Machinbird
PIO as the word suggests doesn't happen. It is made to happen. Again we come back to the same point. First you make irrational pitch input then create PIO in roll and forget about the pitch totally and a training programme that caters for all this, You may have to select commercial pilots from aerobatic teams.
Vilas, unless you get hold of a defective aircraft, you yourself are never going to experience a roll PIO (also known as Aircraft Pilot Coupling) in your career, you already have the Low Gain touch.
BTW, I think your statement about the irrational pitch input is backwards with the creation of roll PIO. In AF447, The roll PIO started immediately. The pitch excursion followed in the next few seconds.
There have been videos of other Airbus pilots who have a large amplitude (High Gain) control technique that may well be a hazard when suddenly confronted with an unexpected drop to a roll direct condition-particularly if it happens in cruise. I do not know for a fact that this is an actual problem, but logic tells me that it should cause those people problems in that circumstance.
To suggest that a Pilot In the loop Oscillation (PIO) is made to happen is deceptive. Yes the pilot is driving the oscillation due to his control inputs.
No he is not doing it deliberately. He is merely using the controls in the manner that he has been accustomed to and is getting an unexpected and undesired result. The unusual behavior grabs your
full attention. This attention grab pulls the pilot out of his trained response pattern. It is as if a poisonous snake has suddenly been dropped onto your flight deck-it demands your full attention.
If you have never experienced a PIO, count yourself fortunate. They are rare but dramatic. The A320 has experienced roll PIO resulting in a missed approach on several occasions. I would not be surprised if the FCS has subsequently had its software modified in subtle ways to reduce the likelihood of future occurences.
Stopping a PIO is usually easy-just get out of the loop-let go of the controls. Then when the aircraft stabilizes, gently apply only the minimum control input necessary to achieve your objective. Has anyone reading this actually received training in this subject?
From what I am able to observe. the subject of PIO/APC is an aviation myth to most pilots. Something they will never confront and do not need to know about. Trying to explain PIO to professional aviators who have never seen it is like talking in a vacuum.
