PT20J

The RSA troubleshooting manual suggests that it might be an air leak in the fuel line somewhere. 15-810_B.pdf

Does the engine run smoothly? I would think that much variation in fuel flow would create some roughness.

I created a slurry with MEK and white LEGOs, but I've also just used black ABS pipe cement from the hardware store. I put down a thin coat of cement, then press in a piece of glass cloth, then add some more cement, then more cloth and finally more cement. Usually two layers is enough unless it is an area of high stress. You don't want a big puddle of glue -- just enough to saturate the cloth. Acid brushes work well for applying the cement. I had to do some extensive repairs on my glare shield and that is the only part I had to sand down and texture. I used a SEM product called Texture Coating. You can get a variety of textures. I just sprayed it lightly which provided a light sandpaper-like texture. You can spray it on heavily and even use a putty knife to knock it down to provide other textures.

Control surface static (mass) balance can be designed in for reasons other than flutter. Balance affects control forces and stability. When done for flutter reasons, the idea is to move the surface CG at (balanced) or ahead (overbalance) of the hinge line. This causes the inertial reaction to a gust (or other pressure disturbance) to create a moment that opposes rather than reinforces the motion. The susceptibility of a control surface to flutter depends on a number of things in addition to mass balance such as structural rigidity, control surface size and shape (large surfaces and especially surfaces with wide chord are more subject to flutter than small, narrow surfaces), and control system rigidity and friction. If balance (or overbalance) is not needed for flutter prevention, then balancing can be used for stability and control force tailoring. A underbalanced elevator will increase responsiveness to initial pitch changes. However, with a constant pitch rate (as in a level 2g turn, for instance) it acts as a bobweight and will increase stick force.

That's what I do. I use two or three layers of cloth. It also works well for reinforcing around screw holes where cracks start to form.

I did a quick look at Part 25 and it specifies a max vertical speed at touchdown of 10 fps (600 fpm) at max landing weight.

Everybody's got their favorite technique. I usually approach with takeoff flaps if it's gusty. This allows a higher deck angle for less flare, less drag and a higher approach speed. I add 5 knots above what I would use with full flaps at my weight and if it's gusty and the airspeed is bouncing around I adjust so that the lowest airspeed hits my planned approach speed. I fly a crabbed approach until about 50 feet where I adjust to a wing low attitude to test if I have enough rudder to straighten out. There is a limit to how low you drop a wing since the tips are not very far above the ground.

Actually, I've been thinking that Boron Nitride lubricants might be the best. BN is really slippery and it dries without leaving any oily film. Dupont has a number of lubricants using it and there are other brands as well. DuPont_Lubricants_Catalog_2022.pdf

The latest addendum didn’t change the primary settings. It did provide some optional settings to be used if “pitch or pitch trim is overreactive.” So, most likely an installer would start with the standard settings and only use the optional settings if unable to resolve pitch issues otherwise. My understanding is that while the autopilot is primarily attitude based, it does have a rate component to improve dynamic response and apparently this causes problems in some airframes. The changes dial back, or perhaps eliminate, the rate component.

Any tire is legal so long as it meets the size and ply specs in the TCDS. For Goodyear tires: Flight Custom III has deeper tread and a Kevlar belt and will last longer. Flight Special II is cheaper. Usual recommendation is for Flight Special II unless you do a lot of landings. Then FC III is probably the better buy. https://www.goodyearaviation.com/resources/pdf/Aviation-Databook-2022.pdf

A while back (I believe it was update 20.30) Garmin made the option available to delete the self test screen. The self test is designed for analog equipment to make sure that the attached navigation instruments are functioning properly. (This is the screen that shows half deflection of needles and 135 deg RMI, etc). The self test isn't necessary if the GTN Xi is interfaced to Garmin PFDs because the interface is all serial/digital and it either works or doesn't and if it's not working the PFD will display an error. If you have a Garmin panel and wish to delete the self test, you can do so in configuration mode. The GTN Xi maintenance manual (available on Garmin's website) Appendix A contains a form that lists all the configuration options. If you don't have a current one, it's not a bad idea to go into configuration mode (described in the manual) and record all the current settings. That way, you have a record of how it's set up just in case the configuration gets messed up during maintenance. Dealers are supposed to verify all the settings before and after a software update. But, stuff happens.

If you haven't already found it, there is a really useful feature that is kind of hidden and not well described in the Pilot's Guide. The Info Page normally shows the GPS Satellite Status, but there is a tab for a second page called Data Fields. This tab allows you to customize a large array of data fields to provide all sorts of useful information. The available field options are described in Appendix A of the Pilot's Guide.

I cannot imagine that the requirement that one set of contacts makes first makes a difference. According to the specification, the difference in plunger travel between the two sets of contacts making is only .010 +/-.005". If you are really concerned about it, you could call Frank Crawford.

According to the IPC, Mooney changed to the nylotron balls at M20J S/N 24-0901. Tri-Flow is what’s called for in the M20J Service Manual but later model service manuals say to keep them dry. Tri-Flow contains a light oil that doesn’t dry and will attract dirt that embeds itself in the plastic.

And ,the thing that causes the newer nylotron balls on the yoke shafts to bind is is lubricating them. The older manuals said to lubricate them but the newer manuals say to leave them dry. Lubing them attracts dust and gums them up. Keep the shafts clean and a little wax on the shaft doesn't hurt. Just don't spray lube into the balls.

One of the reasons that the 14V airplanes often have dim lights here is that Mooney used a 28V bulb apparently to avoid having it be too bright at night.

Lube the hinge bearings with a light oil such as LPS 2 and lube the rod ends with Tri-Flow. It's covered in section 5 of the service and maintenance manual.

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.