Vance Harral

In our stock M20F, the threaded hole does not extend into the tanks. This does indeed seem to be specific to the Monroy tanks.

"Nice time machine you've built there. You going to go back in time and invest in Apple? Nvidia?" "Nah. Mooney landing gear doughnuts".

Of course not, but the question is how much "gas in the tank" the pilot has left, cognitively, to perform tasks above and beyond what's required for the IPC. As you note, lots of pilots wind up getting an IPC signed off not because they need one, but essentially by coincidence. Such pilots are active, proficient, and able to accomplish all the tasks required for an IPC without being mentally taxed, and therefore can meaningfully accomplish more than the required items in a single flight (I wouldn't call the IPC task list just "basic minimum items", there is quite a lot there). And in almost all cases, such pilots don't actually "need" the IPC because they're already instrument current, and very likely to remain instrument current for the forseeable future just by conducting training and/or real-life operations that gets them the 6 approaches, holding, and intercept/track. For pilots like these, the concept of "getting an IPC" is really just shorthand for wanting a high level of proficiency training. Whether there is an IPC signoff in their logbook is academic. As you might guess, only a subset of the pilots who come to me for an IPC fall in this category. The others are rusty, trying to regain currency, and I'm just trying to do my best to give them the best odds at making use of their rating (and frankly, keeping them alive). If I press too hard on the idea that an IPC includes more than the bare minimum, most of these clients are entirely game for it, because they understand that the end result makes them a better pilot. You would think that's a good thing. But that's just theory. In practice, the result is sometimes that the "IPC plus" flight goes somewhat poorly, I never see them again, and I'm left to wonder if the net result was actually an overall decrease in safety.

It's helpful not to confuse an instrument proficiency check with instrument proficiency training. As @bigmo notes above, meeting the requirements of 61.57(d) for an IPC is specifically and legally tied to a list of tasks in the Instrument Rating ACS, and all of them must be covered. The instructor (and their client) get to choose how those tasks are covered, and you can of course add extra stuff. But there's something of a cultural expectation that a proficient IFR pilot can accomplish an IPC in one session. If you start getting too creative in that one session, you wind up with a fatigued pilot at the very far realistic corner of the unusual situation/emergency envelope. That's not necessary helpful to anyone, and it doesn't meet the spirit of law that requires the IPC in the first place. So I don't try to "pack" an IPC with much more than the ACS task list itself. When I conduct IPCs these days, really the only item of much discussion is how to conduct an "Approach with Loss of Primary Flight Instrument Indicators" in an airplane with redundant EFIS displays. This is increasingly the default situation, because even the most pedestrian IFR airplanes tend to have at least a dual G5 or similar. I have a couple of comments about that. First, I'm not opposed to pulling a circuit breaker. I'm aware of the guidance from Garmin not to do so, but you've got to understand what's behind that guidance, which is more about confusion of pilots, instructors, and maintenance personnel than it is about any damage to the expensive gizmos. I've written about this in other threads, so I won't go into it here except to say that an electrically powered device can certainly lose power, and pulling a breaker is a way to simulate that. Like all abnormal situations, it's best to experience this on occasion in training, so you can see how small things can be quite disruptive. e.g. most dual EFIS setups will revert the primary attitude display to the backup display if the primary display loses power. This is great, but I've found that pilots tend to underestimate just how distracting it is to have their primary attitude information in even a slightly different location, even though it's the same display. In the case of the smaller EFIS instruments like the G5/GI-275, they may also not realize how hard it is to do without an HSI, even though the primary ADI shows course guidance information (in a different manner) at the bottom. But all of those things are less distracting on the first attempt than abandoning everything in the panel in favor of Foreflight on an iPad. To be clear, Foreflight on an iPad is a reasonable backup plan, but you've got to practice with it. Anyway... having said that, I also like the technique of simply using backlight controls to dim an ADI display down to the point of it being invisible (working perfectly fine, you just can't see it). There are a couple of reasons I like this approach. One is that while we tend to be enamored of the "redundancy" of dual G5s or whatever, that redundancy only kicks in when a device loses its bus link to the other device - typically due to a complete loss of power. That is not the only - or I suspect even the most common - failure mode. It doesn't help you if the sensors feeding the device quit. Also, LCD backlights can definitely malfunction, and if they do, they don't fail in a way that a secondary display could detect. In addition to considering these "partial failure" scenarios, I also think the whole point of partial panel work is just to get the pilot used to the idea of using all available instrumentation to control the airplane when something goes wonky. It's not so much that you're trying to simulate a "realistic" failure, as it is that you want the pilot to be thinking about things like the fact that airspeed is a somewhat decent indicator of pitch (at a given power setting), GPS groundspeed is a somewhat decent indicator of airspeed, that a good old wet compass really does show heading, and that GPS track is a fine proxy for heading in all but the most extreme circumstances. That a standard rate turn as shown on an old TC really does change your heading 3 degrees per second, and so on. All of those things make you a better instrument pilot even in non-emergency situations, and the better you are individually, the better the system works for everyone. One of my airplane partners calls this sort of stuff "mental pushups", equating them to physical push-ups. We don't do push-ups because the push-up motion is something most of us often (or ever) need to do in real life. We do them because they help you be generally strong, and being generally strong is good for your overall health, even if the exercise that got you strong isn't directly applicable to your life. Once I started thinking of things this way, I got more creative about simulating failed equipment. Partly because it's fun and helps me learn more about the complex systems we fly these days. But also because it wholly and legitimately dismisses pointless fights over what is a "realistic" failure. The vast majority of pilots flying behind EFIS panels are - understandably - never going to be able to understand the nuances of all the possible failure modes. I can tell you that as a hardware/software engineer, even the people that design the systems can never completely guarantee they understand all the failure modes. If they can't, you can't. And if you can't, mental push-ups is the best strategy. But getting back to the original topic, this is not the sort of thing you knock out in a single IPC. Again, an instrument proficiency check is not instrument proficiency training.

In my experience that's not always practical. It's one thing to aggressively polish down a flat surface like a wing skin. Quite another if the stain has seeped into lap joints, non-flush rivets, and so forth. In those locations, you're likely not getting rid of the blue/brown stains without taking a wire brush down to bare metal and repainting a touch-up area. A combination of laziness and interest in preserving the protective value of the paint even if it looks awful, has left us with a number of blue/brown stains on the undersides of the wings. I'm watching these threads with great interest. We've been getting by with tolerating small seeps and making every-few-years patches on our original (1976) sealant. That got us through the ~20 years since we bought the airplane, and I don't regret the approach one bit. But the collection of small annoyances and increasing concern about getting to a patch facility in the event of a major breach, has led us to schedule our airplane with Don Maxwell for a full strip and reseal at the beginning of February. I'd like to think this is going to give us "new" sealant that's relatively impervious to whatever fuel achieves market leader status in the future, but time will tell. It's hard for me to worry about the paint for now, as the current paint job was not that great on day one (in 1990), and now has 35 years of wear-and-tear. G100UL is sort of a moot point for us in the near future, as there is none nearby: only 100LL at our home drome , and UL94 that we can't use at some other Colorado airports.

We did the light bulb thing for a while, but ultimately decided jamming a glass bulb in the engine compartment (even with the protection of a trouble light cage) skeeved us out. Now we put a small electric space heater under the cowl and direct the airflow up the cowl flap. It's not fast, but it's better than the light bulb, and seems less risky.

Uh... negative... multi-engine training aircraft do indeed spend a whole lot of time with the throttle pulled back and the prop windmilling. Almost all OEI training is done with the "dead" engine actually still operating - it's either windmilling at idle, or operating at a very low power setting ("zero thrust"), because it's considered good risk management to minimize the frequency and locations under which an engine is actually feathered for real. Power off stalls require a windmilling prop. Vmc demos require a windmilling prop. Emergency descents are always performed with both engines at full RPM and idle power, in a high speed descent. This sort of work happens every day, so it makes it hard to buy into the idea that prop-driving-the-engine is a high-risk concern (hard to worry about "shock cooling" too, but that's a separate subject). None of that takes away from your data point on your buddy's RV-6 with the broken rings, though. And again, the acute risks of multi-engine training are high enough that long-term engine management concerns might be dismissed even if they're real. I'm just trying to understand the physics.

That's exactly why I'm asking for details. I'm a relatively fresh multi-engine instructor. The nature of the training requires allowing the "prop to drive the engine" on essentially every flight. Nothing in any multi-engine training material I've ever read indicates this is a concern. To be fair, the concerns of an immediate emergency/loss of control/crash are so acute in that environment that probably no one worries about the longevity of the engine. A neuron fired, and I remembered this article from AvWeb a long time ago: https://www.avweb.com/features/pelicans-perch-78-props-driving-engines/. It seems to suggest that the issues with the location of the oil hole in the rod journals, torsional resonance, etc. are "real", but do not rise to the level of an operational concern except in radial-engine (master rod) powered airliners descending at very high speed out of the flight levels for very prolonged periods of time.

What, exactly, is the strain or wear mechanism in the prop/crankshaft train that makes this a concern?

Thanks for the complements. I'm willing to share our documents, but I first owe my partners the courtesy of getting their consent to send them to third parties. I'll ping them when I get a chance, it will take a few days. One thing I will say immediately is that it took us a while, but we finally figured out that one should have one simple document which addresses the business of the LLC and its members only in general terms, independent of what business the LLC might be engaged in (things like how shares are tracked, rules for meetings, etc.); and a separate and usually more complicated agreement that details how aircraft owned by the LLC are operated, maintained, and funded. Don't mix and match the two, as doing so winds up creating conflicting information and generally just becomes a headache.

That's the way our partnership works, and I was really enamored of the idea in the early years. I'm not disenamored with it now, but I also don't care about it as much as I used to. It turns out it that people who spend a lot of time advocating for this kind of thing are largely missing the forest for the trees. The majority of fuel bought will always be at the home airport, because any other strategy quickly runs afoul of the hourly cost just to fly the airplane to the airport with cheap gas. So pilots are only going to leverage this delta on cross-country flights. A really active partnership (not a flight school) might have partners who each fly 100 hours per year at roughly 10GPH. That's 1000 gallons of fuel per partner, most of which will be bought at home. Even if a partner with particular wanderlust buys fully half their fuel away from home, and manages to save or spend an absurd average delta of $2 per gallon, the resultant "savings" or "subsidy" vs. other partners is $1000 in this extreme example, and in reality it's much less - maybe a few hundred bucks. Compared with the cost of owning and operating the airplane in the first place - especially the uncertainly discussed above - this just isn't a whole lot of scratch. That's not to say it's not still a good idea. But when forming a partnership, you really want to look for cues about whether the individuals are more concerned about the health of the partnership and friendships, or more concerned about "getting their fair share". People who put a lot of energy into arguing about how wet rates aren't fair tend to be in the latter category, though that's of course not an absolute. Just my two cents.

No, but I think doing so is entirely reasonable for pilots with plenty of interest in avionics (which is most of us). A lot of this has to do with what kind of equipment is in the airplane now, and whether the partners are really interested in just maintaining that exact same capability (and style), vs. staying at some Xth percentile of avionics cache' in the community. The former can be done less expensively, but a lot of pilots would say the latter is the real definition of "maintaining the avionics". Basically, they'll acknowledge they don't need an upgrade every time something breaks, but in the end they can't really stand the thought of flying with yesteryear's panel. As a specific example, you can't get a GNS430 repaired any more, and some people interpret this to mean that if their unit breaks, they "must" at least install in an Avidyne 440 (at considerable cost), because there is "no other option". But there are always other options, e.g. accepting a prolonged period of time without an IFR certified GPS, while hunting around salvage yards for a serviceable old GNS430, the same way one might have to do for a serviceable fuel selector or intake boot or landing gear actuator. If you take the latter attitude, the old GNS430 in your airplane is merely a $3-5K time bomb, not a $10-20K one. You can make similar arguments about autopilots, engine monitors, etc. Heck, we're still maintaining our Brittain autopilot, and we're not the only ones. I understand the concern, and I think there is no way around this risk in certain cases, e.g. a Mooney with a non-WAAS G1000 panel is a major liability due to a combination of integration, and how the STC is held by Mooney. But most of us don't have these corner case panels, certainly not in the vintage birds. What's a little more perilous/expensive/frustrating is how the system can change out from underneath you in ways that are out of your control. When we bought our airplane in 2004, a transponder was a dull gizmo that we didn't think much about, and had no plans to ever upgrade. We didn't set aside separate funds for "transponder maintenance" any more than we did for tires. But we had to shell several thousand dollars out of pocket for a new transponder in 2019 in order to continue legally operating the airplane in the metro area where we live. That was an unexpected cost, essentially a "forced upgrade". One could make the same argument about VOR receivers in the future, or even transponders again (I'm waiting for the powers that be to dictate we must have ADS-B diversity antennas in the US). So putting specific dollars per hour into an avionics kitty is certainly fair, and I wouldn't avoid a partnership that did so. Long story short (too late), I think you should talk with your partners about what it really means to "maintain" avionics, since there's a much wider swath of opinions about it vs. maintaining O-rings, rod ends, brake pads, etc. In general, I'd say a partnership of scroungers doesn't need a separate avionics fund, while a partnership of panel junkies does, even if both partnerships start with exactly the same equipment in the panel. Excellent, this attitude will server a partnership nicely. I don't begrudge those who feel differently, I just wouldn't want to be partners with them. That sounds like a great number to me, as long as everyone understands that some annual inspections uncover discrepancies that must be addressed immediately and vary wildly in cost. Whether to attribute such things to "the annual" vs. "maintenance that was coincidentally performed at the annual" is a regular source of discussion in our partnership. It's always complicated (and kinda fun, actually), but one guideline we use to decide is if we feel the affected component broke or wore out due to use (flight time) or just age (calendar time). In our case, we have separate logical funds for fixed vs. operating expenses, but the fixed expenses include maintenance items in addition to things like hangar rent, insurance, etc. The annual inspection is itself a fixed expense, so it's not a stretch to say that certain things addressed at the annual are fixed expenses as well. A trivial example of this is fuel-cap O-rings, which you might replace on a 1 (rubber) or 5 (fluorosilicone) schedule at the annual, regardless of number of flight hours. Most of the sole owners browsing this thread have quit reading at this point, after rolling their eyes right out of their sockets that anyone in a partnership really agonizes over the bookkeeping of O-rings. But I trudge on... One of the most difficult things to figure out in a partnership is how the partners really feel about "banking" money. Of course you want a kitty, but you need to treat the partners like grownups, and not overdo it. Requiring partners to bank money toward future maintenance expenses reduces the risk of someone coming up short, but it also requires them to pay opportunity costs for things that might never happen. Everyone has (or should have) a limit beyond which they're not willing to give a corporation they're affiliated with an interest-free loan. Even if that corporation is made up of their friends and fellow airplane pilots.

We've run our partnership for 20 years as of 2024, and have tracked this kind of stuff pretty closely, but only the past couple of years are relevant looking forward. Regarding engine/prop reserve, there is no way to set an hourly assessment that ensures the kitty is fat enough to avoid out-of-pocket costs at overhaul time, because you have no way of knowing when the engine will actually need an overhaul. Because of this, we choose to bill an hourly value that tries to approximate the market depreciation on the airplane as more and more time is put on the engine, which presently seems to be about $20-$25 per hour. This is related to the cost of overhaul and recommended TBO, of course, but it's not exactly the same. More importantly, the hourly depreciation is the same regardless of whether the airplane has 600, 800, or 1000 hours on the engine when the new partners buy in. To relate it to your specific question, I'd say $45/hour is much too steep, because the airplane isn't worth $45 less every hour it gets flown. It sounds like you're getting that $45 number by dividing your guess at overhaul cost by (2000-600), such that over the next 1400 hours you'll build up enough reserve to overhaul the engine for no out-of-pocket cost. Again, though, you have no idea when the overhaul will be needed, so that's not a realistic financial model. Instead, all the partners have to share the risk that the engine will need a premature overhaul, and everyone is on the hook for a share of the out-of-pocket cost (they can also share in the windfall if the engine goes well beyond TBO before needing an overhaul). The only way this works is if the hourly rate is based on market depreciation per hour, not the estimated cost of a future overhaul divided by a wild guess at how many hours it will be before that happens. To each their own, but I would not buy into a partnership that required me to pay an "initial reserve" on the engine, unless my buy-in price discounted the value of the airplane by exactly the same amount as the initial reserve. It kinda sounds like you're trying to get the incoming partners to cover some of the cost of the first 600 hours of depreciation, even though you were the only person enjoying the use of the airplane during that time. Regarding non-engine maintenance reserve, ours is currently set at $20/hour, and that's been adequate to cover status-quo upkeep. But we do a lot of owner-assisted maintenance, and we're also pretty formal about the difference between "upkeep" vs. "upgrade". For example, when our vacuum attitude indicator timed out a few years back, everyone paid out of pocket for the G5 installation, we didn't claim that installation of a G5 was just "maintenance" of the vacuum AI. We're not going to "maintain" our UBG-16 engine monitor by installing a GI-275 EIS when it malfunctions, or install a 201 windshield when the stock windshield gets too scratched up, and so on. If you choose to approach things this way, there is really no difference between the maintenance kitty for avionics vs. the maintenance kitty for tires, shock disks, heim joints, and so on. Things are maintained by replacing them with exactly the same thing. Anything different is an upgrade, subject to whatever voting procedures you use for upgrades. You didn't mention fuel costs, and that implies you plan on dry rates. Based on experience, I'd like to suggest you consider wet rates instead, that get adjusted a few times a year as fuel cost varies. I know this sounds like more trouble than a dry rate, but I think what most people miss is that it's simply not possible for every partner to always exactly replace the fuel they use at the end of a flight. Sometimes the fuel pump doesn't work the day you get home, and you're not able to drive back out to the airport the next morning to gas up. Other times one partner might ask another to deliberately leave the airplane down on gas so as to carry more payload, etc. In a wet-rate partnership, partners are simply reimbursed by the LLC for whatever fuel they buy, under any circumstances. In a dry rate partnership, events like the ones I mentioned create debts directly between partners rather than through the LLC, and that can lead to hard feelings. A wet hourly rate does deprive frugal partners of the opportunity to save money by gassing up at cheap airports and/or flying at reduced power, but the actual value of those savings is trivial in the scheme of overall airplane ownership, and in my opinion not worth the stress and risk to the partnership of creating fuel debts between partners. Finally, a word of advice: "add-on" partnerships like the one you're proposing sometimes fail because the previously sole owner never really treats the new partners like equals when it comes to how the airplane is operated. You've got to be at peace with the idea that you're *selling* the airplane, not merely lending it. On day 1 of the partnership, the new partners have a fully equal vote on how much gas to leave in the tanks, whether the airplane gets wiped down after every flight, how the seatbelts are stowed, what oil level to run at, whether the tow bar is left on the nose gear in the hangar or stowed in the baggage compartment, and so on. You need to avoid the feeling that you've got the airplane all figured out, and you'll teach the new partners how to operate it, and that can be pretty difficult. Regarding number of partners, we've had 3 or 4 at various times throughout the partnership, and that has indeed been a magic number for us. But... none of the partners fly overnight trips very often. Maybe 1-2 per year per partner. Obviously 4 partners isn't going to work very well if each partner wants to have the airplane away from its home base 90 days per year. That said, it's also worth noting that many people who buy into a partnership fly less than they planned/hoped, especially if it's their first airplane. I'm unconcerned when new partners approach our partnership stating they're going to fly 100+ hours per year, because I know that historically, most of them fly a little less than that the first year, and even less in the years after that. That knowledge makes it easy to be generous with scheduling. Most people are decent, and aren't going to take advantage in the long run, so you can build a really great partnership by being generous with scheduling and operating policies to your new partners in the early going. You might be a little annoyed that they don't put the airplane away the same way as you, but that seems pretty trivial in the long run when you build a great friendship, and every unexpected cost is split across the partnership rather than borne by you alone. Best of luck with your plans!

@amekler there may not be anything really wrong with yours. The intensity of the display is controlled by a potentiometer. Over time, with vibration of the panel, dirt, etc., this potentiometer can lose slider contact, resulting in the display intensity going to full bright or full dim. Simply wiggling the potentiometer back and forth a bit can often re-establish contact and restore reasonable intensity. We have had exactly the same problem as you, and I was able to resolve in just a few minutes with a small screwdriver. Instructions from the installation/maintenance manual are shown below. Suggest you slide the box out of the panel, tweak the display potentiometer a little, and re-install. It can't hurt, and might help.

I hesitate to say this in public, but after posting and asking questions like this about the oil stains on our gear doors and exhaust tunnels for years, our long-standing mechanic finally said to me one day, "Son, you need to either overhaul the engine, or lower your standards." Certain oil leaks that are benign from a safety perspective, simply cannot be fixed without maintenance that is just as likely to cause serious problems as it is to fix the annoyance of the oil leak. In our case, the main source of the leaking oil is the gasket seal on the oil pan, which is quite long in the tooth. This could definitely be addressed without an engine overhaul, but it would require removing the oil pan, which first requires removing the exhaust, which first requires removing the lower cowl, and so on. All of that could generate more serious problems. A bit of leaking comes from the rubber couplings on our oil drainback tubes, as @Yetti notes. When this first started, we tightened the hose clamps a bit and got it to seal, but eventually the rubber got pretty brittle, and it's more or less impossible to keep it bone dry without replacing the couplings - which maybe can be done without removing exhaust and/or induction tubes, but it's a pain. We have a couple of pushrod tubes that leak chronically at the seal near the cylinder head. The gaskets have been replaced multiple times, but they continue to seep. When we had cork valve cover gaskets, they'd start seeping after a year or two, though that's gotten better with the silicone gaskets. Sometimes seeping oil comes from a blown main seal at the crankshaft. We do check for this, and address it when found. But it's not really a critical airworthiness issue, and the prop has to come off to address it. One time the mechanic who removed the prop showed me how the previous mechanic to remove the prop botched the prop bolt safety wiring on re-installation. We do wash the engine at every annual, inspect for oil seeps at the crankcase seam and cylinder attach bolts, look for cracks in the case, etc. More importantly, we try pretty hard to wipe the oil off after each flight, so that we're starting from a relatively clean state, and can check after the flight to see if the amount of oil on the gear doors and exhaust tunnel is "normal". Bottom line, I've come to accept that while we'd all like a bone-dry engine, the design of the engines we fly isn't really conducive to staying dry through thousands of hours and dozens of years. Most of the Lycoming/Continental engines I see in the shop and on the ramp leak some amount of oil - particularly flight school airplanes and those flown for hire. For better or worse, I've abandoned the dream of a dry engine... at least until overhaul time.