The main concern is whether the computer controlled airspeed and altitude indicators malfunctioned.
The investigations are coming to that conclusion.
And when the airspeed and altitude data are incorrect, ( indicating to the flight control computers that the aircraft is flying too slow, or too low, or losing altitude, or all of those things, then the onboard flight computers are going to maximum thrust to regain speed and altitude. The result can be severe over-speed, with the possibility of the aircraft failing structurally, or a drmatic computer controlled mid-flight correction of the aircraftwhilst the computer is trying to make sense of bad data.
But if the flight is already at the correct altitude and at speed, then those adjustments could be disastrous. Such adjustments at altitude and at speed could make the aircraft pitch, and roll, and fly too fast for it's design.
As the pilots realize that something is wrong, the the plane is out of control now, and they take manual control of the aircraft from the computers and try, within seconds, to figure out what is happening, they may be in time to correct the aircraft's maneuvers and save it, as was the case in the other 2 incidences under investigation, or they may be too late, or make one wrong assumption and one wrong move, as it seems was the case with the Air France flight.
From the article,
"The first incident the NTSB is investigating occurred May 21, when a TAM Airlines A330 "experienced a loss of primary speed and altitude information while in cruise flight," according to a release from the NTSB.
"Initial reports indicate that the flight crew noted an abrupt drop in indicated outside air temperature, followed by the loss of the Air Data Reference System and disconnections of the autopilot and autothrust, along with the loss of speed and altitude information."
The TAM flight was on route from Miami to São Paulo, Brazil. It took the flight crew five minutes to regain control of the aircraft, according to the NTSB.
There's less detail about the second incident. The safety board said it "became aware of another possibly similar incident" that occurred on a June 23 Northwest A330 flight between Hong Kong and Tokyo.
In both cases, the planes landed safely and there were no injuries, the NTSB said."
In the first case, the aircraft's flight computers lost the information ( Air Data Reference System and disconnections of the autopilot and autothrust, along with the loss of speed and altitude information ) that it needed to fly the plane. Even as the flight crew saw this happen, and they took over control of the aircraft, the NTSB states that it took them 5 MINUTES to regain control.
When the aircraft is not 5 minutes above the earth, ( say just 4 minutes from the earth at 500 mph ), then this is a pretty big problem.
So, just to help you get it, the computers ( or sensors ) failed and this put the craft, crew, and passengers in a precarious position.
So although you may be right, the cruise control might not have been "on" during the crash, it is still being looked at as the culprit, because the cruise control was supposed to be on, getting good data from it's sensors, and working... yet it malfunctioned, resulting in loss of control of the aircraft, and these malfunctions are putting many lives at peril.