EricJ

That's the miracle of the modern serial bus; very few wires and everything gets interconnected. Pre-manufactured harnesses have been a thing for autopilots for a long time. The harness for the Century III that was installed in my airplane at the factory has a bunch of big loops where it was way bigger than it needed to be so they just coiled it up. I suspect it was designed for a King Air or something. The BK Aerocruz comes with a harness, or at least it's an option to order. It's not unusual since the wiring diagram is pretty consistent from airplane to airplane.

In motor racing the usual wisdom was to have both the inlet and outlet at the top, which makes an awful lot of things easier and assures that the cooler is more likely to be purged of air. The next best way is to put the inlet at the bottom and outflow at the top. Radiators usually go the other way because there's an independent purge and fill system and you want to maximize the likelihood that there's coolant at the bottom for the pump to draw. For whatever reason a lot of oil coolers get set up differently, though.

Forty years of thermal and pressure cycling might be enough. The diaphragm, spring, and microswitch probably change characteristics over that much time and cycles. Even if it's not leaking, the diaphragm might be stiffer or something. I'm just speculating, but with old stuff you never know.

That was some good planning there. I like how you did that.

If you use 2024-T3 aluminum of the same thickness you can't go wrong. You can buy that at aircraft spruce or many other places. A drill strap, or strap duplicator, lines up holes with the piece in-place so that you can drill the hole to match the work. They're very easy to use. Hold the piece where you want it and use the strap to drill the first hole, put a screw in that hole with enough slop so that the strap can line up the next hole, etc. Like this:

That's pretty easy to make. A sheet metal shop or ambitious individual can fab one. Take the other side as a pattern, leave it undrilled, and borrow a drill strap from an A&P or home builder to drill the holes.

The latest rev for the Mooney TCDS 2A3 is 58, which is the one I was referencing. The airframe TCDS supercedes the engine TCDS, so it drives in determining what can go in the tank, placards, etc. And the Lycoming SI1070 is a very good reference as well. There are definitely more than one standard when it comes to most things.

The TCDS for most of the earlier Mooneys says, "100LL or 100/130 octane minimum grade aviation gasoline". For some of the later ones it says, "Fuel 100 LL or 100 min-grade aviation gasoline". Anything that meets those won't need an STC and would be genuinely drop-in. There's no definition or standard specified in the TCDS, so I've always figured whatever it says on the dispensing tank would be a reasonable field interpretation as far as "minumum grade" goes.

I don't know of anything that would keep you from doing that. I kept my Century III after my avionics upgrade.

The other side of that is to recall that the J model was essentially a big exercise in doing drag reduction on an F model, and they left the fixed step. They just made it an option to delete it. I don't think I've ever seen any numbers published on what difference it makes, and I bet if they thought it made a significant difference it would be in the marketing material.

My J has a fixed step. At least in the early J's the step was an option. One of the local early J models had no step from the factory and I thought it made it pretty uncomfortable to get on and off the wing.

The standard is ASTM D910. I have a copy of -11 which is from 2011, but they're up to -21 now. It's unusual for a standard to specify how to do something, just what characteristics the item must have. In this case the Octane numbers and anti-knock values are specified, and maximum levels of TEL (so that it doesn't exceed environmental and other requirements) are specified. If a fuel can meet all of the other requirements with less or no lead (TEL), it isn't required. The only TEL requirement is that it not exceed specified amounts.

It varies among the autopilots. The Garmin GFC500 is an expensive installation, but a very good autopilot. There are a couple other pending options that are easier (and cheaper) installations. Garmin made the installation complicated for some reason, but it works.

I've never had one apart, but they're not complicated. Parts and replacements are not easy to find, but it might not be too tough to repair if it needs more than adjustment.

Can be done, but not accessible for many.

A leak in the switch diaphragm would also show up in a pitot leak check, which is pretty easy to do. I wouldn't be surprised if it just needs adjustment.

Installations of various autopilots vary significantly, so there isn't a lot of re-use of installation infrastructure when installing a new one. So the main difference in installing any of the autopilots in your airplane is that in your case nothing needs to be ripped out, so that'll save some effort.

I'd think the ASI would be off as much as the switch if it was a pitot pressure problem, unless there's something in the line between the two.

At the event I attended at the Buckeye Air Fair, George essentialy said that G100UL is a stronger solvent than 100LL, to not let it get on your paint for very long, etc., etc. I suspect that one of the (potentially many) reasons that the manufacturers (and others) are hesistant to take a position is that the long-term effect on sealants, seals, gaskets, and other materials is unknown. It's been discussed here before that one of the things this affects is the distributor's ability to insure liability in the distribution and vending stream. Our local fuel vendor brought this up at a meeting as one of the current barriers to adoption of G100UL. So the tank leak might be a result of that.

There are at least four vids, two of each case. There's also a vid or two of the guy that flew into the tower. This latest case I didn't think was so bad, as the guy was communicating what was going on, and was taking instruction and assistance from ATC.

These days you could duplicate that with a $35 RTL-SDR USB tuner and a Raspberry Pi. I'm surprised nobody has done it yet. I was thinking of doing it but I have other projects in the pipeline. It'd be a nice backup for if/when GPS goes down and just operate off of the MON VORs. Could even integrate it in with the Stratux so when it detects GPS loss, it gives a lat/lon estimate from triangulating off the VORs as a substitute for the GPS output.

Apparently it's been around a long time but this is the first I've heard of it. There must be some barrier, maybe cost, that has kept it from becoming popular.

The bypass is mostly just so that you can cycle the gear on the ground during a routine gear swing or other maintenance, but does also let you bypass a faulty airspeed switch. It sounds like maybe the airspeed switch is just a little slow or sticky or something.

To me the main advantage of airplanes like an A36 or Saratoga is the ability to easily throw a lot of crap, like bicycles or something, in them.

Or just get an Android.