Shawn26

That is something that I can ask my avionic shop.

This is my third time using Arrow Accessories for the magneto repair. I never had issues with their service. I know QAA also repair Bendix Dual mag. Beside these two I don’t know any other shop! Who did you use for your magneto?

I received good news yesterday from the Avionics Shop. Last week, we removed the magneto and sent it to the mag shop for another inspection. They replaced the contact and bearing, both of which were already replaced during the 500-hour inspection. I reached out to Savvy Aviation for advice, and they confirmed that the only likely source of the erratic RPM readings (based on the P-lead signal) was the magneto creating an arc from the point, bearing and conatct. The mag shop recommended reinstalling the magneto, and if the issue persisted, they offered to build a new magneto from scratch to help rule out potential causes during the troubleshooting process. After reinstalling the magneto, the problem remained. The Avionics Shop, frustrated after chasing the issue for so long, decided to install a new Garmin GEA24B. The erratic RPM readings disappeared and we have a good reading. According to Garmin, the GEA24B has better noise filtration than my previous GEA24A. I haven't picked up the airplane yet, but I trust their diagnosis. This process was extremely time consuming, labor-intensive, and expensive. My main concern is what will happen during the next 500-hour inspection. If I receive a noisier magneto, I’m not sure if the GEA24B will be able to filter out the distortion, potentially putting us back to square one. It's something to consider for the future.

You're absolutely right, and I'm tired of it too. We're taking two steps to troubleshoot the issue. If these don't work, I'll go that route. Replacing the old GEA24 with a new version to see if the problem persists. Reinstalling a newly rebuilt magneto. Hopefuly one will work!

I know that JPI has a sensor, and I believe I had one prior to installing my new avionics. Unfortunately, the Garmin G3X is only certified with the P-lead for the bendix dual mag. So im out of options and I’d prefer not to reinstall the JPI just to resolve this issue.

I presented this option to the avionics shop, but they responded that the system is working, despite some arcing and distortion. Installing a secondary RPM and tachometer is not ideal. There are plenty of airplanes with the same dual magneto setup that have no issues. Recently, Garmin has received numerous inquiries about erratic RPM readings related to P-lead installation on dual magneto systems, and I believe they are working on a solution soon.

Absolutely! A little luck is all I need.

Besides becoming increasingly expensive due to labor and diagnostics, there has been no update. We removed the new 500-hour magneto, sent it to the shop, and they replaced the bearing and contacts components that had already been serviced at 500 hours. We then reinstalled it on the airplane, but there was no change, RPM still erratic. We replaced the entire P-lead wires, but still, no change. The next step is to rebuild a new magneto and install it. I’ve come across a few others on social media with the same issue with the dual mag. This situation is becoming really frustrating, as I've been grounded for about three months. Let me know if you want any further refinements!

I sent you DM. Wondering if you can contact me. Thank you

No, the Mooney it’s not turbo charge. I’ve IO-360.

I believe your engine information EIS works the same exact way as my setup. You don’t have a separate sensor for tac / RPM and the P-lead is the only source of information for your dual mag. You may come across of the same issue I’ve encounter. i just hope Garmin can figure out the problem and provide alternative solution really soon.

I don’t know the UMA part number, but they have one for D-3000 magneto for none certified aircraft. UMA tech-support mentioned they are lots of people using it on certified aircraft, he didn’t know how. Obviously Garmin is not supporting it or provide any guidance on installation. I dropped off the airplane at my Avionic shop. If I get any update on the progress I’ll repost about it. I’m down two months. obviously, I’m not happy about it. We just have to see whats causing this interfering. I’m sure Garmin knows about this issue as I’m not the only one!

My setup was working fine till the mag was removed for 500hrs inspection. I did everything you done! No changes. Unfortunately with D-3000, P-lead is the only source for getting TAC and RPM. I wish UMA would have made RPM sensor for the dual mag for certified aircraft. JPI makes one, and it’s the most reliable and precise way to get the information from the magneto. UMA have one for none certified aircraft for D-3000. I spoke to their technician and I was told many shop install them on certified aircraft but that’s not the route I like to take. I guess we have to stick to the P-lead for now and figure out what needs to be done! My shop suggested to change to new GEA24 version as advised by Garmin. I doubt that solve the problem! Please update if you come across of new information. Thank you.

I came a cross Continental service bulletin for the bendix d-3000 ( SB651 ) I got to look in to it.

If you figure it out, please keep me informed.