It is an often repeated anecdote that the most frequently uttered phrase in a modern cockpit is, "what's it doing now?"
Contrary to common belief, airline pilots are not infallible gods of the sky. Well, ok they are but they are also human beings.
Programming errors happen all the time, a bit like how you press the wrong icon on your iPhone or click the wrong button on your TV
remote. That's why you keep checklists and human brains handy in the cockpit. Even a well trained crew makes errors perhaps once in a thousand actions. (Pilots without much experience are closer to one error per hundred actions). By errors here I don't mean flying off course or below glide path. I mean selecting the wrong mode or twisting the HDG knob the wrong way, or as in this case entering wrong information in the FMS.
Since errors are unavoidable, trying to eliminate them entirely is futile and counter-productive. The focus is on discovering and recovering from errors before they affect safety. As happened here. It hardly seems as if the flight was in danger. As Max Q says, the danger is when the crew does not take over and fly manually in the face of events which are obviously not going according to plan. If you don't understand what the automation is doing, disconnect and hand fly.
Even in basic instrument training in a plane far less sophisticated than a 777, my instructors impressed upon me the importance to monitor the automation (such as it was in a Cessna 172) and never hesitate to take over if I felt that events weren't going the way I felt they should. I can't tell you how many times I've engaged the autopilot and gone "whoa!" before immediately pressing the disengage button. Flying manually may be more work but I know exactly where the plane is going to go, meaning that at least the "aviate" bit is taken care of. Much better than trying to reprogram while also monitoring a deteriorating situation due to bad programming.
|Quoting 747megatop (Thread starter):|
This brings me to one question - How come sophisticated software such as one found on modern airplanes cannot do a simple validation on data entered and prevent invalid entries?
Look at it this way: What constitutes an invalid entry? How could the FMS "know" that the entered routing isn't the desired one.
Quite. They are really very basic computers by modern standards, and for good reason. Keep It Simple, Stupid!