DA42 double engine failure
Julian, just to be pedantic.... quote.. your point of no return is suddenly several miles behind you....
The Point of No-Return will not change, no matter what happens to your aircraft.
Also if it is behind you, then just continue....
.
The Point of No-Return will not change, no matter what happens to your aircraft.
Also if it is behind you, then just continue....
.
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My business designs and manufactures battery monitors for the specialist vehicles and defence applications - we own the IP for the worlds most accurate state of charge and state of health technology. Unless you have a state of health monitor there is no way to check if that battery is flat or f****d. Many batteries are damaged (permanently) with excessive discharge - a jump start being an obvious symptom of excessive discharge. If the DA42 systems are indeed as described here, there’s no way you should attempt to reuse a flattened battery. Accident waiting to happen. What a stupid system - why didn’t they employ a proper electrical engineer to design a sensible fail-safe system?
Most modern batteries are pure lead AGM types - they’ll accept as much current as you can throw at them as long as the voltage is properly regulated.
The only way to accurately monitor battery state of health is to monitor the charge and recharge trend and compare that against the stated capacity of the battery over time. Battery testers (even expensive ohmic ones) don’t work (Enersys the worlds largest battery manufacturer states that battery testers cannot and will not work with their batteries).
FWIW Id only ever fit the Concorde AGM or EnerSys Pure Lead battery in my aircraft..
Most modern batteries are pure lead AGM types - they’ll accept as much current as you can throw at them as long as the voltage is properly regulated.
The only way to accurately monitor battery state of health is to monitor the charge and recharge trend and compare that against the stated capacity of the battery over time. Battery testers (even expensive ohmic ones) don’t work (Enersys the worlds largest battery manufacturer states that battery testers cannot and will not work with their batteries).
FWIW Id only ever fit the Concorde AGM or EnerSys Pure Lead battery in my aircraft..
You can’t engineer ‘stupid’ out of a system.
I worked for a flightschool where we ended up having 4 of these.
MX kept a set of batteries on a trickle charger and we averaged about 1 jumpstart per month as inevitably Master Switches are left on during preflight or postflight inspections.
Never a problem if you follow the instructions
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Keep in mind that what the pilots did was completely against procedures published in the POH.
You can’t engineer ‘stupid’ out of a system.
I worked for a flightschool where we ended up having 4 of these.
MX kept a set of batteries on a trickle charger and we averaged about 1 jumpstart per month as inevitably Master Switches are left on during preflight or postflight inspections.
Never a problem if you follow the instructions
You can’t engineer ‘stupid’ out of a system.
I worked for a flightschool where we ended up having 4 of these.
MX kept a set of batteries on a trickle charger and we averaged about 1 jumpstart per month as inevitably Master Switches are left on during preflight or postflight inspections.
Never a problem if you follow the instructions
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I have been flying a DA-42 recently and am interested in a bit of a follow-up in the intervening years since this accident.
It appears that that this happened in the early days when only Thielert engines were available and it appears that there were no ECU back-up batteries.
Was the solution a retrofit to the Thielert models with ECU back-up batteries or were there other changes?
I fly the Austro-engine versions but they used to be Thielerts. Did the factory-built Austro-engine versions get produced with ECU back-up batteries?
It appears that that this happened in the early days when only Thielert engines were available and it appears that there were no ECU back-up batteries.
Was the solution a retrofit to the Thielert models with ECU back-up batteries or were there other changes?
I fly the Austro-engine versions but they used to be Thielerts. Did the factory-built Austro-engine versions get produced with ECU back-up batteries?
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The Austro DA62s have:
Main Battery
2 x Alternators, each capable of supporting the entire electrical system.
Back up batteries for each ECU system (ie one left and one right).
The wiring schematic is rather busy (page 516 at http://support.diamond-air.at/filead...1-complete.pdf) but clearly there is loads of redundancy. I think the Austro 42s are similar.
Main Battery
2 x Alternators, each capable of supporting the entire electrical system.
Back up batteries for each ECU system (ie one left and one right).
The wiring schematic is rather busy (page 516 at http://support.diamond-air.at/filead...1-complete.pdf) but clearly there is loads of redundancy. I think the Austro 42s are similar.
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Dont use standard trickle chargers on sealed AGM aircraft batteries (i.e. a standard automotive charger).. The ripple voltage and fixed voltage output will damage the battery... needs to be a 3 stage output charger with a Gel/AGM battery setting..
With3Tees
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Hi All,
So looking at the POH for DA42 with TAE-125-02-99 engines, there are ECU backup batteries. I can't seem to determine whether these are something that was added after the double engine failure crash or something that was in place before the crash.
Does anyone know? Was OAM 42-129 in response to the issues that caused the crash?
Thanks
Matt
So looking at the POH for DA42 with TAE-125-02-99 engines, there are ECU backup batteries. I can't seem to determine whether these are something that was added after the double engine failure crash or something that was in place before the crash.
Does anyone know? Was OAM 42-129 in response to the issues that caused the crash?
Thanks
Matt
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Hi All,
So looking at the POH for DA42 with TAE-125-02-99 engines, there are ECU backup batteries. I can't seem to determine whether these are something that was added after the double engine failure crash or something that was in place before the crash.
Does anyone know? Was OAM 42-129 in response to the issues that caused the crash?
Thanks
Matt
So looking at the POH for DA42 with TAE-125-02-99 engines, there are ECU backup batteries. I can't seem to determine whether these are something that was added after the double engine failure crash or something that was in place before the crash.
Does anyone know? Was OAM 42-129 in response to the issues that caused the crash?
Thanks
Matt
These batterys are are time critical items and re-newed as part of the aircraft maintenance program.
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They were added as a result of a crash, if I remember correctly the aircraft involved had a flat battery, they used external power to start an engine, then started the other, there was something in the flight manual re charging the battery etc that was missed by the crew, the aircraft was running ok and they departed, however the battery was in essence still nearly flat but was supplying sufficient power for the instruments and FADEC, upon take off the electric gear was selected up, this drew the available power resulting in the FADEC failing and both engines shutting down resulting in a crash landing, hence the independent power source being added.
