1. I understand that the dual input system is in place, however how does it work exactly in regards to the warning messages on the glareshield/PFD?
In the event of a simultaneous input on both sidesticks (2° deflection off the neutral position in any direction) the two green SIDE STICK PRIORITY lights on the glareshield come on and "DUAL INPUT" voice message is activated.
2. How does the autopilot/priority button on the side-stick work (in terms of how long it needs to be pressed for)?
A pilot can deactivate the other stick and take full control by pressing and keeping pressed his priority takeover push button.
For latching the priority condition, it is recommended to press the takeover push button for more than 40s.
This allows the pilot to release his takeover push button without losing priority.
However, a pilot can at any time reactivate a deactivated stick by momentarily pressing the takeover push button on either stick.
If both pilots press their takeover push buttons, the pilot that presses last gets priority.
Note: If an autopilot is engaged, any action on a takeover push button disengages it.
In a priority Situation:
- A red light comes on in from of the pilot whose stick is deactivated.
- A green light comes on in front of the pilot who has taken control, if the other stick is not in the neutral position (to indicate a potential and unwanted control demand).
3. If anyone has ever encountered a dual input situation, is the system in place effective enough and clear to gain an immediate understanding of who has control?
In a pure dual input scenario both stick inputs will be algebraically added and the sum of both inputs will be used by the FBW system. Therefore they both are in command. That system is very unintuitive in my opinion but difficult to built otherwise without force feedback. A priority situation is pretty clear on the other hand, but takes some getting used to especially if coming from a conventional airplane.