Vance Harral

While I wasn't on the team that determined the restricted RPM range, I've been involved in similar efforts. The kind of engineering analysis that goes into this sort of thing almost certainly included guard-banding to account for tachometer accuracy and precision characteristics. Furthermore, the nature of the concern is long-term cumulative effect, so it's not like 2351 RPM is OK forever and 2350 RPM is immediately catastrophic. Putting those two thing together, it really doesn't matter which tachometer you reference to comply with the restricted range, unless one of them is grossly off by hundreds of RPM and therefore is not even airworthy.

Thanks very much, Clarence. This pointed me in the right direction to buy an assortment of MS20426AD rivets, and some Cleco fasteners as well.

As mentioned above, we'll need to re-do our seal this spring. I believe LASAR has the seal itself and plan to order from them. Last time I did this, we were at a "big" shop that had a giant bin of rivets of all sizes, and the mechanic working on our airplane handed me appropriate ones to use. I didn't note the actual diameter or part number. This time, we're doing our annual with an independent mechanic who has plenty of conventional supplies, but I want to make sure we have the correct rivets. The IPC doesn't specifically list what size rivet to use when assembling the "sandwich" of plates and the seal. Can anyone give me a pointer to a specific rivet part number, or a kit of assorted rivets that's likely to have the correct size?

Having operated an aging engine with an assortment of minor oil leaks for years, I'll opine two things: The amount of oil you're seeing is not even remotely close to a safety concern, though I appreciate that it's annoying, and it would be nice to know where it's coming from. In an airplane that actually gets flown, there is very little correlation between where oil is leaking from, and where it winds up inside the cowl. If you really want to know where an oil leak is coming from, you have completely and meticulously wash the engine with a degreaser, then try one of the tricks that identifies leak spots: foot powder, talc, UV dye in the oil, etc. I'm not saying it's not coming from the breather tube and the "whistle slot" hole that's intended to keep it from freezing shut. But the fact that tube is in the vicinity of the drips on your cowl cheek panel isn't very strong evidence for that particular hypothesis.

That's for the Xi line. I suspect the OP is talking about the OG GTN line, not the Xi.

At the risk of being disrespectful, I'm always puzzled by posts like this on airplane and car and RV forums and what have you. The OP's airplane looks very nice, but it's not like it's some one-of-a-kind special case, for which no comparables can be found. There are six M20Es up for sale on Trade-a-plane right now, a few of which are very similar matches for the OP's airplane: https://www.trade-a-plane.com/search?make=MOONEY&model_group=MOONEY+M20+SERIES&model=M20E&s-type=aircraft. Yeah, there's a flip job there listed at $179K with literally brand new paint and full glass; but if you throw out the top and bottom outliers, the remaining rational listings are in the $80-85K range. It took about three minutes of research to determine this. Anyone who is serious about selling their airplane could spend an hour or so on TAP and Controller, and a few other spots, and get a very good idea of the current market. It's fine to feel one's own property is "special", I guess. I also think people sometimes post these things not because they're serious about selling, but because they want to be told something that makes them feel good about ownership. But the bottom line is that anyone looking to buy a high-value asset is going to look at easily-accessible for-sale sites to see what's available at what price, so that's where sellers should go as well. Works for houses, cars, RVs, motorcycles, etc, unless your asset is truly one of a kind. Which - again with respect - the OP's airplane is not. Ignoring that and instead asking enthusiasts on an internet forum "what do you think it's worth?" just seems like a strange way to go about things. Feel free to tell me different, but I just don't get it.

Our Lycoming IO-360-A1A engine was last overhauled about the same time as yours - over 30 years ago. Currently at about 2400 hours since last overhaul. Different engine, but basically the same pushrod and seal geometry. We purchased the airplane in 2004 and two of the 8 pushrod seals have basically always dribbled a little oil in the ensuing 19 years. It runs down through the cylinder fins and shows up lower in the engine compartment. We've replaced the seals multiple times in an attempt get the dribbling to stop, trying both the original rubber gaskets, and some newer, fancy fluorosilicone seals. It helped, but we never got things completely dry. I finally decided to just stop worrying about it. In speaking with a number of owners like you and I, who choose to operate engines for decades since the last overhaul, I have yet to find a single such owner with a "dry" engine. They all have some degree of minor oil leaks, which the owners choose to tolerate. I'm convinced such leaks from pushrod seals, drainback tubes, the oil pan, and even in some cases around the case halves is simply not a serious risk. It can, however, mask a new leak from somewhere else that is a larger concern. That's the only thing that gives me pause about it.

I briefly glanced at this. Best as I can tell, the SAIB references an SI which just says, "Don't skip the landing gear inspection items on the 100 hour checklist". I get that the FAA and manufacturers periodically issue these things, to try to get operators and maintainers to, you know, actually follow factory guidance when they feel like it's getting neglected. But this seems like a nothing burger - people that are serious about maintenance already do these things, and those that aren't don't care about SAIBs and SIs. What am I missing, if anything?

With all this talk of people who won't fly IMC without various forms of backup, I'll throw in my pet peeve: pilots who don't actually train with their backup tools. For me, if we're actually going into the clouds, I'm open to all kinds of backup strategies. But I want to know that either myself or the person with their hands on the controls has actually used their backup AI at some point. Every time I do instrument training, I make it a point to get the student to actually fly with their backup. It's often an interesting exercise - many of them find it to be much more distracting than they thought to reference a perfectly good attitude indicator that's just not in the spot they're used to seeing it. Even in the now ubiquitous dual G5/GI-275 setups, where the backup is only a couple of inches away, the error rate is pretty high until they settle in to a new scan pattern. I wouldn't want to be doing it for the first time in IMC. But I certainly run across people who are primed to do just that - they're very proud of their backup strategy, but then I find out they've never actually used it to fly for a full 20-30 minutes and shoot an approach. I'm more liberal than Don about what I'll go into IMC with, but certainly respect his position. Everyone has their personal concerns, myself included. Mine is that I consider a portable AHRS and a iPad to be a pretty sketchy backup, not really adequate for hard IMC. As I said, I make my instrument students (and myself) fly with backup, and I've seen the portable solutions go south too many times to trust them. Sometimes it's the grossly comedic suction cup failure, where the AHRS hardware literally tumbles off its mount. But what's much creepier to me is that I've seen at least two Stratus/Stratux/Sentry devices just wander around in roll (a little) and pitch (a lot), even when firmly secured in place. I don't know what causes this, but I hypothesize that it has to do with the fact that all these inexpensive MEMS gyros devices need aiding to be accurate, and whatever aiding is built in to the portables just isn't is good and/or has more trouble with vibration and flexing given their ad-hoc mounting mechanisms. Throw in the fact that the tablet typically used to display attitude is down on the yoke, or over near the window or whatever, and the performance I observe from those doing the flying is commonly quite bad. Again, at least until they settle in, get used to any glitching, etc. Whatever your backup strategy, if you fly IMC you should be training often; and if you're training often, try to do it fully 50% of the time with your backup AI.

The G5 has no A429 inputs. If you have a GAD29B - which many installations do - you can send A429 data to that, and it will convert to CANBUS and pass it along to the G5. This works in the other direction too - e.g. our GTN gets air data from the G5 on A429 inputs - but this only works because the GAD29B is there to bridge the two busses. I don't mean to be a pedant about it - it's not really incorrect to say a G5 can get temp data "via A429". But for people trying to decide what they want and how much it's going to cost, it's important to understand the architecture. A G5 has an RS-232 interface for GPS position data, and CANBUS for everything else. Accordingly, any air data device that doesn't natively speak CANBUS will need a GAD bridge to communicate with the G5.

The G5 is primarily a CANBUS device, so any temperature data it receives has to be transmitted over that network. The main reason it can't get temperature data from existing probes is that those probes and/or the devices they connect to don't have a CANBUS interface to talk to the G5. The probes themselves aren't CANBUS devices either, but Garmin provides the GAD13 device to bridge analog temperature probe data to the CANBUS network. It's technically possible you could gang an existing temperature probe in parallel to a GAD13 and whatever it normally talks to; but I don't know the impedance implications of that, and you're into experimental territory anyway. As others have pointed out, you probably don't need an additional GPS antenna to install a G5 or two. They have a coax connector for an antenna, but they can also be set up to receive location data from a WAAS navigator over an RS-232 connection (which is independent from the CANBUS interface), and the latter is how most are installed. The other curious trick is that in many installations, the GPS receiver in a G5 will acquire satellites even with no antenna attached to the coax connection on the back. The installation manual doesn't allow exploiting this in a certified installation, but it's interesting. We have the temperature probe in our G5 installation, so we get OAT, density altitude, TAS, winds aloft, etc. It's kind of a fun gimmick, but I wouldn't agonize over adding the OAT probe if you don't have one. What I've found in practice is that the TAS and winds aloft are only accurate during a long, steady state experiment. It tends to be inaccurate when maneuvering (my guess is it's displaying a weighted average of samples over time). So it's frankly not that much help for tactical things like picking a wind correction angle in a holding pattern or approach leg. You can do just as well with GPS ground speed and ground track. Seeing density altitude while taxiing out is kind of cute. But pilots smart enough to understand the implications of DA already know the DA from math and/or the ubiquitous AWOS warnings. The G5 doesn't display the DA in flight (at least not by default), so it's not going to help you understand the likelihood of getting over a tall rock. I don't regret the extra time and effort of installing the OAT probe, but with a few hours under our belts flying with it, it just turns out that like many of these things, it doesn't really make an operational difference.

This is almost certainly a case of misunderstood communication. If you're being asked what a part 61 or part 91 regulation actually says, then sure, the appropriate reference is the actual published regulation. No DPE is going to accept you getting on Mooneyspace and pointing to a thread where redbaron1982 explains IFR currency rules, for example. If, on the other hand, you're being asked about atmospheric stability, or how an attitude gyro works, or any number of other things explicitly covered in the ACS which are not mentioned at all in the FAR/AIM; it would be absurd to say, "you can only use the FAR/AIM as a reference". Obviously I haven't met every DPE, and the system is notorious for individual DPEs having personal policies that aren't backed by any actual FAA policy. But I've met several, and none of them have this ridiculous policy that only the FAR/AIM can be used as a reference.

Our '76F originally had the SoS box mounted on the cabin side of the firewall. The last time an A&P/IA worked on it (about 10 years ago), he determined that was a stupid location, and he moved it to the engine side, right above the heater inlet. It's the red box at the lower left of the attached photo. I was a little taken aback by the move, as the mechanic didn't ask us about it before doing so. Apparently it was just obvious to him that it should be moved. A "minor mod" in his eyes, and documented, so the legal box is checked. Certainly easier to work on now, but that hasn't actually happened - it's been happily doing its thing with no issues ever since. If nothing else, that's anecdotal evidence that the new location is no worse than original.

To be clear, I wouldn't balk at buying an airplane whose logs simply say this A/D is not applicable by serial number, and I doubt many others would either. In our case, though, our A&P is coming out anyway to inspect the overhauled fuel pump we're installing, so it's kind of a no-brainer to have him take a quick look and note in the logbook that the airplane was inspected for bad elevator counterweights as well. You could do that at your next annual if you choose and it probably wouldn't cost you anything extra. I'd feel differently about asking an A&P to perform a formal inspection if doing so required disassembling anything, but it doesn't in this case - a quick look is sufficient. As an example of what I'm getting at, though... would you feel comfortable buying my airplane if you reviewed its logs and saw the electric landing gear actuator had never been disassembled and inspected for worn gears? None of SB M20-190B or AD 75-04-09 or AD 75-23-04 apply to our airplane, because neither its serial number nor the ITT LA11C2114 actuator installed in it are on any of the callout lists in those documents. If you ask around though, most Mooney-savvy shops and owners would tell you it would be foolish not to at least occasionally inspect the actuator, and that you should be skeptical of buying an airplane that's never had the inspection done. If anyone is going to perform that inspection, you should probably have them log it, whether the AD is truly applicable or not. My attitude toward this new elevator counterweight AD is similar.

Correct, Mooney/the FAA is worried elevators from the affected models may have been installed on other airplanes. Dunno if hybrid weights can be installed on beaded-skin elevators, but I wonder if anyone ever replaced a damaged beaded-skin elevator with a salvaged smooth-skin elevator, via 337 (or just not asking questions they don't want answers to). Our airplane - like yours - has the beaded skin elevators, not smooth. But I'm going to have a friendly A&P sign off an AD inspection anyway. Given the weasel words in the associated SB, I just don't want to get into an argument with some future buyer or IA who thinks the AD inspection should have been performed. Easier to just point to the logbook entry and say, "Yes, this airplane has been inspected in accordance with that AD".

No argument there, but the OP wanted to retain his KI-209. If the KI-209 is removed (or just bypassed and disabled), and the KX-155 connected directly to the GI-275 instead, that would certainly work, and eliminates the mechanical switch. Fair point that there's no drawing which shows a GI-275 driving analog autopilot deviation signals to a switch instead of directly to an autopilot. I hypothesize a good avionics shop or freelancer might be comfortable claiming the GI-275's deviation outputs are just an "omni output" in accordance with older autopilot installation manuals - since they conform to the analog voltage standard - and therefore pronouncing it kosher to connect them to an approved autopilot via a completely passive switch that presents an equal or higher impedance load to the GI-275 under all conditions. Driving two CDIs from a KX-155 seems a little sketchier, and I hypothesize fewer installers would put their name on something like that. But it's not my opinion that matters. These are good questions for the OP to ask an installer.

If the goal is to run the autopilot from NAV2, seems like the simpler and better way to achieve it is to just install a DPDT switch that selects between the GI-275 and KI-209 analog deviation wire pairs, for the autopilot's deviation inputs. Label it "autopilot nav source". Set to NAV1 for IFD-540/GI-275, NAV2 for KX-155/KI-209. This sort of setup used to be common, e.g. our old Brittain autopilot setup has a NAV 1/2 select. You don't say what autopilot you have, but if it's a somewhat older model, the installation manual almost certainly contains provisions for a nav input select like this. Materials cost would be a few bucks for the switch and a couple feet of 22AWG wire. Probably less than 1 hour of labor to install, modulo the usual "Mooney tax" for difficulty accessing stuff behind the panel. The only downside is that the switch becomes a potential failure point, so spend a few bucks extra for a high-MTBF unit. Based on what N231BN says, sounds like it's technically possible to drive two CDIs from a single KX-155. But I still think the pilot interface for that is confusing, and the potential for error high (you say you don't intend to set the OBS knobs differently on the two indicators, but sooner or later that will happen). Note also that you may or may not get an avionics shop to agree to perform the work. Some shops won't install anything on a certified airplane for which there is a not a specific drawing in the installation manual for the devices being connected, and there aren't any "dual CDI output" drawings for nav radios.

Without looking at the installation manuals, I'm going to opine that you don't want to do this, because the KI-206 and GI-275 have independent OBS "knobs" (physical in the case of the KI-106, virtual for the GI-275). Not sure what you're expecting to see on dual CDIs driven from the same source, if they don't have the same OBS knob setting. Lots of potential for confusion and failure, and seems like a bad idea.

Based on the picture you posted, your M20F is the same vintage as ours, with the early-J-style "6-pack" (actually 8-pack) round instruments panel. Having just finished a dual G5 installation in our airplane last month, during which we removed a GI-106A CDI indicator, here are some tidbits for your consideration: First, yes, dual G5s will fit in that panel. If you cut a whole new panel, you can do almost anything you want, including flush-mounting dual G5s, shifting them slightly, whatever. If you don't, though, you'll need to slightly file out the AI and DG holes of your existing panel to fit both G5s. This procedure is described in the installation manual, and isn't too a big deal. But per the manual, if you oval out the mounting holes this way, you're also supposed to buy or fabricate a couple of aluminum plates to more securely hold the instruments, as well as installing a slightly longer capture screw in the G5 unit itself. Post-installation, we've realized the push/twist control knob for the lower G5 HSI is close enough to the yoke shaft that it's a bit awkward to use with one's right hand. Easier if you reach over with the left hand, but that also feels a bit awkward to this right-handed bloke. That's a very minor gripe, though - absolutely not a deal killer. A G5 HSI can only display vertical/lateral needles for once source at a time. However, it can receive nav data from multiple ARINC-429-capable sources, via the GAD29B that is usually installed with it. If you have two "modern" NAV/GPS radios (e.g. Garmin 430W or better), you can switch the HSI display between them, and/or display bearing pointers for a secondary source while showing needles for the primary source. Whether or not this is a good idea is debatable. Personally, I prefer separate indicators. On a related note, I kinda miss the dedicated OBS knob of the GI-106A we removed. Setting an OBS course on a G5 HSI requires a "click-twist-click-twist" action, rather than a single twist. People who only navigate using GPS waypoint sequencing won't care about this. I only miss it because I'm old, and I like to pull CFI tricks on instrument students that require VOR navigation and/or OBS mode on the GPS. G5 vs. GI-275 is debated frequently. Not a slam dunk either way, IMO. My causal observation is that cost aside, guys with good eyesight favor the higher resolution display of the GI-275; while those not so blessed have a slight preference for the physically larger display of the G5, even though it has fewer pixels. Hope that helps.

ADs are no longer mailed to aircraft owners, though that used to happen. As I understand it, in the modern era, you're expected to sign up for e-mail notifications at https://public.govdelivery.com/accounts/USFAARGL/subscriber/new?pop=t. I believe the FAA's position is that failure to do so is a violation of https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-39/section-39.7. Please note that I'm not arguing this is a reasonable position for the FAA to take, just explaining my understanding. In practice, being a member of your aircraft's "type club" is usually sufficient to be informed. Regularly checking here on Mooneyspace is in certainly in the spirit of that.

Internet says GNX375 is 10.85" deep with backshell connectors. That is definitely not going to fit at the top of an M20J panel as depicted in the OP's layout. As carusoam says, the center tube that comes down the windshield branches out just below the glareshield, and winds up running behind the left radio stack in a manner that limits the depth of avionics that can be placed at the top of that stack. You are going to have to put that GNX375 either below the G3X 7" display (if it will fit below it), or over in the right side stack.

Again, thanks for all the replies so far. For what it's worth regarding the recommendations to use C&J, we did attempt to contact them for a quote, but they have not returned our phone call in almost 2 full business days. Further discussion with Aeromotors reveals they can also provide us with fresh leather washers and O-rings for the attach fittings (see https://mooneyspace.com/topic/41467-fuel-line-gasket-an6291-6-or-alternative/), so Aeromotors remains our plan.

Thanks for the replies so far. We called Aeromotors. They don't have any exchange units in stock, but their quoted price to overhaul our existing unit is the best we've found so far. They also have authorization to make internal components (including armatures), unlike some other overhaulers; and returned units come with an 8130-3. So that's likely the way we'll go, unless someone else reports something clever here.

Airplane exhibited the classic "dripping from the fuel pump weep port" this week. The crummy thing only gave us 19 years of service before the internal seals failed. Our airplane was "upgraded" from the original Dukes pump to the Weldon 8163A per a Mooney factory drawing, back in 2004. As a partnership with a maintenance fund, our preference is to purchase new, or overhaul/exchange Weldon, to minimize down time. Trouble is, looks like another round of old airplane/supply chain issues/whatever. Aircraft Spruce says no stock until April. Air Power says no stock until "probably" March. Backordered at Aviation Parts Executive. No luck at McFarlane or LASAR, though everybody is "checking on it". We're waiting on a call back from Weldon themselves, but I don't expect that to bear fruit. Haven't looked into going back to the Dukes pump - not particularly inclined to, but might consider it. Anyway, it's looking more and more like our best option is to send off our existing pump to one of the overhaul shops: Aeromotors or QAA, but that's a 3-ish week turnaround time, and we were hoping for something more like instant gratification. Anyone got any leads? If not, anyone have any contradictory recommendations to Aeromotors, which in searching old threads seems to be the most popular overhauler?

Same for me, for what that's worth. My most recent experience took nearly 3 full weeks to get a reply on the topic I mentioned above about "true heading". To be fair, this took place leading up to and over the Christmas holidays.