PT20J

If the trim system is part of the autopilot, the yoke mounted autopilot disconnect will disable the trim servo. So, for any uncommanded pitch, even with the autopilot off, the first action would be to press and hold the disconnect button. On airplanes with manual electric trim and no autopilot, runaway trim will require turning off a switch or pulling a circuit breaker.

Here's the interesting question: what will you do with it? You can't wait until the installed one breaks because then it is too late as they seem to jam the gear when they break. You could replace it at 1000 hrs as recommended. But then there is the maintenance-induced failure risk, and how do you really know that the new spring is better than the perfectly functioning one you replaced? There is the fact that according to Don Maxwell they do wear and begin to chatter, so I guess if that happens you have a spare. But he also told me that he was told that the gear actuator is rated for 20,000 operations. So, they should last a really long time. Maybe it's like insurance and the primary value is a good night's sleep .

Based on the choices presented, and the title and description, we will assume that it is a coupled approach and that the airplane is suddenly pitching down and rolling. We will further assume that the airplane is not physically broken (in which case you are dead) and that the errant behavior is due to an autopilot malfunction. Keep manually overriding and continue to land: Bad choice since the autopilot will trim against your input and you will end up with full down trim which in my M20J I measured as requiring a 50 lb pull to maintain level flight. Turn off the auto pilot: Best choice. Push and hold the disconnect switch on the yoke while regaining control and manually trimming and then pull the AP CB. Shut the master switch: Overkill and you will lose navigation and communication and any electronic instruments. Shut off electric trim: Depends on the autopilot. On some, the trim CB only affects manual electric trim and not the autopilot's ability to control the trim servo. Also, it will only affect the pitch axis and since the airplane is rolling something else is going on with the autopilot. Find and turn off a circuit breaker: As stated above, this is the terminal action to kill the autopilot after control is regained. But it is not the best choice for a first action since it will distract attention from controlling the airplane. Note that on a GFC 500 with ESP enabled, if you get slow on approach above 200' AGL with the autopilot disengaged, the pitch servo will engage and push the nose down. Unlike the deadly Boeing MCAS, it will not run the trim servo, however.

PIT is the default setting if no other vertical modes are selected. When the AP is first engaged it will hold the current pitch attitude unless you select another vertical mode. You can use the thumbwheel to adjust the attitude. If another vertical mode is selected, cancelling it will revert the AP to PIT.

That makes sense. The last thing Mooney needs right now is more unsecured creditors I know of at least one MSC that offered to front the money for Mooney to order the no-back springs, but the offer was declined. The licensing deal makes sense for everyone (well, except perhaps for the cost).

My M20J has a pi filter and a 3000 uF capacitor located behind the circuit breaker panel to filter the alternator output. The capacitor is cheap to replace and electrolytic caps can degrade with age.

I have the original gain settings. It holds airspeed well in smooth air. It chases it a little in turbulence, but I have a hard time holding a constant airspeed in turbulence manually. I use PIT if it’s bumpy. Tightening the pitch servo bridal cables to max spec helped.

True. The important point is that you need Garmin equipment to support the GFC 500 and sometimes people forget that when pricing the autopilot. I still believe the best setup is a G3X/G5/GFC 500 because this combination is one of the few Garmin configurations besides the G1000 that was actually designed as a system. It gives maximum redundancy, and the G5 is a great backup for an airplane without a vacuum system because it has a long backup battery run time. This is not to say that the TXi is not a great product because it is. And if I already had one, I would not replace it with a G3X when adding the autopilot. But, when starting from scratch, I weighed all the pros and cons and went with the G3X/G5/GFC 500. Lower cost, redundant ADAHRS, longer backuo battery life, older hardware.

Great autopilot. Just be aware that you need a G3X, or dual G5s, or dual GI 275s to run it as it’s not a stand alone device like legacy designs. The software is in the Garmin PFDs.

Probably helps to have full tanks and some friends in the cabin.

If it’s engine related, the rate of ticking should vary with rpm. Strobe lights can also make a tick. If you think it’s spark, check the resistance (5000 ohms max) of the plugs before replacing stuff. High resistance stresses the wires.

I agree. After Mooney gets it's licensing fee and LASAR gets it's markup, the prices will be high (and CBs will complain) but at least we should be able to get some parts and Mooney can focus its limited resources on manufacturing the parts that it makes.

Well @LANCECASPER says Mooney is keeping a back order list. @Pinecone says no. So, now I'm confused.

Both are correct: different models with different elevator control systems as explained in the thread above. The autopilot doesn’t have anything to do with it.

OK: 100 x 5 x $35 = $17,500. Still not pocket change. Assuming Mooney sells 10 of each part number per year, that's a ten year supply. Do the ROI math on that at whatever interest rate you assume and make it pencil out. Personally, I'd rather Mooney spend the money on parts that keep the airplane airworthy. Sure, I'd miss one of my wing gauges if it disappeared and I couldn't replace it. But, I could still fly the airplane. I can think of lots of parts that could ground the airplane if I couldn't get one from Mooney. I was happy that Mooney had just made a batch of nose gear legs when an FBO damaged mine. @LANCECASPER described how to get Mooney to make parts. So, if all of us that had wing gauges ordered two, it would only take 50 orders of each part number (assuming that the min order is 100) to get them made. Who knows what the price will be, but it will certainly be only a few hundred bucks which is a round off error in aviation costs. I'm going to order two on Monday. Anyone else with me? Or is everyone just going to complain?

Here's the problem: If the minimum order is (reasonable guess) 100 per part number, and there are 5 part numbers, and perhaps the cost (to Mooney) is $75 each (guess) then that's 5 x 100 x $75 = $37,500. Now, there is only an occasional post here looking for one gone missing across all these part numbers. Most Mooneys don't even use them. So how many of each part number would Mooney sell per year? Probably less than 10; maybe way less. Now perhaps Mooney could get enough orders to make it make sense if everyone that had them ordered one or two as spares, but then many owners are self-proclaimed CBs and feel ripped of paying $140 for a "$10 part" (perceived value) and would not want to do so unless theirs actually went missing. I've talked to the owners of a couple of well-known, long-term MSCs. They generally don't enjoy selling parts, though of course they will do it since it is part of being a MSC. The reason is that many owners order the wrong part, complain about the price, then find out it's the wrong part and want to return it. If it came from the factory, Mooney charges a restocking fee (20% if I recall correctly) which they complain about. There is not enough markup in the parts to make it worth the hassle. That's why most MSCs were happy to let LASAR (which is just another MSC) have most of the parts business.

Curious how the old one was damaged. I wonder if some tried to assemble it with out the circlip and it got cocked in the cup?

If the screen isn’t torn, perhaps you could just straighten it. Otherwise the one on eBay might be serviceable.

My 94 M20J has the 610015-001 gascolator. It's an Airight 51250-9 with a red can. The screen isn't flat; its a cylinder. See drawing attached. There's one listed on eBay for $69 obo described as for parts only. You could contact the seller and see if the screen is good if this is the one you need. https://www.ebay.com/itm/365014530937?_skw=airight+gascolator&itmmeta=01JPBHD6K87BFDGJ82M6691XPS&hash=item54fc8fbb79:g:NOgAAOSwofxmlrbp&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1e8giZ%2Fo0Fmdx519imTQZxM8mY%2BgxLKR4ABUUt1Q3BIa%2BmiPO4GTjs0O0HZVBFkX0Gw9T2o52%2BT7ksDVvXiXZxgmDg7Z%2BI%2FnDSHaSF3ye%2BJ8%2FEcyh%2BXpQuEjS%2F7iRflZDqjiWzPlj0JfA8a0uy9jrZf2DvynXltw%2F%2BmD0aiVBPHHks5atZn0mY06bf8gDKJWbd%2BNztIlGelGnFECshWndxIHxCkB97w9RdXntgjnMuM91iQre2ewyohIndRG5bhMQ2ZvOqzoeSOe14H1NR620A70EV9MBTExC%2Fsx%2BsX5%2BW2jA%3D%3D|tkp%3ABk9SR8DqtPGyZQ Airight 51250-9 Gascolator.pdf

That's the stuff I used. It's supposed to be water and UV resistant. So far it has held up well.

I would expect a bad switch to cause the servo to stop suddenly. Slowing to a stop seems more like a mechanical issue. If it trims easily manually, it might be a slipping clutch in the servo. @Jake@BevanAviation might have some ideas.

What autopilot do you have? Electric trim is part of the autopilot if an autopilot is installed. Usually trim problems are due to friction in the mechanical trim system. Does the trim move easily when you manually rotate the trim wheel from stop to stop? Is the problem only on the ground? It is harder to trim up than down on the ground because the trim jack screw in the tail has to raise the empennage against gravity. The Bendix-King servo is pretty robust. The Garmin servo is barely adequate because the gearing necessary to make it move fast enough reduces the torque.

The import button is probably greyed out because the G3X doesn’t recognize the csv file. According to the G3X pilot’s guide, the import file needs to be a GPX file. EDIT: If Garmin Pilot will not export in GPX format, I believe there are online csv to gpx converters.

On my 1994 M20J I'm paying: Liability $1,000,000 smooth - $684 Hull value - $250,000 Hull premium - $3806 (hull rate 1.522%) Total - $4490 ATP, 5700TT, 1768 retract, 1328 make/model

When you replace the suction screen, be sure to use a new crush gasket, split side toward the engine and tighten 135 deg. If it were mine, I’d borescope the cylinders. When mine made metal, a oil control ring broke and scored a cylinder.