Keep your seatbelts fastened. Snugly.
Another Boeing airplane (777 this time) exhibited a sudden altitude drop during turbulence over SE Asia. One passenger with a heart condition died; seven are in critical condition.
In March, a Boeing 787-9 Dreamliner lost elevation on a flight from Oz to NZ. Reportedly an uncovered cockpit switch was involved. Boeing “recommended that airlines inspect the cockpit seats the next time they perform maintenance on their 787s”.”
@kegill Non-Boeing airplanes aren't immune to turbulence either.
In this case, the plane and its manufacturer are irrelevant. The weather is at fault.
And the "rapid descent" was intentional, to get out of the rough air, not a second problem.