Karl-Heinz Kuenzel wrote:
Hi.

Here in Germany we had an accident with a brand new DA 42 in Speyer
(EDRY) on 3-4-07 during take off.

It seems, that the battery was down and both engine were started with
remote power.
After take off when retracting the gear, the props feathered and both
engines stopped.

You can read about that accident in German (sorry) in
www.pilotundflugzeug.de

First hearing about that accident and the background, I could not
believe it.

I don't even know where to start. How can an aircraft, that depends on
electrical power for the operation of it's engines, be airworthy without
fully redundant electrical systems? While in this particular case the pilot
might have noticed the problem, had he meticuously follow procedures and
started the second engine at the plane's own power, it is quite easy to find
failure modes that would go unnoticed inflight, yet cause double engine
failure at the instant the gear is lowered on final. Lead batteries are
known to occasionally go flat suddenly, once the buildup of oxide makes
contact between the lead elements. Happened to me in the car once. The
engine (a diesel with mechanical injection pump) ran happily without me even
noticing the failure until I shut it down. When I turned the power back on
again, not even the lights in the dashboard would light up, it was
completely and utterly dead.

I would never have thought that they cut corners like that at Diamond. I
Hope this will not create a lot of mistrust in aerodiesels, as it is not a
diesel issue. I guess you could call it a FADEC issue if you wanted, however
it really is an issue of redundancy of essential systems, and easily
solveable as such.

regards,
Friedrich