Originally Posted by
Old Carthusian
There are two problems with that argument. Firstly, distance - at the distance in the cockpit the difference between audio and visual perception is so infinitesimal as to be totally disregardable. Understanding and interpretation are the key.
Firstly, I suspect your making the assumption that the visual information and sound information are of same duration, which is not correct.
The visual information duration needed is a fraction of a second.
The sound information duration is the time needed to pronounce the words, perceive the words, and transpose that mentally in a mental visual image of what that means - a couple, to perhaps several seconds.
That difference of a couple, to several seconds, is not infinitesimal in my math at all - particularly when the time to take actions is very limited, measured in seconds, or tens of seconds.
The second issue is that visual perception is worthless without a frame of reference and that is why a yoke is no more superior than a sidestick. A yoke moves - how far is a significant movement? Who decides the frame of reference?
With direct visual contact, a move of the control beyond a certain position is sufficient to trigger a first visual warning.
After the first visual warning the observer can perform a closer observation, which can render more accurate information.
This is were my example of race car driving practice comes into play.
The visual observer is a pilot, so the visual frame of reference is developed during training, and developing awareness in the cockpit. Time needed is a lot less than duration of training.
Using visual contact does not mean excluding other means, those means, which you're suggesting. In fact I believe using all means is a current routine practice with controls were visual and tactile contact is possible.
Which brings forward, that adding the "tactile information channel" - remove (optionally, or not) the independence - is only a plus.