SQ321 incident: Parts of aircraft's weather radar system sent to US for tests, findings pending

Straits Times

27-05-2025

In an interim update, Singapore investigators revealed 79 passengers were injured in the incident.
SQ321 incident: Parts of aircraft's weather radar system sent to US for tests, findings pending
SINGAPORE - Components of the weather radar system on board Singapore Airlines Flight SQ321, which experienced sudden extreme turbulence in 2024, have been sent to the United States for examination and testing.
However, the results of the examination and tests are still pending and the final accident report will be made public after the investigation has concluded, said Singapore transport investigators looking into the incident, which left one passenger dead and 79 injured.
The Transport Safety Investigation Bureau (TSIB), a department within Singapore's Ministry of Transport, gave this update in an interim statement on May 27, six days after the first anniversary of the ill-fated flight on May 21, 2024.
The TSIB said investigations into the turbulence event are under way and being conducted in accordance with international requirements.
The bureau said it is also being assisted by investigators from the US' National Transportation Safety Board and Federal Aviation Administration, with support from aircraft manufacturer Boeing as well as other parties.
According to international guidelines for aircraft accident investigations, states are required to issue a preliminary report within 30 days of the accident and a final report within 12 months, if possible.
If not, an interim statement detailing the progress of the investigation should be released annually on the anniversary of the accident.
The TSIB had on May 29, 2024, released a set of preliminary findings on the turbulence incident, which happened about 10 hours after the Boeing 777-300ER plane carrying 211 passengers and 18 crew departed London for Singapore.
The bureau found that the wide-body jet started to vibrate while cruising at 37,000 feet over the Irrawaddy Basin in Myanmar. At the same time, the aircraft, which was on autopilot, rose rapidly to 37,362 feet and started to pick up speed.
This happened during meal service at 3.49.21pm Singapore time. At 3.49.32pm, the pilots turned on the 'fasten seat belt' sign as they tried to manage the plane's airspeed.
Eight seconds later, the plane experienced rapid changes in G-forces as it fell 178 feet, or about 54m, TSIB said.
G-forces measure acceleration or deceleration by comparing it with the normal pull of gravity on earth. At positive 1.5G, for instance, a person would feel like they were 1.5 times their body weight.
According to the TSIB, the plane went from positive 1.35G at 3.49.40pm to negative 1.5G in less than a second, before returning to positive 1.5G within four seconds. This likely caused unbelted passengers and crew to be flung up into the air and back down, injuring them.
A 73-year-old Briton, Mr Geoffrey Kitchen, died of a suspected heart attack. Many others, including passengers from Malaysia and Australia, suffered serious injuries involving the head and spine.
A medical emergency was declared, and the plane was diverted to Bangkok's Suvarnabhumi Airport.
In the immediate aftermath, several sources like AccuWeather pointed to rapidly developing thunderstorms near SQ321's flight path as a likely cause of the extreme turbulence.
The commercial weather forecaster noted then that such explosive thunderstorms often have strong currents of rising air, sometimes at more than 160kmh, which can cause a severe change in altitude in a short amount of time.
Some have questioned if Flight SQ321 could have avoided the turbulence, noting that other planes in the area had flown around the thunderstorms at the time.
Based on ST's checks, for example, Swiss International Air Lines Flight LX181 from Bangkok to Zurich was flying in the same vicinity as SQ321 on May 21, 2024.
The national airline of Switzerland had told The Straits Times that its pilots made 'significant course deviations' that day, using onboard weather radar to navigate around severe weather conditions.
Under Singapore law, TSIB's final investigation report on the SQ321 incident will not be admissible as evidence in court, except during a coroner's inquiry.
But its findings will likely colour what is expected to be a lengthy legal battle between SIA and the affected passengers, some of whom suffered life-changing injuries and remain scarred from the experience.
Even with the compensation offers it has made, the national carrier is set to face lawsuits that could span multiple countries. Based on precedents, these are likely to end in confidential settlements, which could possibly go into millions of dollars for the serious cases, legal experts have said.
Claims against SIA must be settled or brought to court by the second anniversary of the SQ321 incident in 2026.
Kok Yufeng is a transport correspondent at The Straits Times.
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