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DA40 NG Anomaly

Posted: Tue Dec 04, 2018 2:41 pm
by Mdm0515
Hi - first post here and this seemed like a good place to share this experience.

I'm a relatively new PPL with about 160 total hours, 1/2 of which is post certificate. All of my flying has been in some version of a DA40. I think I've flown 5 of them. On a recent rental with a brand new (100 TT) DA40 NG I was ~10 minutes out from my origin airport on cruise climb at 85% power through 3500' towards 8000' on a perfect VFR morning when I heard a big bang up front with a parallel and immediate pitch down attitude and power reduction. Fearing a total power loss I began to look for a landing spot. Within 30 seconds or so i realized the engine was still running, but laboring. Both ECU A and ECU B FAIL alerts lit up on the PFD and I also received an audible alert. I had flown this airplane 4 times previously

I never actually lost power but the engine would thereafter not advance power past 45%. Realizing I had a good shot of making it back to my origin airport about 8-9 miles away I made the turn and announced my situation to the tower. I repeatedly tried to advance power but it would never exceed 45%. Made it back safe and sound

The diagnosis thus far is vague. It looks like an intake line after the turbo came loose and caused air to escape. But there's no real indication as to why. To repeat the above, this is a brand new airplane and all parts are stock. It's been reported to Diamond but I've heard nothing back

I'm acutely interested in the feedback because I have a DA40 NG on order for late spring 2019 delivery.

I just thought I'd raise awareness

Re: DA40 NG Anomaly

Posted: Tue Dec 04, 2018 4:52 pm
by Don
By spring of next year, Diamond should be producing new Stars with the bullet proof Lycombing engine again.
Just something to consider.

Re: DA40 NG Anomaly

Posted: Tue Dec 04, 2018 11:00 pm
by ZAV
I don’t have any advice on your problem but there have been a number of posts and reports of ECU failures. I personally looked into the DA40 NG and just couldn’t quite feel good about the engine long term. I didn’t like the idea of an ECU failure with loss of power and being unable to troubleshoot the issue in the air.

If there’s a problem in the Lycoming version, you may still be able to generate power to get to a safe spot to land. You might kill your engine but I would choose that over no power and an uncontrolled landing.

Re: DA40 NG Anomaly

Posted: Tue Dec 04, 2018 11:36 pm
by nrenno
I agree with Don, get a DA40 with a bullet proof Lycoming engine. Nothing beats it in terms of simplicity, reliability and safety. Ask any unbiased mechanic that have worked on both engines.

Re: DA40 NG Anomaly

Posted: Wed Dec 05, 2018 2:15 am
by Steven
No experience with the DA40 NG to provide, but good job on handling the emergency safely.

Re: DA40 NG Anomaly

Posted: Wed Dec 05, 2018 11:13 am
by krellis
Agree on the reliability of the IO-360-M1B. I've had two DA40's. My neighbors DA40 has about 3500 hours on the original engine, still good compression, not making metal, good boroscope. Hard to beat that.

I think Diamond made a huge mistake hanging that cast iron MB engine on the front of a previously nicely balanced airplane.

Re: DA40 NG Anomaly

Posted: Wed Dec 05, 2018 8:06 pm
by helidoc67
I have had my Da 40NG since 2013, after about two years I was about to take off, the run up had gone fine , but as I added power I could not get it to advance above 25-30% load; Take off abandoned and taxied back to hangar unable to generate any power above 30%.
Called my service center and they found hose attached to turbo charger had popped off.
Wonder if this happened to you in the air?

Re: DA40 NG Anomaly

Posted: Wed Dec 05, 2018 9:01 pm
by CFIDave
Mdm0515 wrote:The diagnosis thus far is vague. It looks like an intake line after the turbo came loose and caused air to escape. But there's no real indication as to why. To repeat the above, this is a brand new airplane and all parts are stock.
I looked into this and can confirm that if the big air hose that runs from the exit of the intercooler to the engine's intake manifold came off, the aircraft will no longer receive pressurized air from the turbo, resulting in partial power loss.

For redundancy, there are a pair of hose clamps (worm drive clamps) where the hose attaches to a plastic manifold to the engine intake, and another pair of clamps on the other end of the same hose joining the intercooler. If these clamps are properly tightened and safety wired, the hose can't come off. Might the aircraft you flew not have had all of its clamps safety-wired? If so, other DA40 NG owners might want to make a quick inspection of this, easily visible on the big hose on top of the engine.

Looking at the DA40 NG AMM Chapter 81, the latest version from Sept 2017 added this change:
"Note: All hose clamp connections (except such secured with self locking nuts) in the charge air system must be secured with lock wire."

Unless the hose was damaged, the good news is that it should be fixable by just re-attaching everything and properly safety-wiring the worm drive clamps so they can't come loose.

Re: DA40 NG Anomaly

Posted: Wed Dec 05, 2018 11:06 pm
by helidoc67
That is exactly how they fixed my issue, with safety wire; no recurrences.

Is that new afm (amm) available online?

Re: DA40 NG Anomaly

Posted: Thu Dec 06, 2018 3:30 am
by Karl
The terminology used on the G1000 is somewhat misleading. An ECU failure is not what it says it is.
Basically an ECU fail warning is a caution that the ECU sensors have detected an anomaly, in this case low manifold pressure. Both the Austro and TAE powered DA40 will generally be able to maintain altitude with a loss of MAP. Certainly the TAE powered version will maintain altitude with 2 POB and full fuel including long range tanks.

This incident seems to be a simple case of someone not fitting the induction hose clamp tight enough.

Of course if the induction hose came off of an IO series Lycoming you would have a similar loss of power.