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Alarm that I cannot identify

Strappe

Member
I get an alarm when stationary with engine at about 4100 Rpm, oil temp 125 F, no message. Reduce throttle and it becomes chattery then quits. Same deal on initial take off run, but stops after only a few seconds. Flew an hour with no alarm, then it sounded during roll out after landing.

No visual clue that I can find to tell me what it is. Recently replaced throttle springs and installed new 2020 gps antenna. At first, the backup battery low charge message was present, but it is recharged now and I got the alarm again.

Other suggestions?
 
Skyview or older D180? If it's a Skyview, the RPM makes me wonder if it's the canopy latch alarm.

Not that I know what it sounds like, since I have a D180.
 
I thought that could be it, but would the stall warning go off while stationary and running engine up on ramp?
 
It starts as a steady. high pitched tone, and then becomes beep beep beep beep and stops. If I am stationary and run engine up a bit higher than the 4,000 RPM for ignition check, it remains steady, and quits when I lower RPM. It typically does not come on during landing but does sound briefly during roll out. No lights on panel. I have the display set to show CHT, not coolant temp. Someone here suggested it could be that the coolant temp is too low. That seems unlikely if it also goes off during the roll out after landing after an hour flight.
 
The Skyview logs should reveal the source of the issue. Copy them out to a thumb drive and take a look from your PC.
 
The Skyview logs should reveal the source of the issue. Copy them out to a thumb drive and take a look from your PC.

I was just about to suggest the same thing. Even if it does not point directly to the problem it will allow you to eliminate a bunch of stuff.
 
Thanks for the log suggestion. I tried to find them within Skyview itself and of course, couldn't, but didnl't think about exporting them to an Excel file.

The culprit is the AoA alarm.
AOA_16_16
AOA_16_16
AOA_13_16
AOA_16_16
AOA_01_16
AOA_13_16
AOA_04_16 and so forth.

I cannot find any evidence on the exterior of this used RV-12 that an AoA port has been installed. It is clearly not present on either wing. But the AoA alarm was set to YES. (We're still sorting out this newly acquired -12.) How would the AoA alarm sound if there is no AoA pressure port on the wings (suggesting it isn't installed)?
 
It sounds like the reverse of the AOA. If you have an AOA perhaps miss calibrated. It may be picking up flow from prop and in flight? AOA starts with a slow beep than increases until a steady tone at stall when properly calibrated.
 
If you have AoA configured but no input installed, it's probably going to act pretty squirrelly. There's normally a plastic plug installed in the AoA port, so it will sense whatever pressure it has. That will depend on leakage, ambient pressure, who knows. If it were me, I'd look to be sure it doesn't have the AoA tubing and port installed (which you've already done). If not, I'd disable AoA in the Skyview until the AoA line is installed, if you decide to do so. If unsure, you could pull the left wing out a few inches to verify, it's not difficult. There may even be one or two guys at KMLE that would be happy to help you, if you haven't done it before.
 
The user logs show measured angles of attack. So this plane must have an AoA tube somewhere. Any suggestions re: where else to look for it?
 
The user logs show measured angles of attack. So this plane must have an AoA tube somewhere. Any suggestions re: where else to look for it?

Pull the instrument compartment cover, find the AOA port on the back of the Dynon, follow the tubing.
 
If he has a Skyview unit, the AOA connection port is located on the ADHRS module which is located behind the baggage compartment bulkhead.
 
Bud,

As Dave mentioned above, the AOA probe winds up at the ADAHRS unit, which is behind the baggage bulkhead. The other end, the probe, is nothing more than a chrome rivet located under the leading edge of the wing near the stall warning switch (left wing). The plastic tube coming from the ADAHRS is attached to the back of that rivet. At least, that is the current installation recommendation from Van's.

Some time ago, folks were using a ball inflator needle, like you would fill a football with, as the AOA probe. If that is what you have, it should be also mounted somewhere near the stall warning switch.
 
If I were in your shoes and trying to familiarize with a new airplane and avionics, I would not mess with the AOA installation at all or try to trace any tubing, etc. At this point why take off the rear bulkhead (and maybe have to pull the fuel tank) to check the connection to the ADHRS. Get the noise turned off and enjoy your new plane.

Just turn off AOA audio until you are comfortable with everything else. It doesn't matter if there is tubing present or not or if the red plug is in the ADHRS AOA port. The AOA can be exposed to static pressure without tubing present, in fact the installation manual says that the red plug actually has a small hole in it.

Press buttons 7&8 to enter the setup menu then: SETUP MENU>SYSTEM SETUP>AUDIO SETUP>AOA VOLUME: (0% TO 100%). Set it to 0.

I don't think there is a toggle to turn it off, you can just set it's volume to 0.

This will confirm that the problem actually is the AOA, and if it is you can fly the plane without the annoyance of the beeping tone.

Later, if you want to get the AOA working, determine if there is the tubing and port present on the wing and just do a calibration and set the volume where you want it. Or if there is no AOA connections present, buy the Van's retrofit AOA kit and install it at next annual when you have all the inspection covers off and the wings off.
 
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I agree with Tony. Calibrate the AOA per Dynon's installation manual. Save hardware troubleshooting for later if there still is a problem after AOA calibration. Do NOT disable the AOA. It might save your life some day.
 
We want AoA. We were told we had it. Our next step is to look through the airplane build logs and other documents to see what we can find in them. I can assure everyone that nothing is located on the under surface of the leading edge that would serve as a pressure port for an AoA system, I also do not see the combination pitot and AoA port that Dynon sells for other installations. So I am clearly missing something about this particular airplane.

FYI, the set up menus for the Skyview with ver 15.2 software include an option for choosing YES or NO for audio AoA wranings and for now I have set that to NO. It was set to YES.
 
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More than likely, your AOA port (IF you have one) is not a big probe but rather a single pop rivet head located near the stall warning tab under the left wing's leading edge.
 
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Pull the instrument compartment cover, find the AOA port on the back of the Dynon, follow the tubing.

Sorry, didnt pick up on the fact this is a Skyview. David is right. That makes it a lot harder to get at the end of the tubing, if indeed it is there.

Is it possible to contact the original builder and just ask about the AOA?

If not, how about pulling the wing pins and sliding the wing(s) out a few inches to see if there is tubing?

Basically I agree with Tony. Shut off the distracting noise and figure it out at the next condition inspection. AOA really not necessary in this little airplane, unless you are dragging it into very short strips on a regular basi. JMHO.
 
Remove the inspection cover located near the stall warn vane under the left wing. Look or feel in there to find the small diameter plastic tube connected to a rivet. The rivet is likely the same as those used for the static ports on the sides of the fuselage.
If the AOA is installed but is not working properly, then the most likely cause is that the Dynon needs to be calibrated and setup.
 
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