A former Qantas captain who spent nearly four decades flying between
London, Singapore and Australia has said the extreme turbulence which
struck a Singapore Airlines Boeing 777-300ER over the Bay of Bengal this
week was not unusual for the time of year.
Singapore Airlines has apologised to those affected by the
devastating experience, which left one man dead and dozens injured among
the 211 passengers and 18 crew onboard SQ321.
David Evans said when he was flying the route with Qantas, he learned
there are particular challenges pilots face, “especially at this time
of year”.
He said the Bay of Bengal, between the subcontinent of India and the Malaysian Peninsula, was notorious for severe turbulence.
“This time of year, the Inter-tropic Convergence Zone, or ITZ, is very active. That’s a fancy aviation name for the monsoon.
“Those ancient trade winds collide somewhere close to the equator.
That collision line is the ITZ, and it moves north or south of the
equator depending on the season.”
Evans said when the two meet, those opposing trade winds must go
somewhere, creating instability in the atmosphere that can translate
into severe weather and turbulence, “and a bumpy ride if you’re flying
near them”.
Mark Hofmeyer, a current pilot and vice president of the Australian
International Pilots Association, said the tragic incident was likely
caused by thunderstorms, or convective turbulence, rather than clear air
turbulence. “Clear air turbulence is normally associated with a jet
stream, a really strong core of air.
“You don’t get many jet streams around the equator, which is where
this happened. What you have up there though, is you get really big
storms. Big puffy clouds, lots of air moving up, lots of air moving
down, big thunderstorms.”
Singapore Airlines CEO Goh Choon Phong has apologised for the
incident, saying the airline is "deeply saddened" and expressed his
"deepest condolences" to the family and loved ones of the deceased.
The Bangkok Post says 58 passengers from the flight – which was
diverted to Bangkok – remain in hospital in the city, 18 in intensive
care.