not a "Tourist trap"
Hi tourist.
I appreciate it that you say I am making some good points!
About the question at the end (to save readers having to trace back I asked this "Question for the YES side."
"A pilotless airliner with 400 pax. is taking off in the correct configuration. At VR a system detects a changed status of a physical system. A/C protection software automatically reconfigures aircraft to settings appropriate to changed status. The new configuration puts a/c immediately outside the flight envelope and makes it almost incapable of flight. This condition had not been considered in any certification fault tree analysis.
(a) what do you envisage would happen to this pilotless a/c?
(b) which organisations will volunteer to be liable for the consequences?"
You replied "Your question is just a trap.
You are asking me to say what will happen after the computer has failed because nobody could think of the scenario, yet you have just thought of the scenario."
I take it you believe I am posing a false paradox - since I have thought of it, it can't be something that couldn't be foreseen. That would be true if I had "just thought of it", i.e. imagined it as a potential scenario.
The point is that I have not just imagined this scenario. The way I have phrased it is simply a generalised description of what happened to an acquaintance of mine 5 years ago.
During a B744 night takeoff, close to performance limits, the thrust reverser cowls on 2 engines independently moved rearwards as the aircraft accelerated. #3 at V1-25 kt, #2 9 seconds later at V1+ 9. They moved fractionally further than they should, triggering microswitches that sensed it as reverser activation.
System logic then was
"weight is on wheels, therefore a/c on ground.
>reversers are about to be deployed therefore a/c is landing
>possible exhaust gas damage to leading edge flaps when reversers deployed therefore retract LE flaps."
So at 0.7 seconds / 4kts before VR the LE flaps were retracted, with no warning to the crew.
At V2 the aircraft wheels left the ground. The a/c was just airborne in the dark with an intermittent stick shaker and very heavy buffeting making the instruments hard to read. Fortunately the First Officer who was PF recognised the buffet as being stall related, and maintained a very shallow climb to build up speed. After 7 seconds the air-ground logic caused the LE flaps to re-extend.
My point here is not to discuss the specifics, and I will grant that an automatic system would not have had the human pilots' handicap of difficulty in reading instruments and absence of external visual cues in the dark (although heavy buffet has been known to cause poor contact for avionics boxes).
It is that the humans on the spot were able to make some attempt to deal with this unforeseen situation. If they had not succeeded it would have been a major catastrophe with incalculable consequences especially for Boeing, as the possibility of such an occurrence had not been identified during amendment of the retraction logic.
This was nothing to do with reaction times and computer redundancy etc, it was physical objects in unpredicted circumstances. In the event, human pilot "instinct" saved the day, with NO analysis whatever of data. In this case, by pure good fortune the PF was an experienced aerobatic pilot and familiar with buffet, and one might question whether other pilots would have done so well. But that's really irrelevant to the questions.
So to come back to my question to you, which I've expanded slightly to cover the specific example:
(a) what do you envisage would happen to this pilotless a/c?
Would it follow the logic of "All engines are operating at VR, therefore raise nose and follow normal climb profile", which would be followed by a sustained stall warning leading to "follow stall recovery procedure and lower the nose (and hit the ground)".
or "An engine is about to go in reverse below V1, stop (and run off at high speed)"
or "Two engines are about to go in reverse above V1, stop (and run off at even higher speed)"
or "Two engines are about to go in reverse above V1, carry on (and do what?)"
or some other logic path, obtained from what analysis?
(b) which organisations will volunteer to be liable for the consequences?"
However, I reject the idea that "this is a "trap", because I am asking you to say what will happen after the computer has failed because nobody could think of the scenario, yet I have just thought of the scenario." I am using it as an example of something that neither I nor anyone else thought of, before it actually happened. I maintain that totally unpredicted and unpredictable events will continue to happen to both piloted and any pilotLESS aircraft, and want to know how the pilotless ones will deal with them.