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Stall Warning & AOA

Amadeus

Well Known Member
I just picked up from the paint shop and found that there is no stall horn ("horn" meaning a warning over the headset) or angle-of-attack sounds. AOA does work as the indicator on the G3X screen still displays.

The paint shop would not paint with the wings removed as this was not covered by their insurance policy (they said I would need to remove wings myself when I got home and primer the unpainted area when I put on the gap filler). So logically I assume they did not remove the wings. However I wonder if people there were curious and pulled the wings to take a look and disconnect something. Is that possible?
 
Considering your situation and what might be common to both of those failures. I would consider pulling the left wing off and check the connectors. It is only a 5 minute job to be sure.
 
The AOA audio isn’t electrically tied to the wing connector - it’s coming from your EFIS. If you’re seeing AOA transition on the PFD, that means the AOA tubing is still working as intended. To me, the fact that you’re not getting audio for stall or AOA would point to an audio setting issue. But don’t ask me to explain why it would have worked before paint but not after. Just trying to help you rule out what isn’t the issue.
 
The AOA audio isn’t electrically tied to the wing connector - it’s coming from your EFIS. If you’re seeing AOA transition on the PFD, that means the AOA tubing is still working as intended. To me, the fact that you’re not getting audio for stall or AOA would point to an audio setting issue. But don’t ask me to explain why it would have worked before paint but not after. Just trying to help you rule out what isn’t the issue.

Doesn’t AOA depend on the air line that connects to the special rivet just behind the LE under the left wing? That line has a connector at the root of the wing.
 
Correct, but he’s seeing the AOA transition on his PFD. That means the “plumbing” is ok. The fact he’s not getting audio alerts for either AOA or stall seems to point to a common cause, which points to an EFIS or audio panel issue to me. I’m a Dynon guy, so can’t address a possible G3X issue.
 
Does electronics have capability to test inputs? Perhaps manually operate stall vane switch and see if input changes state on the EFIS.
 
Assuming the G3X logs the same information as the Dynon, the data file will log AOA and stall warning status if you download it to a USB drive.
 
I’d start by taking the inspection cover off and making sure I had power to the stall warning switch. It is a very simple system. Power to switch. Switch to earth.
Interruption at the wing root connector seems a possibility.
Start simple, then go complex.:)
Cheers DaveH
120485
 
Oddity.

Did preflight yesterday and discovered a blown fuse on NAV Strobe. Replaced fuse then checked the Stall "Horn" per normal procedure and it worked! While flying I decided to do a stall to see if still working and found the AOA sounds to be working, also.

Is there some sort of connection there?
 
Oddity, for sure! Did you try pulling the fuse and seeing if it replicated?

Why didn't I think of that?

I did not. I replaced the blown fuse then used the NAV Strobe lights during flight and it did not blow again. Had I thought about it I could've pulled the fuse in flight and performed another stall. Now I have a task for my next trip to the hangar!
 
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