PT20J

FAA AIN https://www.asias.faa.gov/apex/f?p=100:96:1300354096487::::P96_ENTRY_DATE,P96_MAKE_NAME,P96_FATAL_FLG:20-JUN-24,MOONEY It's classified as an INCIDENT which means no substantial damage, but that can't be right. It also says that AIRCRAFT CONDUCTING TOUCH-AND-GOS AND VEERED OF (SIC) RUNWAY. That's not right either.

But, that never happens

The 20:1 / 40:1 ONLY applies to the Dukes (and similar ITT) actuators which use a worm and wheel gear arrangement. The problem with them is that the gears are small and heavily loaded. The moly grease helps reduce friction and thus wear, and the 40:1 retrofit gears are less heavily loaded than the original 20:1 gears to further reduce wear. Eventually the gears will wear out and there are currently no replacement parts available. The Eaton (a.k.a Avionics Products, Vickers) and the similar Plessey actuators use a spur gear train that is less heavily loaded and I have not heard of issues with gear wear on these actuators. The Mooney electric gear has no mechanical up locks. Something has to keep the gear from falling back down when in the retracted position. The worm and wheel gear arrangement cannot be back driven, so the Dukes/ITT actuators naturally hold the gear retracted. But the spur gear arrangement on the Eaton/Vickers actuator needs a brake which is the infamous noback spring. There have been a handful of noback spring failures in the field, most in Plessey actuators. There was one bad batch of Eaton noback springs that was recalled long ago and probably none exist in the field today. Don Maxwell told me that the Eaton noback spring is rated for 20,000 cycles. The 1000 hour replacement interval seems arbitrary and chosen because of a couple of failures or Plessey springs at around that time in service. But, time in service is meaningless. It is cycles that is important. Currently there are no new noback springs available. If it were my airplane, I'd keep the Vickers because I believe its a more robust design. It would also probably be a lot of work to source the parts and switch to the Dukes emergency retraction crank system.

I'm confused. Are those pictures of the Vickers that was removed and the Dukes you are considering installing? The Vickers in the picture is not a 20:1 gear actuator. It is a later model design as used in airplanes built after 1978. It has been built under various names: Avionics Products, Vickers, Eaton. It has a more robust gear train and has a noback spring and a completely different emergency gear extension mechanism than the Dukes. I believe that parts for the Dukes emergency gear extension system are difficult to obtain.

Hardly ever makes sense to buy a new engine. What's the lead time and cost on a factory rebuilt engine?

My two M20Js both required about 4 seconds of prime when cold. Make sure the throttle is open when priming - it affects the fuel flow when near idle.

Depending on the amount of corrosion, it is often more economical to replace the wing with a salvaged one.

I agree with @EricJ. If it was repaired correctly, it should be good as new. I think people make way too much fuss over damage history. These airplanes are old and stuff happens. Airplane sales are a negotiation between buyer and seller. Your case is special because you are selling a share to partners. If I were in your position, I would pay for one or more written appraisals and agree to sell your share for an amount based on the appraisals. Jimmy Garrison https://www.gmaxamericanaircraft.com/ would be a good place to start.

The cotter pin is way too long.

Single mags from Bendix and Slick are available with 15 degree lag angles, which means that when the mag is timed to the engine at 20 deg the impulse coupling will fire at 5 deg BTDC. The Bendix dual mag is not available in different lag angles and was designed for mag to engine timing of 25 deg BTDC. Here is the original Lycoming Service Instruction. SI 1325 Timing Change for IO-360 Series Engines.pdf Also, the note in the Operator's Manual begins, "On the following model engines..." The first engine listed is "IO-360-A Series (Except -A1B6D)". You have an -A3B6D. The difference between the 3 and the 1 is just the propeller indexing, so the parenthetical note applies to your engine. The D signifies dual mags.

Anything can be repaired. It’s a matter of time and money. It’s just like a car. Get in a major crash with a 20 year old car and the insurance company is going total it because the cost to repair exceeds the value of the vehicle.

The procedure is in the service manual. Essentially, loosen the screws, move the stall vane assembly, tighten the screws, test fly. Repeat until you get it correct.

Just to be clear, hearing the impulse click just means that the impulse coupling is working. The only way to tell that the mag is timed correctly is with a magneto synchronizer. When priming, the throttle position has an effect on fuel flow. It should be well open to make sure that the idle valve has fully opened the main jet. Then it should be closed to maybe a quarter inch open for starting. With two single mags, only one has the impulse coupling and so only one is firing for starting. The impulse coupling on the dual mag fires both mags, so it should start easier than with single mags. To take advantage of this, the ignition switch should be wired according to SIM20-59A. Did you get the mag maintenance done because something was wrong, or just because it was due? If nothing was wrong and it started fine before the mag work, I would suspect the mag maintenance. Maybe the E-gap is set wrong and the spark is weak.

A few comments: 1. There is no need to reduce rpm to 2600 during climb. It costs you about 10 hp and lengthens your climb. 2. The easiest technique for leaning in a climb is to note the EGT at takeoff and then lean during the climb to maintain that EGT. 3. There is no reason to worry about the exact value of EGT. It will never get hot enough in a normally aspirated engine to hurt anything. It's not even a real temperature, but it is instead the average of the pulses of much hotter exhaust gases that pass over the probe every time the exhaust valve opens. What is important is the relative value compared to the peak value. 4. At 65% power and peak EGT, an IO-360 burns about 9 gph. At 65% and best power mixture, it burns about 10 gph. 5. Lean of peak will produce lower power than you would get with the same MAP and rpm at richer mixtures. If you are operating at 11,500 feet LOP you will certainly burn less gas, but the airplane will be slow because the power will be low.

The ball joints are supposed to be fastened with AN3-16 bolts, washers, castle nuts, cotter pins and coil springs per the IPC. The springs hold the tension correctly. There is no torque since the bolt length is fixed and the nut is retained by the cotter pin. If the joint is too loose, it's because the springs have lost tension and should be replaced. The torque on the hanger isn't critical but if you really want to torque the bolts, just use the standard torque for each bolt size.

Without the rigging tools, how do you check the preload which is supposed to be checked as part of the annual inspection?

The dual mag can only be timed to 25 deg BTDC. Can you hear the impulse coupling click when you rotate the prop by hand? Was any other word done to the ignition or fuel system?

Two squelches: Noise squelch was factory set to 57 but works best at 0 to 10. Carrier squelch adjustment used to bottom out at 0 which is the factory setting. With the new software it can be set as low as -100. For most airplanes, 0 is fine. If your airplane is noisy RF-wise, a lower setting may help. The Beechtalk guys find -25 to be a good number for most applications. I long ago figured out to set the noise squelch to 0 and mine has been working fine and compares in sensitivity to the #2 which is a GNC 255. I didn't mess with the antenna or original RG-58 coax when I had the GTN 650Xi installed. I know that RG-400 is all the rage, and it is better coax being double shielded and slightly lower loss. But, I wasn't having any problems that required better shielding and at com frequencies for the short runs in the airplane, the loss difference is negligible. I'm a "don't mess with it if it's working" kind of guy .

Did they run a VSWR test on the antenna and cable, or are they just replacing it? Antennas are pretty simple devices. Not really a lot to go wrong and hard to see how it would kill the transmitter unless it was physically damaged causing a short or something. But @EricJ's likely more knowledgeable about antennas.

Any chance the GTX was powered up with the antenna disconnected? Running the GTX without the antenna (or a dummy load) connected can damage the power stage because it transmits Mode S acquisition squitter pulses once a second even if not receiving ground radar interrogations and with no antenna all the energy gets reflected back into the transmitter. This problem most often occurs during maintenance when a belly panel is removed and the antenna is then disconnected. My installer put a label on the coax at the antenna end reminding to pull the GTX circuit breaker if the antenna is disconnected. There is a caution about this in the GTX maintenance manual.

A split in rpm drop indicates that the mag timing is not the same for both mags. There are two timing parameters: internal timing (E-gap) and mag to engine timing. The problem is that unless you know the history of the mags (when overhauled, and how many times, and in what direction, the mags were "bumped" to change mag to engine timing) you don't really know which timing is incorrect. If the mags have less than 500 hours on them, you might just have your A&P check the timing and bump the mags as necessary to meet spec. If the internal timing is the source of the error, the worn mag will put out a weaker spark. I believe that the general rule is that mags can be bumped up to 5 degrees to compensate for internal timing being off. If the mags are approaching 500 hours I would probably just have them IRAN'd.

Thanks, Eric. Is there a clamp or just a ty-wrap hiding behind the #4 lower spark plug wire -- I can't quite make it out from the picture? Another interesting thing about my installation is that JPI suggests mounting the EGT probes 2-4" below the cylinder and mine are mounted 1-1/2" which I would think would be hotter and shorten their life but they soldiered on for 1500+ hours. Peak EGTs at about 65% are around 1450 deg F.

Now you're getting somewhere According to the Service Manual, the low voltage light should flash when the voltage drops to between 26.6 and 26.4 volts. The pot may need to be adjusted. A properly operating voltage regulator will drive the alternator to maintain the voltage at its sense input (which connects to a breaker on the panel) to whatever the regulator is set for. The voltage at the sense input may or may not be the same as voltages measured elsewhere in the system, but bus voltages measured at various points should be within a few tenths of a volt of each other. If the ammeter is showing positive charge, the alternator is working. If it's voltage output is low, it's likely an issue with a high resistance connection somewhere, worn out batteries drawing excessive charge current or a voltage regulator adjustment.

One of my JPI EGT probes is getting wonky and the wiring and connections check good. These probes have over 1500 hours on them (JPI claims 600-1000 hour life expectancy) so I'm going to replace them all. The original installer bundled the EGT/CHT wiring with the ignition wires which is not recommended by JPI, although I've never noticed a problem. But, since I am replacing them, I'd like to clean up the installation. Anyone have pictures of how your IO-360 EGT/CHT wires are routed to the cylinders?

3” extensions should be available from Mooney through any Mooney Service Center. You need two; one for each pilot’s pedal.