It is a backup system, please tell me it must be selected, and is not "inadvertent" or "automatic"?
Also, Why only two Batteries? If both are "back up" what starts the show?
Back up batteries are used casually in line-service? Come on......
The reason we know? FAA requires a minimum charge for dispatch.
That is a sign that this battery needs to maintain a minimum energy for definition of its role. I don't think they are saying "Charge it before Launch".
"EMERGENCY USE ONLY" comes to mind....
Last edited by Lyman; 27th Jan 2013 at 17:24.