rarely does the passenger’s description match what actually happens on the airplanes instruments.

I have been in some pretty bad turbulence and even in the worst of it the altitude fluctuation on the altimeter is pretty minimal.

It doesn’t take much “drop” to scatter the cabin if it’s unexpected and abrupt.

This seems like a severe to extreme case of turbulence which by definition would mean the aircraft was probably at a time uncontrollable.

Even then I would be surprised if the drop wasn’t brief even though it was violent.

This came from an article posted on the board yesterday:

“After about 11 hours of flying time, the aircraft sharply dropped from an altitude of about 37,000 feet (11,278 metres) to 31,000 feet (9,449 metres) within five minutes as it crossed the Andaman Sea and neared Thailand, according to FlightRadar 24 data.“

That’s not a drop, that’s a descent and is exactly what the crew would have been trained to do in this situation. Descend to a lower altitude to try and find a better ride.