Vance Harral

A mechanic friend called me today, who I'll keep anonymous because he is a truly good guy and everyone makes mistakes. He was working with an apprentice to swing the gear of an M20J as part of an annual inspection. The apprentice was in the cockpit and working the "lawnmower pull start" mechanism in the J model that manually extends the gear. Well, there wasn't quite enough supervision, and the apprentice kept pulling on the line even after the gear down light illuminated, until it got really hard to move. My guess is the bungee springs on the main rods are bottomed out, and the truss rods are in an excessively over-center position, but I haven't actually seen the airplane. Anyway, my mechanic friend says the gear is now "bound up" and won't move in either direction. In particular, if the system is put back in a normal configuration (tab closed, which is supposed to disengage the emergency spline, then breaker in), selecting gear up with the switch doesn't do anything except trip the breaker for the gear motor. In my M20F, the emergency extension crank can be rotated CCW to move the gear toward the retracted position. Yes, I know the placard in the cockpit says not to turn it that direction, but the M20F service manual actually prescribes doing exactly that during certain rigging operations. So if this was an F model, turning the emergency extension crank CCW might be a way to alleviate the over-extended scenario. But my limited understanding of the "lawnmower pull start" system in the J model is that it's impossible to do this. I can't offer much help to my friend because I'm just not really familiar with the J model emergency extension system, and it's unclear to me what might have actually happened to get the gear bound up like this. Supposedly none of the rods appear to be bent, the system is just under a lot of pressure. It occurs to me that the emergency extension spline may no longer be dis-engaging properly, and that's what's actually causing the breaker to trip rather than pressure on the gear rods. But again, I haven't seen the airplane. Anyone know how to get the gear moving back in the other direction, or at least release the pressure/tension on the mechanism? My friend is contemplating removing some of the bolts that hold the rods in place, but that seems like a bad idea when the system is under pressure, as it might damage parts and/or hurt someone.

This is one of those interesting cases where newer isn't a slam dunk. GI275s have higher resolution, brighter displays, and features the G5 doesn't. But whether having more, brighter pixels makes up for the physically smaller size of the display depends to some degree on individual eye performance: focus, whether you need cheaters, etc. Some people prefer the physically larger square displays over the higher resolution round ones. So make sure you go actually sit in airplanes with each flavor, before deciding. You can't really tell how it will affect you personally just from pictures. You only have to cut the panel for G5s if you want to flush mount them, and that's not a requirement, though you might have to file the hole slightly out of round to get a pair of them to sit one above the other (we did). But they stick out from the panel quite prodigiously if you don't flush mount - about 3/4". You don't really notice this sitting right in front of them, but it looks ugly from the side. If you're a flight instructor in the right seat, non-flush-mounted G5s also tend to obscure the tip of the steam gauge ASI needle when it's in the most interesting part of the range; and if you install only a G5 ADI and keep your steam gauge DG/HSI, the non-flush mount tends to obscure the top of the DG/HSI, which is of course almost the only thing you care about. Note that the airspeed and altitude tapes on the G5 are not certified primary, and thus are for "situational awareness only", the 275 is superior in this respect. But when I point this out with my flight instructor hat on, response from the pilot in the left seat is nearly always, "Yeah, whatever..." I know most of them are completely ignoring the steam gauge ASI/ALT, and it is what it is. When it comes to battery life, things get really curious. Garmin advertises 4 hours for the G5, but only 1 hour for the 275. 1 hour is "plenty" by a lot of people's standards, but if you're just comparing runtime, the G5 is the clear winner. My guess is that high-end display eats a lot of electrons. Here's a subtle point that's not obvious: the operational knob for the G5 is in the lower right-hand corner of the instrument, while the GI-275 is at lower left. In a "classic" Mooney 6-pack panel, the yoke shaft exits the panel right next to the 4 o'clock position of the lower center hole, which means the knob for a G5 HSI winds up right next to the yoke shaft, and that's an annoyance for us. Whether a lower-left or lower-right knob is better varies from airplane to airplane. Something to think about. Both devices are wonderful instruments and you can't go wrong with either. But as I said, not really a slam dunk to choose the newer GI-275, given the cost difference and the subtleties mentioned above.

The biggest issue with Cologuard is financial, at least if you use insurance for healthcare. Cologuard has a high false positive rate, about 13%. If your Cologuard test turns up positive, they send you for an actual colonoscopy, which often indicates there is nothing actually wrong. The problem is that at that point, your colonoscopy is no longer a "routine screening" that's covered at 100% by law. Instead, your insurer gets to decide how it's handled, and you typically pay your co-pay or deductible or whatever. That can run into the thousands if you're on a high deductible plan, see https://www.gastroconsa.com/how-cologuard-tests-may-end-up-costing-you-thousands/ I'm sure the people who developed Cologuard and the docs that suggest it mean well. It's a way to screen a percentage of the population too squeamish for the gold standard practice. But because of the way insurance works, it effectively looks like a big financial scam. Just go get the colonoscopy.

Here's the EGT routing on our IO-360, as of a few years ago. You'll note that the port side routing avoids the ignition wires, while the starboard side routing for the forward cylinder routes alongside the ignition wire and uses the same clamps. Like you, I never noticed any particular problem with data from the cylinder that ran along the ignition wire, and concluded it didn't really matter in practice. That said, the last time I had to replace a probe, I changed the starboard side routing to look like the port side routing and avoid the ignition wire. I don't really like the way the thermocouple wires just sorta hang loose in the breeze, but the wire is monostrand, stiff, and supports itself to some degree. I do think this "hanging in the breeze" arrangement likely contributed to a bunch of problems we had the first few years with the wires fatiguing at the crimps of the blade connectors that joined the pigtail from the probe to the connecting wire that goes to the engine monitor. I complained to E.I. about this and they claimed no one else had the same complaint as me. But then then they changed the type of connector they were using from a spade style to the "OLC" barrel connector, and our problems with wire fatigue have mostly gone away with those connectors. We've replaced several probes over the last ~16 years since engine monitor installation. They do have finite lifetimes. I think the "fast response" (smaller) probes don't last as long as the massives. They theoretically give better response, though. Our probes are further down the exhaust stack than any other installation I've ever seen. We just re-used the holes from an old analog 4-cylinder probe installation. They're further away than the installation manual for our engine monitor recommends, but having been in a bunch of different airplanes with different installations, I've come to the conclusion it just doesn't make any difference where the EGT probes are installed from a day-to-day operational perspective. Since absolute EGTs don't matter, and the numbers vary from airplane to airplane, it's not like you're trying to target any specific range of temps that make location critical. Hard to say what effect probe distance has on longevity - again we had poor luck with this before switching to the barrel style connectors, but that's a problem with the wiring, not the probes themselves. The conventional wisdom is that the closer they are to the cylinder, the higher the indicated temperature, and therefore the shorter the life. But I can't offer even anecdotal evidence that our probes are lasting longer than others' because they're further down.

Glad to hear from you, Andrew. Thanks for checking in with the community.

I think the risk of failure for a gear set that was properly inspected and lubed in the past 200 hours is quite low, and I don't lose any sleep over it. As discussed in other threads, though, the gear set really does wear out over time, even when properly inspected and lubed. That's the reason the lack of availability is so maddening. It's a little bit like being told the manufacturer of your airplane just isn't interested in the availability of brake pads or O-rings or oil filters, or other stuff that you are absolutely guaranteed to have to replace at some point. The long lifetime of the gear set compared to those other consumables makes it a slow-moving problem, but it's a problem nonetheless.

Your reasoning is logical, but that's not the way humans work. I've given about 1000 hours of instruction. That's not much compared to folks here with a lot more experience, but it's enough for me to have put a large number of pilots with varying experience in situations that make them slightly to largely uncomfortable, in a distracting environment. The idea that pilots will make a rational response to specific problems based on logic like you're stating here, just ain't true. I've seen pilots either lock up, or react "backwards" to all kinds of warning indicators: horns, buzzers, G-loads and so forth. And these are smart people who can tell you all the right answers on the ground over coffee. So I know based on what I've seen with my own eyes, that no one should take any comfort whatsoever from the idea they would "naturally" react properly to an unusual situation. The best you can do is actually induce the situation, and train for the recovery, until it hopefully becomes instinctual to do the right thing. Not instinctual because it's "logical", but just because it's what you did the last N times you actually experienced that situation, in training. Deliberately putting yourself in such situations with an instructor is reasonable for a certain class of problem: stalls, spiral divergence, etc. That's what Scott is doing in the video. There's another class of problem where it's not reasonable to deliberately put yourself in the situation in anything other than a simulator, e.g. engine failure immediately after takeoff. I try to get in the simulator to practice those sorts of things, but I don't do it as often as I should, and I don't suffer from any illusion that I'd be ice cool and always do the right thing in a pressure situation I've rarely or never experienced. I try my best to convince other pilots the same.

@gsxrpilot is alive and well, I had lunch with him this weekend. But like many folks (not yet including me for better or worse), he has decided that the less time he spends on social media, forums, etc. the better. Even if he was here, though, I doubt he'd have much to say about the 262. His airplane left the factory as a 252 which he updated to an Encore. As far as I know, he doesn't have any more insight into the 231 -> 262 conversion than I do, which is just we both know someone that had one. https://mooneyspace.com/topic/2181-comparison-of-mooney-252-and-mooney-262-conversion/ has a pretty good summary of the feature differences between the 262 and a "real" 252. But it's been so long since either was made, that most of the differences at this point are more about the individual airplane under consideration than the designed features. I think the increasing difficulty in obtaining "conventional" Mooney parts (landing gear parts, intake boots, etc.) is a much larger concern than anything associated with unique aspects of the various Mooney conversions like the 262, Rocket, etc.

The classic approach prescribes lacing for electrical wiring and Adel clamps for hoses and cables. That said, every mechanic I've ever spoken with about this says they use zip ties where reasonable. "Reasonable" is up to their judgement, like so many other things.

Splices are acceptable, but soldering them is contrary to the guidance in AC 43-13. The theory is that solder joints are brittle and likely to break, crimp splices less so. I'm not saying I necessarily subscribe to the theory, because I've had plenty of trouble with crimps. But that's the conventional wisdom, and the reason @PT20J - who I greatly respect for his practical experience - is directing you to use aircraft-grade butt splices. More importantly, you should generally be following the guidance in AC 43-13 as opposed to asking Some Guy On The Internet. 11-97 recommends replacing wire that has splices at less than 10-foot intervals unless for a specific reason, so yes it recommends replacing the whole wire even though it's a PIA and lots of mechanics ignore the advice in practice. The whole of Section 13 discusses splicing itself, where acceptable. It says there shouldn't be more than one splice in any single wire segment except in special circumstances. Section 13 also has guidance on acceptable lugs, including the tiny ring terminal on the CHT probe, which really is designed in accordance with industry guidance. FYI, other sections of AC 43-13 provide specific guidance to use "solderless" connectors, and discuss crimping extensively. The only places in AC 43-13 that mention soldering technique are in the context of pins that are mechanically supported in connector assemblies, and - interestingly - the use of solder in mechanical work rather than electrical.

The OEM CHT probe is a thermistor, not a thermocouple like modern engine monitors use. The good news about this is a thermistor just needs conventional aircraft-grade Tefzel wire, not mono-strand thermocouple wire. You can use the same type of wire for both the CHT probe and your landing light, though perhaps not the same gauge. Something like this should be fine: https://www.steinair.com/product/18-ga-white-mil-spec-wire/ Regarding gauge, the critical factor is to ensure the current carrying capacity of the wire is greater than the circuit breaker which protects it. The whole point of the circuit breaker is to ensure the wiring in the circuit doesn't overheat and catch fire. Here's a current capacity chart for Tefzel wire: https://www.prowireusa.com/tefzel-amperage-chart

I heartily endorse Aerodon's GMU11 mount! Worked perfectly to mount our GMU11 in the wing.

Stupid question from a vintage Mooney owner: why do the newer Mooneys have such deep "filler necks" in the first place, given all the grief they cause with actually filling the tank to capacity? I'm not near my airplane at the moment, but my recollection is that the structure that holds the fuel cap on my M20F is only trivially thicker than the wing skin itself. You don't read threads here on Mooneyspace about C/E/F/J owners trying to "burp" their tanks to get more fuel in, as so often comes up with the K/M/R/S/TN.

Obligatory pedantry from a high-density-altitude resident: manifold pressure at a specific throttle position changes with density altitude. So if you adjust the switch to trigger at, say, about 12" MP around your sea-level airport, it won't trigger above about 8" MP when approaching an airport that's 4000' higher than your home field. That means it might never trigger on a normal approach to that 4000' field. So... if you operate out of both high DA and low DA airports, your options are to have the switch trigger at annoyingly high MP, down low; or potentially not trigger when you need it, up high. We choose the former because of where our airplane is based, others might understandably choose the latter.

The 40:1 gears were installed as OEM equipment in later-model Mooneys with additional lower doors on the landing gear, and higher Vle/Vlo speeds. I presume they came from ITT, which was the manufacturer of the actuator at the time. They are not a "retrofit" in the sense of being special, one-off parts, manufactured specifically to address SB 190B. Rather, a case of using parts from a newer design in an older housing.