DA 42 accident

Karl-Heinz Kuenzel wrote:
I did not believe it either. Maybe I am getting to old. For me a
diesel would run forever until you cut the fuel.

not with a common rail fuel supply. The injectors won't open without power.

The main point as far as I'm concerned is, that this is not a particular
problem of the thielert or aerodiesels in general, it's a problem you get
with engines depending on electrical power. This dependancy on electricity
is somehow the price you pay for better fuel efficiency, more comfort and,
as far as the engine itself is concerned, less "finger problems" and
therefore more reliability. As the article itself states, it is not a big
issue to create a redundant system that will eliminate the risk of a single
point electrical failure shutting down an engine, let alone both.

What those people did. They just started #1 and #2 (which was NOT ok)
on external power. And everything looked ok. Until they retracted the
landing gear....

I posted that story in our German newsgroup and nobody seemed to be
interested in that issue. I was just curious, if someone here is
interested.

I'm not a pilot, though I enjoy flying in small aircraft and I have some
technical interest in aviation. As a development engineer in automotive I
particularly like to learn about aeroengines and I somewhat follow the
development of the aerodiesels. I'm mainly lurking here...

regards,
Friedrich

Recently, Friedrich Ostertag posted:

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.

I have a somewhat different take on this event. It appears to me that the
pilot didn't sufficiently understand his aircraft or the implications of
the symptoms he observed. Knowing that there was insufficient power to
start the engines, that the engine & prop controls were dependent on
electric power and that the landing gear used an electric motor would have
stopped me from taking off until the battery/electrical system problem was
addressed. I don't find it surprising that the props feathered in this
situation, and would even say that it would be the expected behavior,
rather than a fluke of some kind. I would find it surprising if Diamond
doesn't have adequate information about their flight systems in the POH to
inform the pilot of this possibility.

Regards,

Neil

On Apr 23, 12:51 pm, "Neil Gould" wrote:
Recently, Friedrich Ostertag posted:



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.

I have a somewhat different take on this event. It appears to me that the
pilot didn't sufficiently understand his aircraft or the implications of
the symptoms he observed. Knowing that there was insufficient power to
start the engines, that the engine & prop controls were dependent on
electric power and that the landing gear used an electric motor would have
stopped me from taking off until the battery/electrical system problem was
addressed. I don't find it surprising that the props feathered in this
situation, and would even say that it would be the expected behavior,
rather than a fluke of some kind. I would find it surprising if Diamond
doesn't have adequate information about their flight systems in the POH to
inform the pilot of this possibility.

Regards,

Neil

I just received an e-mail today from Diamond explaining the situation.
Since the engines are FADEC controlled, the dead battery did not have
enough power to retract the landing gear and keep the engines going.
The e-mail also stated that Diamond is looking into making some
changes.

Cary (DA42 owner)

Recently, Cary posted:

I just received an e-mail today from Diamond explaining the situation.
Since the engines are FADEC controlled, the dead battery did not have
enough power to retract the landing gear and keep the engines going.
The e-mail also stated that Diamond is looking into making some
changes.

Cary (DA42 owner)

The actual wording of that email would be interesting. I'd think that the
FADEC keeps the fuel flow and props configured, and that the current draw
of the landing gear motor(s) probably shut the FADEC down due to low
voltage. While that could be addressed with a different power
configuration (a separate battery for the FADEC, for example), it may also
introduce more failure modes and more factors to take into consideration
during pre-flight.

Neil (NOT a DA42 owner)

"Neil Gould" wrote in message
.. .
Recently, Cary posted:

I just received an e-mail today from Diamond explaining the situation.
Since the engines are FADEC controlled, the dead battery did not have
enough power to retract the landing gear and keep the engines going.
The e-mail also stated that Diamond is looking into making some
changes.

Cary (DA42 owner)

The actual wording of that email would be interesting. I'd think that the
FADEC keeps the fuel flow and props configured, and that the current draw
of the landing gear motor(s) probably shut the FADEC down due to low
voltage. While that could be addressed with a different power
configuration (a separate battery for the FADEC, for example), it may also
introduce more failure modes and more factors to take into consideration
during pre-flight.

Neil (NOT a DA42 owner)


I have to admit that I am a little surprised that (or if) they did not
include a little magneto/generator in/on each engine, sufficient to power
the FADEC and pumps, to prevent the sort of incident described.

OTOH, I am trying to remember whether larger aircraft systems behave in a
similar way, and I must admit that I do not recall.

In any case, it is very interesting and most unfortunate for those involved,
and we will all know a lot more is the investigation progresses; and a lot
of what we learn will be equally applicable to FADEC equipped spark ignition
engines. It will obviously be worth the effort, over the longer term, since
fuel savings translate readily into payload and range--which is usually
worth more than the fuel savings.

Peter

The message came as a PDF file. I don't think I can post such a file
to the newsgroup, so if you would like to see the file, let me know
where to send it.

Cary

On Apr 23, 1:28 pm, "Neil Gould" wrote:
Recently, Cary posted:

I just received an e-mail today from Diamond explaining the situation.
Since the engines are FADEC controlled, the dead battery did not have
enough power to retract the landing gear and keep the engines going.
The e-mail also stated that Diamond is looking into making some
changes.

Cary (DA42 owner)

The actual wording of that email would be interesting. I'd think that the
FADEC keeps the fuel flow and props configured, and that the current draw
of the landing gear motor(s) probably shut the FADEC down due to low
voltage. While that could be addressed with a different power
configuration (a separate battery for the FADEC, for example), it may also
introduce more failure modes and more factors to take into consideration
during pre-flight.

Neil (NOT a DA42 owner)

Neil Gould schrieb:
Recently, Friedrich Ostertag posted:

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.

I have a somewhat different take on this event. It appears to me that the
pilot didn't sufficiently understand his aircraft or the implications of
the symptoms he observed. Knowing that there was insufficient power to
start the engines, that the engine & prop controls were dependent on
electric power and that the landing gear used an electric motor would have
stopped me from taking off until the battery/electrical system problem was
addressed. I don't find it surprising that the props feathered in this
situation, and would even say that it would be the expected behavior,
rather than a fluke of some kind. I would find it surprising if Diamond
doesn't have adequate information about their flight systems in the POH to
inform the pilot of this possibility.

Regards,

Neil




OK Neil.

You find it in the article.

POH - Under - abnormal operating procedures - 4B.7 STARTING ENGINE WITH
EXTERNAL POWER - #13 Opposite engine ..... START WITH NORMAL PROCEDURE

That is it.

Karl

Recently, Karl-Heinz Kuenzel posted:

Neil Gould schrieb:
I have a somewhat different take on this event. [...]
I don't find it
surprising that the props feathered in this situation, and would
even say that it would be the expected behavior, rather than a fluke
of some kind. I would find it surprising if Diamond doesn't have
adequate information about their flight systems in the POH to inform
the pilot of this possibility.


OK Neil.

You find it in the article.

My Deutsch is far too rusty to find it in the article. ;-)

POH - Under - abnormal operating procedures - 4B.7 STARTING ENGINE
WITH EXTERNAL POWER - #13 Opposite engine ..... START WITH NORMAL
PROCEDURE

That is it.

That's fine for starting the engines, but that isn't the only issue, is
it?

Is there nothing in the POH about the electrically powered items (landing
gear, FADEC, etc.)? If there is, it shouldn't require an EE degree to
realize that one should be concerned about the condition of the batteries,
charging, etc. if one has to "jump start" the engine, or to realize that
something critical is in need of attention.

Maybe I'm just an overly cautious type. ;-)

Neil

Neil Gould wrote:
Recently, Karl-Heinz Kuenzel posted:

Neil Gould schrieb:
I have a somewhat different take on this event. [...]
I don't find it
surprising that the props feathered in this situation, and would
even say that it would be the expected behavior, rather than a fluke
of some kind. I would find it surprising if Diamond doesn't have
adequate information about their flight systems in the POH to inform
the pilot of this possibility.


OK Neil.

You find it in the article.

My Deutsch is far too rusty to find it in the article. ;-)

POH - Under - abnormal operating procedures - 4B.7 STARTING ENGINE
WITH EXTERNAL POWER - #13 Opposite engine ..... START WITH NORMAL
PROCEDURE

That is it.

That's fine for starting the engines, but that isn't the only issue,
is it?

Is there nothing in the POH about the electrically powered items
(landing gear, FADEC, etc.)? If there is, it shouldn't require an EE
degree to realize that one should be concerned about the condition of
the batteries, charging, etc. if one has to "jump start" the engine,
or to realize that something critical is in need of attention.

Maybe I'm just an overly cautious type. ;-)

Neil

I agree that if you are flying what is basically an all electric aircraft
and you have an electrical problem on the ground that you should take extra
care before flight BUT, there should be some system in place that doesn't
allow the gear switch, landing lights or any other electrically operated
item to become an OFF switch with out some damn significant warning.

On 2007-04-23 11:20:24 -0700, "Neil Gould" said:

Recently, Karl-Heinz Kuenzel posted:

Neil Gould schrieb:
I have a somewhat different take on this event. [...]
I don't find it
surprising that the props feathered in this situation, and would
even say that it would be the expected behavior, rather than a fluke
of some kind. I would find it surprising if Diamond doesn't have
adequate information about their flight systems in the POH to inform
the pilot of this possibility.


OK Neil.

You find it in the article.

My Deutsch is far too rusty to find it in the article. ;-)

POH - Under - abnormal operating procedures - 4B.7 STARTING ENGINE
WITH EXTERNAL POWER - #13 Opposite engine ..... START WITH NORMAL
PROCEDURE

That is it.

That's fine for starting the engines, but that isn't the only issue, is
it?

Is there nothing in the POH about the electrically powered items (landing
gear, FADEC, etc.)? If there is, it shouldn't require an EE degree to
realize that one should be concerned about the condition of the batteries,
charging, etc. if one has to "jump start" the engine, or to realize that
something critical is in need of attention.

Maybe I'm just an overly cautious type. ;-)

Neil

No, you are not overly cautious. Every pilot should be taught that if
the battery is dead and you start the plane with external power, the
first thing you check is to see if the alternator(s) is charging. If it
isn't, either the alternator is broken or the battery did not excite
the alternator.

Now, if the excitation system did not excite the alternator, why didn't
the remote starting system do it? It should have. I would want a look
at the power cart, its cables, and the wiring to the port on the
airplane. In fact, especially the latter, as it could provide a clue as
to why the excitation battery died in the first place.
--
Waddling Eagle
World Famous Flight Instructor