King KI525A Nav flag won't go away

[Geoff]

Hello oh wise Mooney Spacers.  Here's the issue, I'm running a full KFC 200/430 combo and was tooling along the other day  when the nav flag on my KI 525A floped down.  I was hand flying (in VMC) so no real problem, but I wanted to do some diagnosis...

I dialed in a GPS destination on the 430W and made sure I was on "GPS" on the box, but the nav flag was still there.  The needle was giving good indication and was pointing in the right direction.  I coupled the AP in GPS mode and it followed the course.

I then dialed in a local VOR and made sure I was on the "VOR" mode on the 430, nav flag still visible and did the AP thing again and it tracked just fine.

Obviously, I wouldn't trust the thing in IMC.  Any ideas on what could be wrong?

[MARZ]

Any work done recently?  Radio pulled reinserted?  The flag gets a signal through a dedicated wire from the radio.  I would look for something obvious there - but would get your friendly avionics specialist looking into it in any case.

[jlunseth]

I have the same set up except for the addition of roll steering.  I had a couple of weird flaky things going on with the AP when I first got it, all tracked down to connections going bad/getting dirty or corroded.  I had the Nav flag drop and had wild course variations in slaved mode.  That was caused by a poor connection in the wing somewhere, between the flux gate and the HSI.  I had the AP shutting off - not disconnecting, which would be annunciated so you would have some warning - but just going dark.  That was caused by a bad switch in the yoke, don't remember if it was the CWS or the trim switch. 

Best bet is to take it to an electronics shop and have them diagnose the fault. 

My AP is all fixed up and working well.  I love it.  I had an Icarus unit installed which supplies roll steering from the 430AW to the AP in HDG mode (with the Icarus switched on).  That allows the AP to use the 430 to fly to and intercept the final approach course for an ILS or LPV.  Then I put it in APPCH mode, it will couple to the glideslope and fly right down it.  Does a very nice job and is teaching me what a smoothly flown approach feels like.  Get it fixed you will love it.

The one good thing about having your AP do something flaky is that it teaches you to watch the annunciator and to look at the 430 every once in awhile just to make sure the AP is giving you what you want.