Marc Taylor

I had the latest Garmin software installed (G500txi, G5, GFC500, GTN750xi) then flew over 11 hours last week. Around 30 minutes in, small but noticeable oscillation began. About a month out of a “Mooney” shop annual with instructions to check all controls for binding and lubrication. The flight was about 2 hours and the oscillation continued for the rest of the flight. Next flight was 1 hour, oscillation began about 30 minutes in, although the LPV approach was spot on. Tried to find some TriFlow, no luck, but bought a small squeeze bottle of 3 in 1 dry lube. Next flight was 4.6 hours. Between 30 and 40 minutes the oscillation began again. Lubed the both columns with the dry lube, no oscillation the rest of that flight which was rather turbulent. Next flight was 4.3 hours, same thing-about 30 minutes the oscillation started, lubed the columns, no oscillation, LNV smooth as glass. The servos are in the replacement group, so I don’t know if the servos lose strength, if the columns are gumming up or if there is something that overloads the software, or?

Rather surprised on several references to the first flight after their avionics upgrade. The technician that did the first upgrade was in the right seat when we flew after the upgrade, which included several approaches. Following the most recent upgrade, (different shop, the first tech went to work for a known avionics manufacturer and closed his shop) the current avionics shop of choice for me had a Mooney experienced pilot fly the plane for about 1.5 hours. Prior to picking the plane up, the shop owner told me to expect to fly with him before they released the Mooney. About another 1.5 hours, demonstrating what the new avionics capabilities are. The technician that did the installation has 15 years as Mooney technician. The install was on time and on estimate. This link is from AvWeb regarding retro’s. https://www.avweb.com/ownership/retrofit-checklists-test-flying-familiarity/

Follow up to previous post. To get the autopilot to operate completely smooth, it required lubricating the trim wheel bearing. Removed the cover, used Deep Creep to clean and lube. (Short term fix until I can get the proper lubrication completed.) You will feel a noticeable difference. So far, operates very smooth, no oscillation. Even reduced oscillation when climbing in the IAS mode. Visited with the installer-he has had several other brands of aircraft that required extensive work on the elevator/trim to get the oscillation stopped. One airplane trim/elevator required two reworks to get the “stickiness” fixed.

Don What lubricants are you using? I have heard several different recommendations for the yoke and control hinges. thank you

I have a G5, G500txi, GTNxi (4) servos installed in my 252. It started oscillating some time ago. Several trips to the shop, sent the information off the G5 card to Garmin and still no cure. I finally realized the ball was just a tick or two from centering up. Tweaked the trailing edge of the tail, ball centered up and yesterday, no oscillation could be felt. A couple of hunts when making abrupt altitude changes, but then centered up. Occasionally I could see a movement in the G5 & G500txi altitude window (maybe 5 feet), but could not feel it in the yoke or the ride. Probably turbulence. I only flew a little over an hour, so the real test will be a long cross country, but I flew in both heading and Nav (GPS). Also VNAV and RNAV approach. If I had not seen this with my own eyes, I would not believe it would make that much difference. Hopefully, this is the cure, but I will report back when I get a chance to complete a longer flight.

Just make sure your fuel gauges work through out the range of the gauge. If you get a call from the FAA, they will make a point the aircraft does not meet flight standards if the fuel gauges fail to indicate the fuel quantity should the subject come up. They didn’t get too nasty because the other wing had enough fuel and correct indication for the completion of the flight, but said the plane should have been grounded where I had made a precautionary landing. There had been two occasions where techs were working in the area of the sender and the right wing was showing 3/4 tank of fuel.

When a friend upgraded his panel, the shop I work with said the G3X is very Garmin specific, meaning it does not play well with other brands. I was advised if I have a G500txi, the extra features of the G5 vs. the GI275 would not be worth the investment. However, if you are keeping the KAP150 autopilot, then the question becomes what is needed to drive it? My 252 is some distance away getting an annual, so I do not have access to my log books. I previously had a G500 and the logs would show which adapters were used for the 150 (I updated to the GFC500 autopilot-the G5 drives it). The best advice I can offer is, if possible, work with a shop that has experience with your airplane and the avionics you want to install. I have had 3 significant updates done on my 252-one took 3 times the estimated time (his first install in a Mooney). The last two have been on time and at the estimate or less. The installer that has done the last two updates have techs that have brand experience (the guy that works on mine was a Mooney mechanic for 15 years previous to becoming an avionics tech).

I had the dealer update the my Garmin software last week. I asked if they felt I should trade the G5 for a GI275. The recommendation was no-you have a G500txi and would not use the features-but, if you didn’t have a G500, then the 275 has tremendous features as described in a previous post. I believe the confusion in one of the previous posts was because when Garmin first released the GI275, it would not interface (drive) the GFC500 autopilot. But, that feature was added with software updates at some point. The only negative I have heard is if someone installs only one GI275 with many of the features offered, the screen gets rather busy.

Had a fluctuating fuel flow indication on my 252. Was at the avionics shop for software updates to the Garmins and mentioned it to the tech. When I was ready to leave, the tech said he had fixed the problem-it was a connection issue-don’t recall if it was a sensor grounding or an intermittent connection. Anyway, it was simple and quick.

What is the correct set up for the single flap? My service manual only refers to the 2 flaps the earlier K's had. Looks like I need to replace the motor and would like to have it set up correctly.

Call Don Maxwell-he may be able to rebuild the cartridge. My vacuum operated brakes finally would not deploy. Service tech siliconed the holes in the boots up, lasted about 4 flights. Rebuilt the cartridges and about 3 pounds or less will deploy the brakes. Much cheaper than the electric, although I could deep six the vacuum pump if I had converted to the electric-my panel is all glass now.

I had my 252 at the installer last week. Avionics is his business. He had a Beech that did what you are describing. They found the controls were binding slightly. My GFC500 would hunt when I made a rapid change in IAS on climb. However, seems like that went away with the last software update-or maybe I am less aggressive with the change?