PT20J

Today was a good day for a test flight in my M20J with very smooth air. The GFC 500 performed much better than I remembered from previous tests during an IAS climb. I did it twice with similar results, recording the second one. The test sequence was as follows (the AP was engaged for the entire sequence) : Start in level flight, ALT mode, 1500 MSL, 142 KIAS Switch vertical mode to IAS Set altitude bug to 3500' Set IAS bug to ~96 KIAS As the climb begins, increase power to WOT (prop was already at max RPM) The autopilot initially had some pitch variation but not more than 2-3 degrees and increasing power seemed to aggravate that. But it settled down pretty quickly and did a nice level off at 3500'. https://www.dropbox.com/s/s3lzac6l0xj6zr4/IMG_4718.MOV?dl=0 Skip

That would only apply to models that had squat switches. Did any M20Ks have squat switches?

It that’s it it will trip the Gear breaker, so if you reseat the lever, check the breakers, too.

May bethe airspeed safety switch. Does the red button next to the gear switch light up and if you press and hold it does the gear then retract?

Naw, I’m just saying that I decided it was as good as the GFC 500 IAS mode worked and I had figured out how to live with it. Garmin seems to come out with software bug fixes for its equipment at a rate that surpasses Microsoft, so I figured that maybe someday it would get better.

Perfect timing - I only flew a GFC 700 once in a C-182 and it was 10 years ago and I don’t even remember if I used FLC (aka IAS), so I was wondering if it worked better in that autopilot. Probably works well in the GFC 600 then also. Be interesting to ask the Beech guys.

I would first measure the voltage at pin 23.

On mine, if I take off and climb out and then engage the AP in IAS mode it does a reasonable job of holding airspeed with minor pitch excursions. In turbulence, it can pitch a little excessively like a student pilot chasing airspeed. If in level flight I engage IAS and dial in a lower speed to initiate a climb, I have to dial down the speed slowly in 5 kt increments. If I go too fast, the autopilot chases the phugoid and pitches up and down excessively. But, it always damps out after about 2 oscillations which is the natural response of the airplane. All other vertical modes are rock solid. Skip

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Oh, man. You've really been through it with this. When I saw your post, I was sure you were going to tell me it was fixed. Keep after Trek until they figure it out.

Did you do the magnetometer calibration on a compass rose after installation?

Seems to me that the best approach to preventive maintenance is to just replace the entire airplane with another before anything fails. You don't even need a logbook entry.

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It doesn't get all that cold where I live. But I often fly at altitudes where the OAT is freezing or below. In my M20J, I only crack the heat knob, or more commonly open it a little farther and mix with cold air to get more control. If I open it more, it gets uncomfortably warm. This is in cruise with the cowl flaps closed -- the head output is noticeably less with the cowl flaps open, My airplane had the foam insulation on the sidewalls from the factory. When I had the interior out, I removed all the old fiberglass that they still used on the ceiling and baggage compartment and replaced it with the same foam which I bought from a MSC. I think that made a difference. My hangar isn't insulated and in the winter and it is often in the thirties (F). When I want to do some work in the cockpit, I throw a little ceramic heater in the baggage compartment on a low setting and it keeps it very comfortable inside. Skip

I don't know if they are the most robust or not, but Garmin equipment is generally well made. I like the way that the G3X, G5, GTN 650Xi, GFC 500 and GTX 345 integrate. It's as close to an affordable integrated flight deck as I could get with Garmin equipment that is not certified by the airframe manufacturer (like a G1000Nxi or a Cirrus Perspective)

Not in my experience. However, I would update to the latest software. Garmin has made some changes that they claim improve the AHRS performance including a bench calibration that might help. I haven't tested it because the G3X installation disables the GTX internal AHRS. The GTX Bluetooth still transmits AHRS information, but the source is the GSU 25D or the G5; not the internal AHRS. Skip

My airplane had them installed at the factory. I believe it’s a Mooney part, not a standard part. The original design was just jam nuts that could, well, jam. The step nut design engages the step to stop rotation without adding friction to the trim system.

I don't think it's LOP vs ROP -- I suspect it's power. Run them hard and they don't last as long. Mike Busch runs pretty low power. I asked him once what power he ran and he said he had no idea but it was probably 60-65%. He just has a fuel flow that he likes to run at and watches the head temps and adjusts mixture accordingly. He summed it up with, "I'm a longevity guy, not a speed guy." The airlines used to run the big radials at around 55% rated power for economy and longevity.

Autopilot kind of refers to the entire system. The KFC 150 has a flight computer KC 192 that is the brains. It is the panel mount unit that has the pushbuttons and display. Look back up this thread to the diagram I posted that shows all the components and how they interconnect. The FD is part of the autopilot. The autopilot computer gets navigation information from the navigator, course and heading information from the HSI and attitude information from the attitude gyro, and then it computes a pitch and roll solution which is displayed on the FD. If you engage the autopilot, it also drives the servos to fly the airplane.

SIM20-88A and SBM20-325

The autopilot has a computer that drives both the command bars and the servos. It's the same thing. The command bards are just a visual indication of the computer output. If you manually follow the command bars you are just doing what the servos would be doing if you switched from FD to AP.

By that logic, you could replace the engine as PM I would like to see him explain that to the FAA though. That would be fun to watch.

Well, Appendix A says you are allowed troubleshoot and repair broken landing light circuits so it's not much of a stretch to say that the repairing charging circuit wiring is allowed by similarity. And Part 1 says that preventive maintenance includes replacement of small standard parts not involving complex assembly operations. So with a bit of a stretch you could probably argue that an off-the-shelf direct replacement voltage regulator fastened to the airframe with four screws is a small standard part. The Coleal legal interpretation makes it unclear. Me, I'd have my A&P look it over and sign it off.

Many years ago, I taxied out of a tiedown with a chain still attached. Pop. Pulls the ring right out. I took it to my mechanic and he laughed at me and handed me a helicoil kit. I was able to use the original tiedown eye afterwards.

I believe it should work as you describe, but I would definitely test it.