May 21, 2024

What Caused the Severe Turbulence on a Singapore Airlines Flight Last Night?

 The media is full of stories about a terrible turbulence event on a Singapore Airlines flight from  London to Singapore last night.  One person was killed and dozens were injured.

The event occurred over the water offshore of Myanmar (the location shown on the map below) at 0807 UTC this morning (21 May).

The FlightAware website provides the minute-by-minute flight information during the critical period.  The last column shows the change in elevation each minute.

Wow.  Sudden declines in altitude starting around 7 minutes after the hour.


I suspect I know what happened.  They ran into turbulence associated with thunderstorms.

Here is a visible satellite image 3 minutes after the incident (from the Japanese geostationary weather satellite).  The plane's location is shown by an arrow.


Even better, below is a close-up infrared satellite image that is color-enhanced.  Infrared images tell us the height of the clouds.  At the time of the accident, the aircraft was approaching a convective cell (thunderstorm).


Substantial turbulence is quite possible in such a location.

There is extreme turbulence at the top of thunderstorm cells and in the near environment, as atmospheric waves (gravity waves) can propagate away from the thunderstorms (see graphic below).

(Based on Hooke, 1986; by permission of the American Meteorological Society)






5 comments:

  1. It's best to keep your seat belt fastened and to move around in the cabin only when you have to. That said, if you are on a long flight, then you do have to get up to take a short walk occasionally. But when you are back in your seat, fasten the belt.

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  2. ITCZ. Always been a dangerous place for ships and aircraft as it is a perpetual thunderstorm breeding ground. Especially in the shoulder seasons. Pilots have to navigate between storm cells in a "threading the needle" type of fashion. Can be some very scary flying.

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  3. Yes, always keep that seatbelt on! I've flown into and out of New Orleans for Mardi Gras through conditions that were downright terrifying (to me), white-knuckle flights ("kiss the ground when you land" flights). Very interesting post. Thanks!

    ReplyDelete
  4. Juan Browne at the Blancolirio aviation safety channel on Youtube makes this report of the incident:

    https://www.youtube.com/watch?v=0UYNFthOx1o

    Browne is a 777 first officer. He notes that an airliner’s forward-looking weather radar cannot see a weather system which is developing behind the weather immediately in front of the aircraft.

    A pilot can take actions to deal with weather which can be seen, but can’t prepare for weather which is hidden behind another system.

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    Replies
    1. No but a pilot can use other information to avoid convective weather completely. I suspect crew training and competence problems - same as what caused the 737 MAX crashes (no, those crashes were the pilot's fault, not Boeing's).

      Delete

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