Nearly two years after Singapore Airlines flight SQ321 hit severe turbulence over Myanmar, killing one passenger and injuring 79 others, investigators have released their final report. The conclusion, in essence: we still don’t fully know what happened.

Meaning, the unexpected turbulence is still a mystery.

The Transport Safety Investigation Bureau (TSIB) found the on-board weather radar on the Boeing 777-300ER may have failed to detect the storm clouds that triggered the May 2024 incident, but stopped short of confirming it. While the radar manufacturer’s own testing found no fault, TSIB noted the possibility of failure “cannot be ruled out” – particularly given maintenance records showing the same aircraft’s radar had failed to display weather conditions as recently as six days before the incident.

What makes the finding more troubling is that three other aircraft flying over the same region at the time spotted widespread clouds and deviated accordingly, using their own weather radars – which differed from the model fitted to SQ321.

The pilots, meanwhile, saw nothing. Both the radar display and their own visual checks of the flight path indicated clear skies. Investigators said they were “unable to understand” why the crew did not see the widespread clouds other flight crews could clearly identify.

The turbulence itself was severe. The aircraft experienced a vertical acceleration drop from +1.35G to -1.5G – then back up to +1.5G – within 4.6 seconds, likely caused by a rapidly growing cloud and an updraft estimated at 8,000 to 9,000 feet per minute.

TSIB’s recommendations focus on closing the gaps the investigation exposed: mandating weather radar recording functions on older aircraft, improving troubleshooting guidance for crews and maintenance teams, and developing ways to log what pilots actually see on their navigation displays. The SQ321 aircraft entered service in 2008, predating requirements for that recording capability.

SIA said it has since improved its turbulence monitoring tools, updated crew guidance on suspected radar malfunctions, and begun reporting such issues directly to Boeing and the radar manufacturer.

For the travel industry, the report is a reminder that severe turbulence on planes remain difficult to fully predict or prevent. So when flying it is wise to stay in your seat with your seat belt firmly on. And only move around the cabin when necessary, such as when going to the toilet.

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