PT20J

I believe Honeywell makes alternate action lighted square pushbuttons. Should be lots of sources for the machined crimp contacts. Aircraft Spruce lists them. EDIT: Steinair has the pins and a crimper less costly than the DMC. https://www.steinair.com/product/contact-high-density-dsub-pin/

I have two sets (one landing and one taxi light per set) of bulbs installed in 2018 and removed in 2022 when I upgraded to the G3s. I's asking $149 each which is half the price of G3s https://flywat.com/products/parmetheus-plus-par-36-led-landing-taxi-light

Try https://support.garmin.com/en-US/?partNumber=K10-00280-01&tab=manuals

The best thing is to make sure that the muffler is sound -- that's the main source of it getting into the cabin. In flight, the airstream should carry the exhaust away from the cabin.

Sometime in the mid-1980s Mooney switched to foam insulation, epoxy primed tubes and sealing the rivets that attach the window frames to the tubes. On those airframes, it it often a simple matter of checking that the pilot's storm window doesn't leak and removing the belly panels and checking for corrosion in the bottom tubes. A complete by-the-book inspection removing the belly, side panels, rear seat and tension bolts and putting everything back together is probably $1000 at a shop. @jetdriven would know. I might contact Frank Crawford at Mooney with the model and serial number and he should be able to look up the build records and tell if it has the updated insulation and primer. I bought bulk foam insulation that Mooney uses from a MSC for $475 and installed it myself. It took me maybe 4 hours to remove the old insulation and cut and install the new.

Last summer I noted a faint fuel odor in the cabin when the airplane had been sitting for a day or so closed up in the hangar. I traced it to a tiny seep from a screw attaching the right outboard fuel sender. The vapor travelled all the way down the leading edge of the wing to the cabin. So, it doesn't take much to be detectable by smell. A big leak will definitely be noticeable. And, BTW, if you think all that duct tape covering the gap at the wing root will keep CO out -- it won't.

It must be a lot harder on the K than the J. I bought new seals from Guy @Gee Bee Aeroproducts when we swapped out the engine. The hardest part was removing the hardened staples attaching the old seals to the baffles which I did with a Dremel cutoff wheel. It probably took me an hour or less. My A&P attached the new ones with the pop rivets that Guy supplied in less than an hour.

This^^^^

I don't know who made the one that Mooney used, but Lone Star Aviation makes one and the website has a Bode plot https://lonestaraviation.com/wp-content/uploads/2017/09/70-Amp_freq_graph.pdf?v=47e5dceea252 Looks like the cutoff frequency (-3 dB) is about 13kHz and maximum attenuation is about 70 dB at 220 kHz. The load resistance for the test is unclear -- probably 50 ohms to match the signal generator impedance.

Excellent question. From the M20J Service Manual:

Hard to test unless you know the specs. It’s a pi low pass filter which is third order so it should roll off at 18 dB/octave but you’d have to guess the cutoff frequency unless you can get a spec sheet. I guess you could put a signal generator on the input and an oscilloscope on the output and plot the frequency response to see if it looks reasonable. Crown probably has the test equipment from when Larry was there and did bench repairs. Its purpose is to filter out rectified DC noise from the alternator. The best test is whether you heard alternator whine in your radios before the upgrade. If not, it’s working.

Actually, that's a recycled Citation joke from 35 years ago when the early Citations were derisively called Slotations. Still, Cessna sold a lot of them. Crow all you want about how much faster/more efficient a Mooney is than a Cirrus but Mooney is not producing airplanes (and most likely never will again) and a lot of parts have become unobtanium while Cirrus is selling lots of airplanes. Apparently the people that can afford a Cirrus are indifferent to fuel costs.

Heading for SJC for the 30L ILS one night many years ago and the controller was trying to get us lined up behind a Citation. My copilot and I noted that this would be interesting because I was going downhill -- fast single, slow jet. Sure enough we ended up closing on GILRO at about the same time and distance. I offered to slow down and let the Citation go ahead -- that airplane is a lot more expensive to operate than mine and I wasn't in a hurry.

+1 for the dual lock. I used it to attach the rear seat side trim panels and it holds well even in the summer heat.

“Then turn right 30 degrees, vector for spacing.”

So when we are faster, we brag about speed, and when we are slower we brag about economy. Can’t beat a Mooney pilot’s logic.

Looks a lot cruder than my factory belly on my M20J. Also, the holes for the cross supports don't seem to be in the same place as mine. And, what are all those large circles and little bumps on the inside?

I know of one M20C that has a one off STC for a fiberglass belly panel that the owner made.

Back in the '50s and '60s the manuals were pretty skimpy on procedures. The manufactures assumed that pilots possessed some level of airmanship and knew what to do if the engine quit. The POH standard didn't come out until the General Aviation Manufacturers Association invented the format in the mid-70s. Airplanes produced after that had more info. Nowadays, the failures I'm most worried about are not related to the engine or landing gear or other simple systems -it's the complex glass panel avionics that are interconnected in mysterious ways. Quick: Your G3X annunciates ATT MISCOMPARE. What do you do? I keep thinking I need to create a QRH for my avionics suite.

Maybe there is a hidden message here: Don't over label things or it will get expensive. Here's a CB option -- get 12 MSers to do group buy and they are only $.83 each

$2.85 is expensive? Really? I spend that for a latte. Anyway, if you look you'll find that Spruce sells them cheaper than most other suppliers. But if you are really a CB just "borrow" your wife's fingernail polish. I only banded the autopilot and speed brakes. I pull the speed brakes any time I turn on the pitot heat after brushing the yoke switch once while picking up some ice and the left one wouldn't go back down all the way.

The original airplane was built by North American Aviation and designated AT-6 (except the Navy called it an SNJ-3 and the Canadians and Brits called it a Harvard). AT was the designation for Advanced Trainer. After WW II, they were sold quickly for cheap as surplus. But then the newly-formed US Air Force discovered that it needed a trainer and it bought back several hundred (at much higher prices) and awarded North American a contract to update them. These were designated T-6Gs. I have a friend that owns a really nice T-6G and I have about 5 hours in the front seat. I've got another 5 or so hours in the back seat of an AT-6A mostly flown with an ex-Reno race pilot. If you think a Mooney stall is wicked - try a T-6 .

You don't want to aim for the numbers because if the wind changes (or you misjudge) and end up short, there is nothing you can do. But, if you aim at some point down the runway, you can slip or s-turn or deploy speed brakes if you have them or put the prop to hi rpm to increase drag.

Doesn't look like the factory belly on my M20J. Way too many holes along the perimeter and they don't look to be in line. Maybe the LASAR belly panel?

There are small variations and very large sudden variations. Clearly, the engine won’t run on zero fuel pressure, so there is likely a bad connection. I would fix that. The smaller variations might remain if they are caused by vapor as is common.