Actually there are many, but I'll stick to the most obvious.
1. On the 757/767, the computer is not in control. The pilot had absolute and final control over where the aircraft goes, they are not fly-by-wire aircraft, the pilots move the control surfaces via control cables, pulleys and push rods. There is an autopilot input to the hydraulic actuators, but that is overridden by any pilot input.
2. The ATC transponder is a low data-rate device. The smarter ones can transmit and receive altitude information, but they certainly cold not support the data-rates needed to provide controllable flight.
3. The ATC transponder is not connected to the autopilot. Why should it be? All it does is squawk an ident and altitude info for ground control/TCAS. Altitude is received from the Air Data Computer, not the autopilot.
Since (thanks to the irresponsibility of the press) everyone knows that the transponder is used to signal a hijack, isn't it possible that the hijackers knew this and prevented the pilots changing the squawk code? It isn't hard to disable the Cockpit Voice Recorder either, it's as simple as pulling a circuit breaker. |
