Singapore Airlines Flight 321
Boeing 777-312ER · Severe in-flight turbulence caused by convective clouds and thunderstorms
From London Heathrow Airport (LHR) to Singapore Changi Airport (SIN)
Event
- NTSB case
- DCA24WA185
- 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
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Final · TSIB final report, 18 May 2026
- Event fatalities
- 1 · all aircraft and ground
- Ground fatalities
- Unknown
- Occupants
- 229
- Survivors
- 228
- 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
- 79
- 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
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Not recorded
Boeing 777-312ER
- Flight
- SQ321
- Aircraft type
- Boeing 777
- Category
- Airplane
- 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
- 9V-SWM
- Operator
- Singapore Airlines
- Onboard fatalities
- 1
- Route
- From London Heathrow Airport (LHR)To Singapore Changi Airport (SIN)
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Non-U.S., Commercial
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Turbulence encounter
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Environmental issues › Conditions/weather/phenomena
- 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
Singapore Airlines Flight 321 was a scheduled international passenger flight operating from London Heathrow Airport in London, England, to Changi Airport in Changi, Singapore. On 21 May 2024, the Boeing 777 operating the flight, carrying 211 passengers and 18 crew members, encountered severe turbulence over the Irrawaddy River, Myanmar, resulting in the death of a passenger and leaving 79 crew and passengers injured. The aircraft was diverted to Suvarnabhumi Airport in Bangkok, Thailand.
Accident
On 20 May 2024, Singapore Airlines Flight 321 took off from London Heathrow Airport at 21:38 (22:38 British Summer Time) enroute to Singapore Changi Airport and the flight was initially uneventful. The flight was three hours away from landing in Singapore when at an altitude of 37000 ft, from 07:49:21 to 07:50:05, the aircraft encountered severe turbulence over the Irrawaddy River. Cabin crew members were in the midst of serving breakfast when the turbulence became sufficiently severe for unsecured passengers and objects to become airborne inside the cabin. Tracking data showed that the aircraft was at an altitude of 37000 feet at the time of the encounter.
Preliminary investigations suggested the flight experienced rapid vertical force changes and an altitude drop of around 177 ft The flight was then diverted to Bangkok, where it made an emergency landing at 15:45 Thailand Standard Time (08:45 UTC). Singapore Airlines dispatched a relief flight which carried 131 passengers and 12 crew members to Singapore the next morning.
Investigation and cause
Investigation
The investigation was held by the Transport Safety Investigation Bureau (TSIB), a department within the Ministry of Transport of Singapore, who had been delegated investigation duties by the Myanmar Transport Safety Branch. Data from both the flight data recorder (FDR) and cockpit voice recorder (CVR) were subsequently obtained by TSIB investigators, who arrived in Bangkok on the night of the accident.
The US National Transportation Safety Board was also reported to be sending an accredited representative and four technical advisers to support the investigation process as the accident involved an American-built aircraft.
Final report
The final report for the accident was released by TSIB on 18 May 2026. The report concluded that the aircraft had experienced severe turbulence caused by convective clouds and thunderstorms, resulting in air movements into a storm, strong updrafts, downdrafts and outflow winds. The report noted groups of convective clouds that had rapidly risen in height within 10 minutes before the accident occurred, and cited Singapore Airlines' analysis that the updraft at the accident site had an estimated wind speed of 8000–9000 feet (2400–2700 metres) per minute. During the turbulence, the aircraft experienced large changes in G-forces between -1.5G and +1.76G. The pilots had turned on the "fasten seat belt" sign but had insufficient time to make an announcement over the public address system, resulting in some passengers unable to fasten their seat belts in time and leading to a large number of injuries. Investigators also concluded that the weather radar may not have detected or under-detected the weather conditions over Myanmar during the flight, causing the pilots to be unaware of imminent weather, and noted that under-detection also occurred during the aircraft's ferry flight from Bangkok to Singapore. Investigators observed tests conducted by the weather radar manufacturer who concluded there was no evidence of failure but had observed irregularities during the test.
TSIB issued four recommendations. The first two recommendations were directed at Boeing and recommended the creation of guidelines for pilots and maintenance workers to determine to identify and respond to cases of the weather radar not detecting or under-detecting imminent weather. The third recommendation advised the weather radar manufacturer to devise a way to record weather display images to help resolve faults. The fourth recommendation, directed at the International Civil Aviation Organization, calls for aircraft with a maximum takeoff weight of above 27000 kg built before 2023 to be installed with systems that record information shown to pilots on their flight displays.
Text from the Wikipedia article “Singapore Airlines Flight 321” (revision 1374992215, 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: Singapore Airlines Flight 321
- Revision
- 1374992215 · 2026-09-15 · retrieved 2026-09-18
- Wikidata
- Q126010350
- Licence
- Text CC BY-SA 4.0, by the article's authors; Wikidata CC0; town positions GeoNames (CC BY 4.0)
NTSB record DCA24WA185
- Event ID
- 20240521194299
- Case number
- DCA24WA185
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Where each value comes from
- Record
- Wikipedia article "Singapore Airlines Flight 321" (page 76981438, revision 1374992215); merged with NTSB case DCA24WA185 (events / aircraft)
- Date
- Wikipedia infobox: date; matches the Transport Safety Investigation Bureau (TSIB), Ministry of Transport, Singapore (investigation delegated by the Myanmar Transport Safety Branch) final report
- Place and country
- Wikipedia infobox: site
- Map position
- Wikipedia: 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); gaps and aircraft details from NTSB record DCA24WA185
- Operation
- airline flight number in the infobox
- Fatalities
- Wikipedia: Wikipedia infobox: aircraft fatalities; matches the Transport Safety Investigation Bureau (TSIB), Ministry of Transport, Singapore (investigation delegated by the Myanmar Transport Safety Branch) final report
- Ground fatalities
- Wikipedia: not stated in the Wikipedia infobox
- Summary
- Wikipedia infobox: summary
Source notes (3)
- One occurrence in two sources, merged: the Wikipedia article "Singapore Airlines Flight 321" and NTSB case DCA24WA185, matched by the same aircraft registration and date. For this event outside the United States Wikipedia's values are used where the two differ; each value names its source.
- Filled from the NTSB case API where the bulk record had no value: coordinates. Values present in the bulk record are kept.
- Checked against the Transport Safety Investigation Bureau (TSIB), Ministry of Transport, Singapore (investigation delegated by the Myanmar Transport Safety Branch) final report (2026-05-18) on 2026-09-18. The report states the same date, fatalities, registration, operator, departure and destination. Not checked: place, crash-site coordinates, flight number, aircraft type, damage, type of operation and ground fatalities.