Good point Alek
I remember the Qantas incident could this be the same..see below
In the October 7 incident, on Qantas flight QF72 from Singapore to Perth, passengers were hurled around the cabin after the Airbus A330 aircraft dropped with two plunges of 20 and 16 seconds 200 and 650 metres in a matter of seconds while flying over the Indian Ocean. The pilot was forced to make an emergency landing at Learmonth, 1200 kilometres north of Perth on the Western Australian coast, and 44 passengers required hospital treatment.
The Australian Transport Safety Bureau said it believed a faulty component, called the air data inertial reference unit (ADIRU), caused the problem by feeding "erroneous and spike values'' about the angle at which the plane was flying to a flight control computer.
"This led to several consequences, including false stall and over speed warnings,'' and later generated very high and incorrect values for the aircraft's angle of attack. This led to the flight control computers commanding the aircraft to pitch down.
On this flight the plane acted of its own accord even after the pilot had taken manual control of the aircraft but minutes later, the plane made two downward plunges.
This was a situation which nobody have seen it before.
He who laughs last obviously has'nt heard the bad news.