Ragsf15e

So this has happened probably 6 times in 40 hours. Never more than once per flight. I wrote Garmin support to ask about it. There’s no Garmin dealer easily available to me. Here’s what I got back. It seems like they have an idea but want to keep a secret? Frustrating. “Drew, Thank you for contacting Garmin International. What dealer are you working with in your area? If you could have them call in and ask for me and I will be able to direct them on a fix for the issue you are having.” What if I was experimental? I didn’t say i was going to fix it myself regardless of rules? Id just like to understand the nature of the issue before I start a wild goose chase with some dealer I have no relationship with? @PT20J have you had better luck? Drew Best Regards,

I had a similar timing change as @EricJ described after having my mag oh. Recheck timing helped. One other thought is that (maybe) it’s hotter now than when you did this earlier (25 hours ago) and the density altitude is different. Try leaning a little, slightly less than full rich, for your mag check and see if it smooths out. Impossible to hurt anything at that low power setting as long as you don’t run it so long it gets warm chts, so you can play with it a little.

I breezed through the manual, but it seems there are relatively strict testing and/or replacement requirements on your standby battery.

Welcome to MS! Sometimes these kind of intermittent failures are the hardest to solve! The cb may indeed be bad, however, that’s a weird one to fail. Have you tested the gear warning system to see if it works? At altitude, with gear up, pull throttle to idle. You should get a gear warning horn. There’s a switch that activates when the throttle is around 13” or less.

Again, I’m only an internet mechanic, but if the gear actually went up and down as you put the switch up and down, it’s not the airspeed switch. That failing causes the gear not to come up at all. Also, it’s very unlikely that the gear actually hit the airframe, and that would very likely cause a popped gear actuator circuit breaker. So you’re looking at the throttle switch or the limit switches. @PT20J probably has the electrical diagram memorized, but can the limit switches trigger the gear alarm or is it only triggered by the throttle switch? You see, I had this same failure happen (admittedly on a much older F model), and it was fixed with some lps 1 and exercising the throttle switch…

My terribly uneducated guess… throttle gear warning switch. Free on the internet.

Obviously you need a swing check on the ground, and @EricJand @N201MKTurbo are way smarter than me on this, but i think you’d blow the gear actuator cb if the gear hit something short of retraction… I’m guessing you have a different problem… but then I trust the other guys too, so…

However, if you’ve got money available for the potential maintenance (worst case overhaul) and you can reach an acceptable price, you might be just fine. You might get a really nice airplane… just go in with eyes open to the potential costs.

I’m mostly with you on just looking for all the cylinders firing, but it’s probably worth looking at the drops too. You can start to see the timing change over lots of flights. Last annual i had my surefly dropping about 50rpm and its very stable over time. The mag though was only dropping ~20. It was actually hard to see a drop and I was worried that my switch was bad or something. Weird. I told my mechanic I thought it had advanced somehow. He checked the timing and it was somewhere around 3-5 degrees advanced. It didn’t take much to be noticed. Don’t know how/why, maybe just as it wears? I do lean just like you said, very lean on the ground, about halfway to rich for the mag check.

Ha! So it’s one of the screws… @DXB is probably right. Sounds like he’s done it before.

As long as it recovers, it’s the plugs, but if it’s slowly getting a greater rpm drop/spread and not coming back up again, the timing could be slipping as the mag wears. Just throwing that out as an alternative if it’s not the plug (which is pretty easy to id with the engine monitor.

Again, I haven’t tried it but I found a little more info from Btalk. It’s called the trim pot. Upper left screw. Question was, can I adjust it myself? ”Legally? No. But for the STec 30 you remove the upper left screw on the turn coordinator that is the autopilot. Then you stick a very small diameter screw driver into that hole and turn the pot in the direction you want to correct for, in my case counterclockwise. You turn it a little and then give it a minute or so to correct. Repeat as necessary. Don't know how the 55X works.”

Interesting, I haven’t heard that, do you know where that setting is? My stec is slightly off center regardless of mode though- gps, vnav or even heading.

I want to say there’s a screw below/behind the lower left (or maybe right?) mounting screw that is an adjustment.

I have the same set up and mine does that as well. A little less than yours, but very similar. There is an adjustment on the stec, to correct that, but mine is so close that I decided not to touch anything and possibly mess up something else. I think it is a screw to turn in a relatively simple adjustment, but you’ll have to look through the maintenance manual or other installation manual.

Was the power (rpm) pulled back during the event (ie during descent)?

Everything is usually less busy at night and you’re using a long runway. I’d probably just take my time and do stop and goes… I guess I do that so they “count” toward currency. Meaning, come to a complete stop, go through appropriate checklists on the runway to reconfigure (if required), then takeoff again. Not taxi back.

I’ve had the same experience… “fixed” for a while (months at a time) and then not. Sometimes after maintenance, sometimes randomly. It’s definitely weird.

I guess I was thinking first flight of the day, cold, plane sat for two weeks. It starts its fluctuating pretty quickly. Do You just mean that dry bubble in the line that’s always there?

I think as good a guess as any, although mine starts fluctuating within minutes of starting even on really cold days. I’d be surprised if it was hot enough to vaporize.

So I stand corrected, seems you can do it!

I started this, and thought I had mine fixed (unknown why though). It was only about 3 months before fluctuations started again. I’m currently ignoring it until one of us figures out a better fix.

Yeah, tabs (50 gallons) or around 40 is much more flexible. I don’t sweat it on my sealant…

I’m pretty sure you cannot display “adsb in” information from your portable on your ifd, only on your ipad. You need a certified/mounted adsb in to display on the ifd. If you look at the yellow box at the bottom of the slides @midlifeflyer linked, you’ll see that notification.

Nicely done.