On 21 May 2024, Singapore Airlines Flight SQ321 encountered severe turbulence over Myanmar, killing one passenger and injuring 104 others in one of the most widely reported aviation safety incidents of the year. The event — the first turbulence-related fatality in commercial aviation in more than two decades — refocused industry and regulatory attention on the hazards of convective weather at cruise altitude and the limitations of current turbulence forecasting technology.
What happened
Flight SQ321 had departed London Heathrow bound for Singapore Changi Airport on the evening of 20 May, with 211 passengers and 18 crew members on board. The Boeing 777-300ER was cruising at 37,000 feet when, at approximately 07:49 UTC on 21 May, it encountered a region of severe convective activity over Kanasoekone in Myanmar’s Myaungmya District. Within fractions of a second, the aircraft experienced an extreme change in vertical acceleration — dropping from +1.35G to −1.5G in just 0.6 seconds. Unsecured passengers and objects were thrown into the cabin ceiling with considerable force.
A 73-year-old British man died from what was attributed to a suspected cardiac event, believed to have been precipitated by the violent acceleration forces. Thirty passengers sustained serious injuries, several involving traumatic spinal and head trauma. A further 74 received minor injuries. Twelve cabin crew members were also hurt, having been in the process of serving breakfast when the aircraft was struck. The crew declared a medical emergency and diverted the aircraft to Bangkok’s Suvarnabhumi Airport, where it landed at 15:45 local time.
The encounter occurred in a region of rapidly developing cumulonimbus cells that the aircraft’s weather radar may not have adequately detected. Preliminary analysis suggested the storm systems were in an early, fast-evolving stage at the time of the encounter — a characteristic that makes them particularly difficult to identify and circumnavigate using standard airborne radar returns.
Why it matters
The SQ321 incident revived longstanding questions about the adequacy of onboard weather radar technology in detecting convective turbulence, particularly when cumulonimbus clouds are in their formative stages and have yet to develop the dense precipitation that radar is most effective at identifying. The aviation industry has long recognised clear-air turbulence — which occurs away from visible cloud and is undetectable by any current radar system — as an intensifying risk associated with climate change and the destabilisation of high-altitude jet streams. Although SQ321’s encounter was convective rather than clear-air in origin, the incident sharpened the broader debate about whether current forecasting and detection tools are adequate for the turbulence environment that airlines will face in coming decades.
The death of a passenger — the first such turbulence fatality in commercial aviation since 1997 — also underscored the critical importance of seatbelt compliance throughout a flight, not only when the fasten seatbelt sign is illuminated.
What comes next
Singapore’s Transport Safety Investigation Bureau (TSIB) published a preliminary report on 29 May, confirming the G-force profile of the event and noting that the autopilot had attempted to correct an uncommanded altitude excursion in the seconds following the initial strike. The full investigation was expected to examine the performance of the aircraft’s weather radar system, the adequacy of pre-flight meteorological briefings for the route, and whether procedural changes to crew positioning and service protocols in convective-weather zones were warranted. Singapore Airlines subsequently reviewed its in-flight service procedures and reinforced guidance to passengers on seatbelt use during cruise flight.
Key vocabulary:
- convective turbulence – turbulence caused by rapidly rising columns of warm, moist air, typically generated by developing thunderstorm cells or cumulonimbus clouds
- cumulonimbus – a tall, dense storm cloud associated with thunderstorms and heavy turbulence; the most hazardous cloud type for aviation
- clear-air turbulence – turbulence occurring in cloudless air, usually near the jet stream; invisible to radar and impossible to detect with current technology
- G-force – a measure of acceleration relative to gravitational force; a rapid shift from positive to negative G forces unsecured objects — and people — into the air
- circumnavigate – to fly around an obstacle or hazard, such as a storm system, rather than through it
- precipitated – caused or triggered, especially when the event happens more suddenly or severely than expected
- diversion – the rerouting of a flight to an unscheduled airport, typically due to a medical emergency, technical issue, or safety concern
CEFR Level C1 / ICAO Level 5-6