Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Fri, 01 Nov 2002 10:12:02 -0500
Message-ID: <redirect-1850335@logan.com>
From: "Gary Casey" <glcasey@adelphia.net>
Subject: electrical redundancy
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<<So, if I understand it correctly, the EPS V8, which is electrically
dependent, only has one alternator?  All that technology, and only one
alternator?  I don't get it.........  The people that are putting these in
Lancairs, is this the configuration you are installing them with?  Being a
EE, and with all the technology out there, especially on an electrically
dependant engine, there is NO way I'd even sit in it without dual alt/dual
bat system.>>

There are a number of ways to provide the necessary redundancy and certainly
the dual alternator/dual battery approach is a good one.  I think the
important thing is to make sure that the engine operation can be isolated
from all the rest of the requirements - or not if required.  It sounds like
the engine was isolated in this case, but it apparently (repeat, apparently)
did not have a redundant system.  A single alternator/dual battery system
could have done that as could a single battery/dual alternator.  For the
twin engine application with a 24-volt aircraft one could build a system (I
did) that could run on either 24 or 12 volts, thereby allowing the 24-volt
system to be a viable backup.  Also, I note that apparently (I repeat,
apparently) the system would not run with a supply below 9 volts.  All
contemporary automotive systems will operate down to 6 volts (mine will) and
that would have given at least a few more minutes of operation.  Finally, I
firmly believe that ANY important system should have an active warning
device, not just a gage, to warn of a failure.  Was the pilot flying the
whole trip with a warning light staring him in the face?  Or did he ignore
it?  I expect we will never know.

And then even with one engine out, that still doesn't provide the cause of
the crash.  Unless there was, as reported, only one 12-volt alternator that
charged a battery for each engine (or....?) and therefore one engine would
fail only to have the other fail a few minutes later and maybe both were
gone.

Regardless of all that it appears as though the engine itself suffered no
failure and this has been typical of the "auto engine" conversions of which
I am aware.  The engine itself seems to be as rugged as its "aircraft
engine" cousin.

Gary Casey