Re: Swissair MD-11 (SR 111, JFK-GVA) crash off Nova Scotia

Date:         13 Oct 98 02:48:18 
From:         Alan Browne <>
Organization: Bell Solutions
References:   1 2 3 4 5
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SRG CAA wrote:
> > It should be noted that the aircraft does have a battery bus for
> > essential systems, and that the FDAU, FDR and CVR are part of these
> > systems.
> Not true.  The CVR and/or FDR do not need (by regulation) to be connected
> to the Battery Bus.  There is a good reason.  These two equipments will not
> help get you home safely in the event of an emergency where the whole
> battery capacity is needed.

This is confirmed by the report in AW&ST where as part of the SMOKE
drill, the electrical buses are switched to isolate the source of smoke.
During some configurations of electrical power in the drill, the CVR in
one case and the FDR in another are disconnected.  They are simply not
critical to keeping the aircraft in flight.  It is frustrating that
their data is not available.  The AW&ST report implied that the various
configurations were not the same accross all MD-11's.