Did this happen close to the ground? If so, I doubt the pilot would have had time to open the alt air before the crash.I had spoken to Van's engineers about that same question. when I was building. They had just introduced a free retrofit kit. They mentioned that there was an occasion where the fab had swallowed a garbage bag (or some similar debris), resulting in an air intake blockage, and subsequent engine stop...
...The first version of the bypass was poorly designed and a potential hazard. The second version looks a little better, but I elected not to install it. The hazard that it was meant to deal with, an air filter blocked by snow, is easily dealt with by proper application of alternate air/ carb heat.
I wouldn't install it.
This is Van's slide door converted to a magnet pop-off like C-200's navajos, etc. That's all I'm using. No front door to fall apart, no cables, no heat (IO-540).
The newer system works well, just DO NOT rivet to the FAB (Fiberglass) use screws, loctite and steel lock nuts when doing the install. .