Singapore Airlines Flight Went Awry in 4.6 Seconds

A bevy of investigators have pieced together a chronology of events on the Singapore Airlines flight that ran into extreme turbulence last week—including 4.6 terrifying seconds. Singapore's Transport Ministry, the FAA, the US National Transportation Safety Board, and Boeing have completed their preliminary analysis of the flight's data and cockpit voice recorders. Per the AP and the Guardian, they report the following regarding the May 21 Singapore-bound flight from London, which ended with one man dead and 26 people still hospitalized as of Wednesday:

• The aircraft was crossing the southern portion of Myanmar at 37,000 feet when it started to vibrate due to changes in the gravitational force.
• The plane responded by climbing to 37,362 feet; it increased its speed, possibly due to an updraft.
• The plane's autopilot then tried to pitch the jet downward to its previous altitude.
• "The aircraft experienced a rapid change in G (gravitational force) ... this likely resulted in the occupants who were not belted up to become airborne," the Transport Ministry noted.
• "The vertical acceleration changed from negative 1.5G to positive 1.5G within 4 seconds. This likely resulted in the occupants who were airborne to fall back down. The rapid changes in G over the 4.6 seconds duration resulted in an altitude drop of 178 feet, from 37,362 feet to 37,184 feet. This sequence of events likely caused the injuries to the crew and passengers."
• The BBC points out the altitude drop's distance is roughly equal to the height of the Leaning Tower of Pisa.
• As the turbulence was occurring, the pilot could be heard announcing that the "fasten seatbelt" sign had been switched on.
• Recorded data shows the pilots assumed manual control of the plane for 21 seconds to stabilize it, then reengaged the autopilot.
• About 17 minutes later, the pilots began making a normal and controlled descent from 37,000 feet. There was no further turbulence, and the aircraft landed in Bangkok.

(More Singapore Airlines stories.)