PT20J

It’s OK. A lot of threads would be shorter if we all wrote what we actually meant.

I believe @gevertex’s explanation is correct. The normal communication path between the GDU and the GSU 25D is CAN bus and the RS-232 is a backup path. The single GSU 25D limitation for a certified system is in the installation manual. I don’t have the most current version, but here’s a page from an old one. As Garmin is wont to say, this doesn’t mean that you cannot do it - it just means that you cannot use their STC as the approval basis.

I’m sure you are correct. I should have said LED bulbs rather than just LEDs in my last sentence.

True, but I was responding to @hais question about the G3X

I put those in all my path lights and one by one they went bad over 5 years. I switched them out for Kichler bulbs I got at Home Depot which are a lot more expensive, but none have failed. I don’t know who makes Kichler’s bulbs, but apparently there is a difference in quality between LED manufacturers.

I chose my shop carefully and had multiple quotes. This shop’s price was in the middle. But I know the installer well. He has an A&P/IA but has been doing avionics exclusively for 40+ years. I wrote a detailed specification for what I wanted including options and configuration and I visited the shop once a week to answer any questions and check. It actually too 7.5 calendar weeks to do the job. These things are not easy to work on, and you run into little surprises.

All this reminds me of one day when I was in the light bulb aisle of a hardware store and a bewildered elderly woman exclaimed with a note of resignation, “All I want is a sixty watt light bulb.”

Do you keep a card in the G3X for data logging? Having a card in the GTN is required per the limitations section of the AFMS so it’s technically a violation of FAR 91.9 not to have it although it would have to be a very thorough ramp check to notice that

Pretty close. Labor was 286 hours @ $110/hr = $31,460 Garmin doesn't supply a lot of common materials needed for installation, so there was a itemized materials charge of $2,497 The avionics was $47,817 The G3X included 4 cyl EIS. GFC 500 did NOT include yaw damper. I also had CiES fuel transmitters installed. The labor was a little reduced because I supplied the airplane with the interior panels removed and I reinstalled them. Skip

The other problem with the darn things is that they are open to the weather. According to PreciseFlight when I called them, the motor and microswitches often get water in them and fail.

EXACTLY. When you load the approach and make it active, the navigator provides VLOC course guidance to the CDI, but the GPS drives the map and still sequences legs and reports distances to waypoints.

Is that for a pair and what series? I had a 100 series unit (one only) repaired for $1200 in 2021.

I installed a G3X, G5, PMA 450B, GTN 650Xi, GNC 255A, GFC 500, GTX 345 a year and a half ago for about 80K in an M20J.

You should save settings to the configuration module every time a change is made. If the configuration is up to date there is no problem losing data. But, it never hurts to save again before doing anything. Also, I keep a backup hard copy of the configurations I got from the installer just in case.

Although the manual does say the SD card must be in the unit, once it downloads an update to internal memory it does run fine with the card removed. The only reason I can think that it needs the card is for backup if the internal memory has a problem, but who knows -- Garmin doesn't explain this.

Should be there if it was properly set up in configuration mode

$150 labor sounds like an hour at shop rate which is probably the minimum charge and not unreasonable. But since it is easily field replaceable, I would probably buy a battery, remove the cover and replace the battery myself since it doesn’t require more skill or knowledge than operating a screwdriver.

Also, an incandescent bulb will get very dim but generally LEDs cannot get as dim without flicker, so they limit the dimming range. But LEDs dim without changing the color temperature.

Look on the schematic (vol 2 of the service and maintenance manual) for the component designation. Then look in the electrical section in the back of vol 1 and find the manufacturer and part number. The manuals are available from Mooney on pdf if you can’t locate one in the downloads section or elsewhere.

The places where the trim system usually binds are: The jackscrew in the tail hasn't been lubricated recently, the trim servo is binding, the chain from the trim wheel to the front gearbox is too tight. Also, with a trim servo installed it is good to ensure that the trim system stop nuts are the newer stepped type to prevent the trim servo from jamming the trim system at either extreme. The trim being "tight" is kind of a relative determination. Because you are turning a jackscrew and moving the entire empennage, rather than a tab on the elevator the Mooney trim wheel is harder to turn than say a C-172. But it shouldn't require undue force. I make it a habit to always return the trim to the takeoff position after landing manually so that I can tell that the trim feels normal. And, occasionally I run it from stop to stop manually just to check. Skip

My comment was based on the above description of the accident. There are times when it might be better to damage the airplane to improve survivability. Given the fire damage, I hate to think what would have happened if the door had jammed.

Well, perhaps this counters the idea of leaving the gear down on takeoff until there is no more runway available. The plane will stop faster on the remaining runway with the gear up. Not faulting the pilot; just something to think about.

Apparently the internal battery is used to keep some memory alive to store the GPS constellation almanac.

You will need to completely remove the fitting and clean the threads. Since it is steel, it is unlikely to be damaged. Coat it with sealant leaving the bottom two threads clean (I suggest Armite LP-250) and reinstall it.