40Cal

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

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!

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!

And yes, he had to disconnect the hose in order to install the alternator belt. Must have gotten distracted putting it all back together.

Yes, that nut. And yes, he applied the torque seal this time, right after realizing that’s what happened and tightening it.

Ok, turned out to be a very easy fix. The nut that connects the prop oil line hadn’t been tightened down (to the point that it could still be tightened by hand). The prop seal is brand new and seems to be fine. A few turns of the wrench to tighten it down was all it took. Did another short maintenance flight afterwards and everything seems to be ok. Will definitely keep an eye on it, but very relieved that it was such an easy fix. Definitely a sickening feeling to see that much oil on the outside of the plane! Thanks again to everyone for the input. Happy to join the group!

Thanks for all the great feedback everyone! What a group! The mechanic is going to fly over to my home airport today to check it out. It’s too much oil for me to feel comfortable flying it back to his shop, even though it’s not very far. I’ll let you know what it turns out to be. Hopefully something simple and cheap! (If it is something he did—which seems likely given it happened on the first flight out of maintenance—there will be no charge. If it’s something else…)

I just got my 1964 M20C back from the mechanic: new sky tech starter, plane power alternator to replace the old generator, and an oil change. On the short flight back to my home base I noticed oil mist on the windshield. When I landed this is what I found (pics below). Thoughts? They had to pull the prop to install the belt on the alternator so maybe a bad seal? Not a very mechanical guy, so hoping to take advantage of the community expertise. New to the forum, btw. First post.