Newbie Question 8 - Open Emergency Windows for ECU?

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nworthin
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Newbie Question 8 - Open Emergency Windows for ECU?

Post by nworthin »

In my transition training, I was told to open the emergency windows before performing the ECU tests. The rationale was that an important sensor for the ECU test is located in the rear cabin behind the bulkhead and any pressure differential could cause an ECU "failure" during testing.

So now, I dutifully open the windows before doing the test. Not a big deal but does anyone have any insight into this recommendation or whether it might be another of those "old pilots tales" so common in aviation?
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MackAttack
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by MackAttack »

That sounds very odd to me. That was not the case in my ME training in a 42-VI for example.
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jast
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by jast »

Never heard of this. Which sensor should it be? “Opening a windows” sounds like air pressure. But this is certainly not taken from the inside of the plane..
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michael.g.miller
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by michael.g.miller »

Not eligible to talk about the DA62, but on the 42NG with Austro engines, the window position should not effect the ECU run up. If it does, you need to get it checked out by an experienced Austro mechanic.
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spr
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by spr »

I was taught to open this window during the ECU run up if the air conditioner was on for my 40NG, to avoid an ECU failure annunciation. But I don’t remember the reasoning behind this.
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nworthin
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by nworthin »

spr wrote: Sun Jul 24, 2022 12:33 am I was taught to open this window during the ECU run up if the air conditioner was on for my 40NG, to avoid an ECU failure annunciation. But I don’t remember the reasoning behind this.
Interesting, so maybe there's something to this.

I do have an A/C in my plane and it's typically running when I perform the ECU test.

The compressor unit for the A/C is in the rear of the plane, behind the rear bulkhead. Something about pressure diffrential maybe? Good question for Diamond tech support.
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by chili4way »

It's a DA40NG practice. The ECU is under the pilot seat and the RACC fan on high can create enough of a pressure differential between inside and outside to trip up the ECU during self test/runnup. Opening up the window during runnup solves this, as would turning off the AC. Twins have the ECUs in the engine nacelles.
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nworthin
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by nworthin »

chili4way wrote: Mon Jul 25, 2022 11:09 am It's a DA40NG practice. The ECU is under the pilot seat and the RACC fan on high can create enough of a pressure differential between inside and outside to trip up the ECU during self test/runnup. Opening up the window during runnup solves this, as would turning off the AC. Twins have the ECUs in the engine nacelles.
So, for the DA62 (and DA42), disregard?

It's interesting how these "kernel of truth" items get passed around as universal fact....
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chili4way
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by chili4way »

Yes, disregard for the DA42 and DA62.
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Boatguy
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Re: Newbie Question 8 - Open Emergency Windows for ECU?

Post by Boatguy »

It was not part of my DA62 training.
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