Problem with AOA_BAR on EFIS D100

[dynonsupport]

Still pretty stumped. Does it still act exactly as you describe above (AOA is red in cruise, but goes to green some minutes later with no change in real AOA?) Which product of ours is this? You might try a calibration where you don't quite get to the deep break of the stall.

 

[GalinHdz]

Still pretty stumped. Does it still act exactly as you describe above (AOA is red in cruise, but goes to green some minutes later with no change in real AOA?) Which product of ours is this? You might try a calibration where you don't quite get to the deep break of the stall.

Yes it is still doing it. I tried re-calibrating it several times to include the single stall method without the deep stall as you suggested, but no luck. After about 30-45mins it seems to work since I get a full set of green bars. Just in case, I am going to run an entirely new line for the AOA, but I doubt this will do anything. Now, it was sent back for repair last year after going to the "blue screen of death". I had not set up the AOA before I sent it back for repair so I don't know if this problem existed prior to it being repaired.

It is a D6 PN: 101222-000, SN: 1519.

 

[dynonsupport]

So during the actual AOA calibration, the AOA bar is showing something along the lines of the "raw" data, though graphically. As you increase and decrease AOA during the calibration procedure itself, is it responsive?

 

[GalinHdz]

So during the actual AOA calibration, the AOA bar is showing something along the lines of the "raw" data, though graphically. As you increase and decrease AOA during the calibration procedure itself, is it responsive?

What do you mean by "raw" data? The bars show up during the calibration process?

 

[dynonsupport]

What do you mean by "raw" data? The bars show up during the calibration process?

Your normal Forum Tender is taking a break, so the backup Forum Tender must hazard a guess. Restating the reference to "raw data": How responsive are the bars being displayed while you're in the calibration process?

 

[GalinHdz]

What do you mean by "raw" data? The bars show up during the calibration process?

Your normal Forum Tender is taking a break, so the backup Forum Tender must hazard a guess. Restating the reference to "raw data": How responsive are the bars being displayed while you're in the calibration process?

I really wasn't looking at the bars as I did the stall. What am I supposed to see displayed as I stall the airplane? 

 

[GalinHdz]

What do you mean by "raw" data? The bars show up during the calibration process?

Your normal Forum Tender is taking a break, so the backup Forum Tender must hazard a guess. Restating the reference to "raw data": How responsive are the bars being displayed while you're in the calibration process?

I really wasn't looking at the bars as I did the stall. What am I supposed to see displayed as I stall the airplane? 

Am I supposed to see just red bars?

 

[dynonsupport]

Not neccesarily. It should move and be responsive as AOA changes. It might not use the full range of the graph. As a test, go into the calibration procedure and then go between fast cruise and slow flight (no need to stall). As you slow down and speed up (as AOA increases), is the AOA graph changing in a timely fashion? It's not the magnitude of the change that we're interested in here, but the responsiveness.

 

[GalinHdz]

Not neccesarily. It should move and be responsive as AOA changes. It might not use the full range of the graph. As a test, go into the calibration procedure and then go between fast cruise and slow flight (no need to stall). As you slow down and speed up (as AOA increases), is the AOA graph changing in a timely fashion? It's not the magnitude of the change that we're interested in here, but the responsiveness.

I will check it this week-end, see what it does and will post the results. 

 

[GalinHdz]

I did the AOA calibration just after takeoff. I had one red bar and stayed that way with no change. I then flew for another Hr and did the calibration again. This time the bars moved up and down as I did the calibration.

Either way I do the calibration, I only get one red bar until about 45minutes when yellow bars start to appear. After 1:15 all green bars are present and they move as I change the pitch angle.

At 30 Minutes

At 45 Minutes

At 1 Hr

At 1Hr 15Minutes

Sorry about the image quality. 

 

[GalinHdz]

So, any ideas on what to try next?

 

[dynonsupport]

That's starting to sound like a pressure sensor that is somehow oddly sensitive to the amount of time it has been powered on. Doesn't at all make sense, but it may be a hardware thing. When you have some down time, give us a call at 425-402-0433 or email support at dynonavionics dot com to have your unit back here for a look.

 

[GalinHdz]

That's starting to sound like a pressure sensor that is somehow oddly sensitive to the amount of time it has been powered on. Doesn't at all make sense, but it may be a hardware thing. When you have some down time, give us a call at 425-402-0433 or email support at dynonavionics dot com to have your unit back here for a look.

OK. I will call them. Could a leak in the AOA line cause this problem? 

 

[dynonsupport]

If the AOA line was blocked near the pitot (or even in it), with just a very very tiny hole, that might cause what you're seeing. Ie, at the start of a flight, you'd have your formerly static pressure on the Dynon side of the blockage. Then, over the next hour, as the pressure equalizes to the in-flight pressure, you'd see the AOA come alive. So that is a possible explanation. To test - pop your AOA line off the Dynon, and see if you can blow through it from the pitot end. Compare with the pitot line to see the flow you should be expecting.

 

[GalinHdz]

If the AOA line was blocked near the pitot (or even in it), with just a very very tiny hole, that might cause what you're seeing. Ie, at the start of a flight, you'd have your formerly static pressure on the Dynon side of the blockage. Then, over the next hour, as the pressure equalizes to the in-flight pressure, you'd see the AOA come alive. So that is a possible explanation. To test - pop your AOA line off the Dynon, and see if you can blow through it from the pitot end. Compare with the pitot line to see the flow you should be expecting.

OK. I will be gone for 2 weeks so I can't get to it till after April 2nd. I will check that 1st before calling.

 

[GalinHdz]

If the AOA line was blocked near the pitot (or even in it), with just a very very tiny hole, that might cause what you're seeing. Ie, at the start of a flight, you'd have your formerly static pressure on the Dynon side of the blockage. Then, over the next hour, as the pressure equalizes to the in-flight pressure, you'd see the AOA come alive. So that is a possible explanation. To test - pop your AOA line off the Dynon, and see if you can blow through it from the pitot end. Compare with the pitot line to see the flow you should be expecting.

With this in mind I checked the AOA line and found it was exactly as you described it. It was blocked in such a way that only a very very small amount of air was getting through. I couldn't clear it up so I ran an entirely new AOA line.

I took the airplane up today and it calibrated PERFECTLY! It now works exactly as it should and the AOA indication is as I would expect in each segment of the flight envelope.

THANKS for bearing with me and helping me work through this issue until it was solved. You guys are great!