PT20J

Certainly true for older airplanes that didn't have the stepped stop nuts, but a M20V should be nonjamming.

The jackscrew is supposed to be lubricated and inspected at annual, but it often isn't. Some of the autopilots (the Bendix-Kings for sure) have trim servos with a lot of torque. If the trim gets stiff, and you always use the autopilot or manual electric trim, you won't notice a problem until it gets so bad that the servo clutch slips. I always reset the trim to the takeoff position by hand after landing using the trim wheel so that I can feel if the trim system is getting stiff.

It sounds like a trim runaway. In case it repeats, you might want to review the emergency procedures in the manual. Generally, the drill is to press and hold the autopilot/trim disconnect button on the yoke (which will remove power from the trim servo. Even if the servo is somehow mechanically jammed, you will be able to override the clutch manually), then trim manually, and finally pull the autopilot circuit breaker before releasing the button on the yoke. After the incident, does the GFC 700 pass preflight test? Skip

I would do whatever the service manual/IPC shows. If the hoses are old and not teflon, you might want to replace them and double check that the sizes agree with the IPC.

I agree with @EricJ. I’d check ALL the wiring connections and the alternator brushes before replacing anything. A quick search of the site will find lots of instances of people replacing regulators and alternators that did not fix the problem. Also, agree it’s not the battery. They will “work” until they won’t crank anymore because the alternator, not the battery, supplies power during flight. However, the capacity (amp-hours) decreases over time, and even though the battery may still “work”, if the alternator dies, you might only have battery power for a few minutes. This is an important consideration if you fly IFR, and it’s a good idea to get a capacity test annually.

Probably the best way to increase longevity is to run at lower power. Mike Bush told me he runs at about 65%. The airlines used to run the big radials less than 60%.

I think TBO is a statistical thing. If a large number of engines are run regularly, conservatively, with regular maintenance, some will make TBO and some will fall short, but the average should make or exceed TBO. The rub is that there is no way to know if a particular engine is average or not. As W. Edwards Deming used to like to say, “There is variation in everything.”

The FAA definitely has a position. The manufacturer can say anything they want but only the FAA determines the standards for airworthiness. That’s why everything in the POH is just interesting information EXCEPT the limitations section which must be approved by the FAA. If you exceed a limitation, you are in violation of FAR 91.9. Getting hung up on numbers is pointless. But there is a point. An engine that is 200 hr SMOH a year ago is not the same risk as an engine that is 200 hr SMOH 12 years ago (assuming the older engine was not stored in a preserved state).

Mine works, sort of. Since it doesn’t have a probe, it takes a bit time to come up with a calculated solution. So, if you fly a very stable approach in calm air, it seems reasonably accurate. But if your actual AOA is varying due to changing airspeed or turbulence, the lag makes it not very useful. I never could get the Aspen AOA calibrated correctly even after several tries and verifying the accuracy of the pitot system, but it was much more stable than the AV-20S. Someday I might install an Alpha Merlin on the glare shield. Skip

Does Mooney have stock? Probably very expensive, but if you need them NOW and they have stock, that might be the way to go.

If I were troubleshooting this, I would begin by disconnecting the LHS from the gear down annunciator. If the fault is in the LHS or its wiring, powering it down would likely have no effect on the gear warning circuit because they are separate circuits.

That would pop the gear actuator breaker rather than the gear warning breaker.

From Lycoming SI1009 CALENDAR TIME PERIOD TBO All engine models are to be overhauled within twelve (12) calendar years of the date they first entered service or of last overhaul. This calendar year time period TBO is to mitigate engine deterioration that occurs with age, including corrosion of metallic components and degradation of non-metallic components such as gaskets, seals, flexible hoses and fuel pump diaphragms. CAUTION CALENDAR YEAR TBO IS BASED ON ACCELERATED TESTING AND OVERALL FLEET SERVICE DATA. LOCAL CLIMATE CONDITIONS, STORAGE CONDITIONS, FREQUENT EXTENDED PERIODS OF INACTIVITY, PRESERVATION TECHNIQUES USED DURING INACTIVE PERIODS, AND FREQUENCY OF OIL CHANGES CAN AFFECT CORROSION OF METALS AND DEGRADATION OF NON-METALS.

The G5 works differently. The GMU 11 is optional for a stand alone G5, so the internal AHRS does not require and uses GPS and pitot-static only. Garmin does’t explain all the possible soft failure modes. That’s why I installed an AV-20S. All the jets have three attitude indicators and I wanted a tie breaker made by a different manufacturer that’s completely independent of any other systems. Probably overkill, but it was cheap and I sleep better knowing it’s there. I believe that’s true. If the engine instrumentation us critical, I believe the Garmin solution is a second GDU.

There are some clues here. If the airspeed switch is defective, you will get the warning horn immediately upon placing the gear switch in the up position, the adjacent red override button will illuminate and the gear will not move as evidenced by the floor indicator showing green alignment makes matching up. Since you indicate that you had the barber pole showing on the floor indicator and when you subsequently lowered the gear you got various indications of a normal extension, it seems that the gear did in fact retract. Therefore it is not the airspeed switch. The fact that you got an immediate warning when the gear switch was put in the up position points to a throttle switch. You said you also had a steady gear unsafe light on the annunciator which might also implicate the gear up limit switch. The problem will be apparent when you can jack the plane and investigate.

I believe that the Garmin Pilot gets EIS data from the G3X Bluetooth. Losing engine data is not a big issue for me in my J, but with a turbo it is more of a concern. The GTX 345 AHRS is disabled in a G3X installation. While the GTX outputs AHRS data on Bluetooth, the source is the G3X or G5 AHRS. The GSU AHRS, as all MEMS AHRS, uses various external inputs for aiding including the magnetometer data, pitot-static data, and the GPS navigator data. Garmin doesn't explain well what happens when one of these sources is degraded which is what you are apparently experiencing. I would discuss this with Garmin. I don't see an error message "AHRS magnetic anomaly" described in the Pilot's Guide, the Maintenance Manual or the Installation Manual, so perhaps it is pretty rare.

900 rpm is pretty high for an idle speed. I believe the spec for the K warm idle speed is 700 +/- 25 rpm.

Looks like someone removed the lower gear doors and the aft fairings.

Worn shock disks will not cause a mechanical retraction issue (They cause issues on airplanes with squat switches, but yours should have an airspeed safety switch). You can check the disks by putting in full fuel and measuring the gap between the top retaining plate above the disks and the collar on top of the center post that goes through the disks. Max gap is 0.6 in. (Ref Service Manual 32-81-00). The marks under your wing look to me to be where the MLG fairings should be. Has your plane been modified with the flush gear doors STC? Since the gear went up, it is probably not an issue with the airspeed safety switch. It sounds more like an issue with the up limit switch. The gear actuator is rated for 2000 lb so if the gear were hitting something I would think something would be noticeably bent.

Isn't the procedure in the POH full rich before landing? What's your warm idle speed?

You might check on the Bendix-King AeroCruise 230 (NOT the nonexistent 100). I believe a few of these have been installed. It uses the old servos, so it should be cheaper because you don’t have to replace servos and wiring. However, those servos are expensive to repair if they do go bad and they are getting old. And there is a question about the quality of B-K support. Garmin has excellent support for the GFC 500 and it is a great autopilot. Much of the autopilot software resides in the PFD so you need a G3X, G5s or GI 275s as part of the installation. Skip

I’m always suspicious of instrumentation and personally would not modify anything until I knew the instrumentation was accurate. In my case, when I put in the rebuilt engine in my M20J, I had the EDM 700 calibrated by the factory and installed all new JPI CHT probes. (Cylinder number 3 got a ring probe under the factory bayonet probe replacing the spark plug probe). Cylinder #2 ran 20 deg F hotter than the 1 and 4. Cyl 3 was lowest, but I expected that since the piggyback probe runs cooler. The baffle seals were new and all leaks had been plugged. When I replaced the EDM with a G3X/EIS, with the same CHT probes and wiring (except #3 which was replaced with a JPI bayonet), #2 fell in line with the others and is usually slightly cooler. To determine whether the fuel pressure problem is the gauge or the transducer, I would take the back-shell off the CPC connector which will allow you to get DVM probes on the wire end of the contacts with every thing connected. You can check the excitation voltage from the gauge ( (pins 1,2) which should be steady around 10 Vdc and the voltage from the transducer (pins 3,4) which should change depending on whether the boost pump is on or off and should be steady. If the excitation is missing, the gauge is bad. If the output voltage is missing, varies or is not different when the boost pump is on/off then the transducer is bad. Otherwise, it is a problem with the gauge. Of course, it’s always a good idea to check the wiring and especially the connectors. There is a CPC connector at the transducer, a cannon plug at the firewall, and a connector on the back of the instrument module. If the problem is the gauge, Sigma-Tek still repairs them. Skip

Mine was doing that also. The baffle presses against the mounting arm and the alternator case . We just put a bead of RTV in the places where it wants to make contact to cushion it.

I’m not sure how much good the stops do. When mine got damaged, the right tab broke clean off at the weld. It also bent the steering link. Interestingly, the dent in the tube was only about 1/32” which is the acceptable limit. I’ve seen pictures of tubes dented 1/3rd the diameter or more. I can’t imagine how much you have to oversteer it to do that.

There is no simple answer because there are too many variables. The major concern is corrosion. Was the airplane stored in Tucson or Palm Beach? Are the cylinders steel or chrome? Who did the overhaul? Does it have plain, DLC or roller lifters? When was the oil last changed? A thorough review of the logs and overhaul work order and complete inspection of the engine including borescope examination should provide enough information to a knowledgeable person to make a reasonable determination. Still, ALL used engines (and used airplanes, for that matter) are somewhat of a crapshoot. Good luck, and enjoy the adventure. Skip