia article reports, sorted into the NTSB's cause areas with AI assistance.
Approximate · Coordinates from the Wikipedia article; not checked against an investigation report.
From the Wikipedia article
China Southwest Airlines Flight 4509 (SZ4509) was a domestic flight in China from Chengdu Shuangliu International Airport, Sichuan to Wenzhou Yongqiang Airport, Zhejiang. On February 24, 1999, the Tupolev Tu-154M operating the flight crashed while on approach to Wenzhou Airport, killing all 61 passengers and crew members on board.
Accident
On 24 February 1999, the crew was preparing the aircraft for landing at Wenzhou Airport. The flaps were extended at 1000 m, but seconds after, the aircraft's nose lowered abruptly, the aircraft disintegrated in mid-air and crashed into an area of high ground, and exploded. Witnesses saw the plane nose dive into the ground from an altitude of 700 m and explode. All 61 people on board were killed. Several people on the ground were injured from debris.
Investigation and cause
Cause
Incorrect self-locking locknuts had been installed in the elevator operating system, which maintenance crews failed to notice. These spun off during the flight, leaving the elevator uncontrollable. This disabled the aircraft's pitch channel, causing the crash.
Text from the Wikipedia article “China Southwest Airlines Flight 4509” (revision 1339316674, retrieved 2026-09-18) by its authors, under CC BY-SA 4.0. Extracted as plain text: references, tables, images and some sections are left out. Read the article
Sources
Wikipedia article: China Southwest Airlines Flight 4509
- Revision
- 1339316674 · 2026-02-19 · retrieved 2026-09-18
- Wikidata
- Q671604
- Licence
- Text CC BY-SA 4.0, by the article's authors; Wikidata CC0; town positions GeoNames (CC BY 4.0)
Where each value comes from
- Record
- Wikipedia article "China Southwest Airlines Flight 4509" (page 10132619, revision 1339316674)
- Date
- Wikipedia infobox: date
- Place and country
- Wikipedia infobox: site
- Map position
- Wikipedia article coordinates
- Aircraft, operator and route
- Wikipedia infobox: aircraft type, registration, operator, origin and destination; route airports from the linked airport articles' Wikidata codes (OurAirports)
- Operation
- flight number in the article title
- Fatalities
- Wikipedia infobox: aircraft fatalities
- Ground fatalities
- not stated in the Wikipedia infobox
- Summary
- Wikipedia infobox: summary
Source notes (1)
- Wikipedia · Facts from the Wikipedia article's infobox and coordinates, not checked against an investigation report. Independent review pending.