EricJ

The previous drawing, i.e., the one to the left of your thumb off the pic, shows the device installed without that jumper wire. Your installation doesn't have that, so the black wires are sufficient. Re-using that nice, white terminal cover might be nice, though.

Fires can be significantly accelerated with the addition of more oxygen. Fuse plugs blowing on a main gear tire would add a LOT more oxygen than ambient to a brake fire if they contained air rather than N2. An inert gas like N2 blowing on it will tend to help blow it out instead.

I tried to find it, but somewhere on faasafety.gov or somewhere else, Scott Fohrman of the FAA Chicago Air Certification branch has given several webinars on VARMA. He's one of the guys that helped create it, and I think the more recent presentations may be better, but I couldn't find an archive copy. If you are an EAA member they have a copy of the webinar from August of last year here: https://www.eaa.org/videos/vintage-aircraft If you get the webinar/seminar notices from faasafety.gov, keep an eye out for any potential upcoming events on the subject and you can get the latest. VARMA is Vintage Aircraft Replacement and Modification Article. It doesn't leverage any new regulations, all of the previous regs and ACs for vintage aircraft parts substitution apply, but the VARMA program established a process by which you could formally apply for a "VARMA letter" from the FAA which documents the approval of a part for the installation on an individual aircraft. That FAA document then serves as the "approval" for that part to be on the aircraft so that it can be shown to maintenance personnel and inspectors. It is not outside of any normal process, no new regulations or permissions are necessary, the only purpose of the letter is to provide a formal documentation that the part is compliant with existing regs and can be installed on the aircraft. A number of examples were given in the event that I attended, including installing a starter solenoid from NAPA on a C150, stuff like that. Note that a VARMA letter is not required to install any part, it only serves as formal documentation of approval of the installation if the owner desires it so that future IAs won't make them take it out. It was amusing to me to hear them describe this as an IA education program, and that if ultimately successful the program would put itself out of business once IAs stopped removing allowed parts.

Another unpopular opinion: The FAA rules aren't really that egregious, but how some people insist on interpreting them can definitely be egregious. Note that the VARMA program exists in order to provide owners documentation from the FAA that a part is okay to be on their aircraft so that the next IA won't make them take it out.

I think it's a lot easier for an independent mobile mechanic (which is mostly what we have around here) than an IA in a shop to provide owner assisted annuals. Having a customer banging around in a shop can definitely create issues, but if an IA goes to your hangar to do the inspection it's much easier to accomodate owner assistance. Another thing that makes it easier is if it is evident that the owner is reasonably handy with tools and is not going to do damage along the way. If you do some of your own maintenance, like oil and tire changes, etc., say so, as it'll convey that you may actually help things move along rather than be in the way. That said, some shops do allow owner assist, so it may be worth asking a shop that you'd like to work with. I suspect that sometimes when an IA says No to an assisted annual they're really saying no the individual rather than saying they don't do owner-assisted annuals.

The main reason the airlines use N2 is so that a brake fire doesn't get fed when the tire fuse plugs blow. I think that's one reason the military uses it as well.

I just flew a long cross country out and back in this experimental, which seems similar, and is very nice.

Might've been an ex-military controller or they just happened to notice. I popped the gear breaker on a go-around once years ago (it does that if you're too fast), and they let me know my gear stopped only partially up.

If you know exactly what you have, or at least the manufacturer, there is probably a product manual that you can download that will have cleaning instructions. For a Donaldson filter, for example, it's usually just to blow air through it.

Do you know what type of filter you have? If it is a paper filter just remove the filter and take some low-pressure compressed air (or high pressure sprayed from a longer distance) and blow out the dust forcing air from back to front. If you have access to compressed air, just use a common blower fitting and shoot it at the filter. I just do it from a bit of a distance to not damage the filter media. Depending on how dirty it is, sometimes you see the crud blow out of it. An easy inspection is to just hold the filter up to a bright light source, or even the sun, and you should be able to see light through the pleats. Do that before and after and you blow it clean and see if you tell any difference. If you have a bracket filter (oiled foam), don't blow it out, just order replacement media and replace it. If you have a K&N or a Challenger, there are manufacturer directions for cleaning (or just replace it with a paper filter). I'm not sure what all the filter options are for an M20R, but that's the general idea.

The jack screw is difficult to back drive and I believe the Mooney gear actuator is designed to not backdrive. This provides the actuation lock. I've not heard of one failing, while the manual downlocks have failed. And +1 that the overcenter mechanisms prevent gear collapse. This is why it's important to check their preloads.

Around Phoenix I'm usually turning the B-Kool off climbing out around 5-7000 feet even in the middle of the summer. That's usually sufficiently high to get up in the cool air. Once in a while it might be a bit higher, but not much.

Yeah, gonna be hard to do on a tube if it's been inflated before and in the assembly already. The main culprit for causing excessive pressure changes due to temperature is moisture. N2 is generally dry, but if the air you put in the tire is dry, too, then there's not much difference. There was a period of time when some of the guys I raced with tried N2, but in AZ the air is dry enough, anyway, and it's not hard to put a drier on your compressor to take out any remaining moisture if you care. After a bit of experimenting I didn't know anybody in the paddock that still ran N2. Everybody just went back to air. A bunch of people ran wheels with the dual valve stems, but just used air.

In AZ we just deal with it. I generally fly in the mornings and take the B-Kool along. I did a four-hour trip a week and a half ago which included stopping in Seligman for lunch, and then returning to DVT (Phoenix) afterward, and the B-Kool was still frozen enough to keep the cabin cool for landing and taxi to the pump and then the hangar. It's a lot less fun without that. Many of the flight schools around here have AC in their airplanes, even the Archers, but some don't. They still fly, they just suck it up. Kinda brutal, but they do it.

I'm familiar with that airplane and have talked to the owner before, once at the fuel pump when we happened to be there at the same time and then once or twice on other occasions. I've heard both that there was a bird strike in a flock of birds, and that there was fuel starvation. We'll probably have to wait for more reliable data or an official report.

Dual mag, the impulse coupling drives both sides.

We may not have done 60, but we did a lot. The bend planning and other details were the sorts of things where it became obvious that if you didn't do it regularly you weren't going to be proficient at it.

Was just gonna +1 to try it with the p-leads disconnected. It needs to have the timing plugs in place to assure that both sides are hot. That should help isolate whether it is a mag or a switch issue. It may also be worth checking to make sure the switch is configured properly so that both sides are hot during start. That's one of the advantages of the dual mag.

Yes, and that's partly why turning the master off is always a potential thing to do if there's smoke in the cockpit, especially if it smells electrical. Then turn everything off and turn things back on one at a time. If you can't even turn the master back on without issues, then that's probably the sort of fault you just found.

The easy way to sort out whether it's battery or alternator power that trips the breaker is to just turn the master on without the engine running. If it trips the breaker, the current is coming from the battery and there is likely a short between the breaker and the alternator, or in the alternator (which has been changed and didn't fix the problem). If the breaker doesn't trip until the alternator is running, then the issue is likely between the breaker and the other distribution buses or the circuit back to the battery. Since the battery would supply current to a fault on either side of the breaker once the master is on, if that doesn't reveal something getting hot somewhere then the issue may be the breaker itself.

It depends on the tug. Many tugs that capture the nosewheel still turn the nosewheel when the tug turns. A few, which seem to be rare in my observation, have a turntable that allows the nosewheel to be free when the tug turns. Just my observations.

You can also measure the OCV of each battery independently. If there is a bad cell in one, it may show up that way. A dead or weak cell is just one thing that could be wonky, it may not be likely, but it should be fairly easy to do some basic checks (like overall OCV, OCV of each, etc.), and recheck the charge current characteristic and get some basic ideas about the battery health.

Wherever the fingers point.

I mentioned that Mooneys have tight steering limits to one guy that was hooking up to move my airplane out of a hangar and he said, "They all do."

As mentioned previously, if the tube got pinched somewhere in the previous installation it could have just finally failed. Or, if it was too seriously underinflated it might have stressed the valve neck and caused a leak there. Sometimes a pinch or a fold is easy to see in the old tube after it's removed. It'd probably be worth putting some air in the old tube and see where it leaked to try to sort out why it did that.