Originally Posted by
70 Mustang
Are you asking about a physical failure of the bus DC1 or DC2 or just a failure of power to the bus?
Thanks for taking the time to respond.
No, my question relates to a failure of the Bus itself. I can see from our systems handbook how each DC Bus has several power sources.
My Airbus manuals disappeared from my IPAD the moment I changed fleets so I am relying on my memory but in the A320 with a DC Bus fault, ECAM would not only tell you what has failed but also which systems are lost (fuel pump/window heat for example) and what to expect upon landing (landing capability for example).
The QRH in the 737 we have does not include a checklist for dealing with the loss of a DC Bus and as you say there are SOME references to the power source of systems but there is no master list of which systems would be affected by the loss of a DC Bus.
We can figure out which Bus is lost based on the Volts of the various TR units BUT sitting there in the middle of the ocean, having established that a DC Bus has failed, there is no guidance as to which systems are lost except for the obvious significant system failures associated with a MC.
However, there are other subsequent failures that the loss of a DC Bus will cause that will not be annunciated by a fail light or a MC and have no checklist in the QRH.
A simple example that comes to mind is windshield wipers. If they are DC powered like on the A320 (and my manuals dont tell me if they are or not) then we will not have them available upon landing. HF radios also, no fail light and probably DC powered.
I fully recognize that its an unlikely occurance and that most things can be dealt with by stepping through the various obvious failures with the QRH in hand however I am surpised there is no quick reference summary page of systems remaining following such a Bus failure.