430W Connectivity Issues

[40Cal]

My 430w unit started periodically losing GPS connectivity in flight. It was infrequent and temporary as it would typically come back after a few minutes. The avionics guy suspected a bad antenna so we swapped it out for a new one. In the 10 or so flights since then, during 8 flights, the unit locked onto a good signal at start up and maintained it throughout the run up, only to then lose GPS connectivity completely at or within seconds of rotation. Only twice has this not happened. 80% of the time the signal will return about 30 minutes into the flight and won’t drop again. The other 20% of the time, the signal never returns. But after start up the next flight, the whole scenario repeats in the exact same manner and timing. Thoughts???

Thanks in advance!

 

Edited April 27, 2023 by 40Cal
Correct typo

[ArtVandelay]

Electronics don’t last forever, especially when exposed to heat, vibration, and are 20 years old. I’d check antenna connection(s) on the back of the box if they weren’t checked when antenna was replaced.
Otherwise see if shop can bench test it.

[skykrawler]

Your use of 'connectivity' - does that mean 'of the antenna?'  or GPS reception?

There is a page under NAV on the 430 that indicates the satellite reception levels and status.   I suggest operating ONLY the GPS on the ground and observing that display.  Observe someone else's display for comparison.

Then start your other systems and and fly the airplane to determine if there is interference evidenced by a change in the status page.

[carusoam]

How old are the antenna wires…?

Many have been changed to the latest spec for antenna wires… nav/com issues…

GPS signals are as week as signals can be…

So grounding issues have come up a few times…

People have found corrosion growing under the antenna…

Sounds like a project for your local radio guru… looking for signs of things that can interrupt the connections…

Best regards,

-a-

[40Cal]

Thanks for the replies everyone! I took it to the avionics shop and they replaced the connections on both ends—at the antenna and at the back of the unit. I did two flight (one with about 8 touch and goes) and so far no problems, which is the longest stretch since this issue cropped up, so I’m hopeful that was it. Unfortunately, the plane had to go right back into the shop because I all of the sudden got a 300 rpm drop on one mag check that I was unable to clear via standard procedures. Turned out that a lead to the suspicious spark plug was wrapped tightly around the #4 exhaust riser which baked the lead. Picture below. So the shop is installing a new ignition harness. Then, while it was in the shop, the pitot/static company came to do my IFR recert and broke my airspeed indicator during the test. So the airspeed indicator was sent out to be overhauled. ALWAYS something! All of this is to say that I haven’t been able to really put the GPS through the paces just yet but I’m hoping to get the plane back this week. I’ll let you know if the issues resurface. Thanks again for the input! Really appreciate you taking the time! 

[carusoam]

31 minutes ago, 40Cal said:

Thanks for the replies everyone! I took it to the avionics shop and they replaced the connections on both ends—at the antenna and at the back of the unit. I did two flight (one with about 8 touch and goes) and so far no problems, which is the longest stretch since this issue cropped up, so I’m hopeful that was it. Unfortunately, the plane had to go right back into the shop because I all of the sudden got a 300 rpm drop on one mag check that I was unable to clear via standard procedures. Turned out that a lead to the suspicious spark plug was wrapped tightly around the #4 exhaust riser which baked the lead. Picture below. So the shop is installing a new ignition harness. Then, while it was in the shop, the pitot/static company came to do my IFR recert and broke my airspeed indicator during the test. So the airspeed indicator was sent out to be overhauled. ALWAYS something! All of this is to say that I haven’t been able to really put the GPS through the paces just yet but I’m hoping to get the plane back this week. I’ll let you know if the issues resurface. Thanks again for the input! Really appreciate you taking the time! 

Great catch, and pic!

Ooops. It is not normal to have wires contacting the exhaust pipes….

Work with your mechanic to find the proper wire routing for that… or the proper method to hold the wires away from that…

Exhaust gas temps 1500+°F can far exceed the degradation temperature of the most expensive wire insulation…

Be on the lookout for EGT sensor routing as well… they need to be kept separate from spark plug wires, while you are moving things around…

If there were a wire god… he must not have received your tithe… 

Best regards,

-a-

[PT20J]

Wonder how that got past annual inspection?

[40Cal]

Great question, which I will put to the shop that did the annual. 

[skykrawler]

I just saw an Arrow  in annual that had no safety wire on the oil filter and the right wheel was actually loose (the nut/collar had not been tightened correctly).

Luckily, the owner only flew the airplane 14 hrs the past year.