Help! Squawks! Radio noise, AI/vacuum, Skywatch..

[gsengle]

I have a couple of issues with my new (to me) Ovation that maybe someone here have experienced and could provide guidance.

1)  My skywatch system, interfaced into my 530, seems to think that my own aircraft is traffic to be alerted.  I get the TRAFFIC TRAFFIC alert, only to realize the traffic is me, in my location and altitude.  I just discovered the test mode - does this cause the device to detect my own transponder and suppress this alert - was going to add this to my checklist and see if it helped?  Or is this a fault in the equipment?

2)  My 530 com gets lots of ignition noise, to the point of rendering some atc transmissions unreadable, and is just generally annoying.  The old com under it has much less noise.  What can be done to help the 530?

3)  The really big issue.  Yesterday afternoon on a long flight, VFR above a cloud deck I noticed that the King 150 autopilot wasn't tracking very well and had me right of course.  Then I noticed that the AI was starting to slouch off to one side.  So what was happening in nav mode was that the airplane was following the AI off to one side a bit, but then would decide to bank back the other way to stay on course, and these two would balance out and I'd end up level a bit to the side of course.  So, it was obvious what was happening, there was an AI problem.  Checked vacuum and pressure was fine.  But I turned on the electric standby vacuum pump anyway to see if that helped.  This bumped the vacuum pressure a very tiny bit, just enough to make clear the standby was working.  But without standby the vacuum pressure was normal.  So I figured the problem was with the AI not vacuum.  But then surprise surprise, a few mins of both pumps running re-erected the AI.  So I'd turn off the standby, and 5 mins later, same problem.  And again, vacuum gauge showing no issue.  Did this 2-3 times, and the standby helped each time.  So I left the standby running for a half hour.  Turns out weather at my destination was clear again, so I turned off the standby one last time, and this time the AI was fine.  Even stayed level when taxiing back with low-ish pressure from the engine driven pump.  What's going on?

What's scary is how difficult this would have been to detect IMC.  Thinking about backup AI in the one open spot on my panel, recommendations?

thanks in advance for any thoughts or insights!!!

Greg

[jlunseth]

May be the pump, but from the sounds of it, it is the gyro in the AI.  Needs a little extra pressure to work properly.  Bearings going?  Vane(s) stuck?  Sounds like you need an avionics shop, sorry.

[gsengle]

Latest news, vacuum pump died, so I guess I have my answer!

[Kwixdraw]

I found an excellent write up on electrical noise on the Plane Power website in the troubleshooting section. If your Ovation has a music player in it it sounds like a strong candidate for the problem.

[takair]

1.  The Skywatch should get a suppression pulse from the transponder.  If this wire is broken or missing, you will get own ship.  If you have a DME, it too shuold have a suppression line.  You can test this theory by going to standby on the transponder and shutting off the DME (one at a time) to see if own ship goes away.

2.  The article mentioned above may help.  you may also have some bad grounds or shield grounds.  Magneto P leads may have broken shields.  Can you isolate during mag check?  Sounds like you are sure it is not alternator noise. 

3.  Be sure you don't have an open line or kinked line.  The AI relies on airflow, although we read vacuum pressure.  You can have good vacuum and low flow.  I see you had the pump fail, but this could be the result of the above.  Open line could cause junk to get in and fail pump.  Kink could result in reduced flow and cooling.  It is a quick check under the panel for your mechanic when he changes the pump.

Hope this helps.

[gsengle]

Thanks for all the advice - very helpful.  I just got a new pump installed, I'll make sure the line is checked - this seems likely given the symptoms I had leading up to failure...  hmmm...

[Mooney_Allegro]

I have the Skywatch system & after install, the Skywatch would pickup my own ship.  It took my avionics shop a few months to figure it out.  It was caused by the KN64 DME hooked up to the Skywatch system somehow or the GNS530W, I don't remember which one, but the DME was the culprit.  Apparently the hookup instructions are vague, and my avionics installer didn't know about the issue with the DME.  It was VERY frustrating, since this issue lasted for about 3 months for me.

[gsengle]

Would the issue go away when the DME was turned off?

[gsengle]

One mystery kinda solved.  Turns out the suppression circuit only works with the DME turned ON whether I'm using it or not.  Anyone else have this experience?  I'm not going to worry about it - but is this how it should be wired?  AI seems to be fine now after changing pump....

[gsengle]

 

just for fun, from the test flight - yes we do have mountains in the east...

 

[takair]

Quote: gsengle

One mystery kinda solved.  Turns out the suppression circuit only works with the DME turned ON whether I'm using it or not.  Anyone else have this experience?  I'm not going to worry about it - but is this how it should be wired?  AI seems to be fine now after changing pump....