Vance Harral

What I'm getting at is that each revision of G5 software is associated with a set of documents. i.e. when you go to https://support.garmin.com/en-US/?partNumber=K10-00280-01&tab=manuals, you must select a specific version of software to get the corresponding documents. If you upgrade your G5 software, you're definitely supposed to print the AFMS associated with the new version of software and put it in your POH/AFM, and I think we'd all agree that makes sense. But I don't know what to make of corresponding changes in the installation manual. For the sake of discussion, let's say your G5s were installed with software revision 4.0 in 2017. That installation would have been associated with installation manual rev. 9, and maybe has both units on the primary bus. If you finally get around to installing software revision 8.0 this month, that's associated with installation manual rev. 29. Because of that, the rev 8.0 software could, theoretically, contain code that assumes the dual G5s are installed on separate primary/avionics busses. But your airplane isn't going to be wired that way unless you update your wiring. I'm not suggesting there's any kind of "real" problem here, and I don't think anyone should lose sleep over it. It just piques my interest because I'm involved in a line of work that has similar hardware/software/manual versioning concerns.

Yes, though interestingly, the requirement for the ADI and HSI to be on different busses didn't show up until later revisions of the G5 installation manual. Specifically, that requirement is found in rev. 17 of the G5 installation manual, but not in rev. 13. I can't find any copies of the revisions in-between those two, but the revision notes in rev. 17 cover back through rev. 13, and yet don't make any note of the power distribution requirements. Seems like this requirement was sorta "slid in" to the manual without any fanfare. Anyway, if you get in an airplane with dual G5s and they both power up on the main bus, that doesn't necessarily mean the installer didn't follow the manual. It may have been installed in accordance with an earlier manual. It's not entirely clear to me if you can legally update the G5 software in such an installation without re-wiring the power distribution, but that's a nitpick, and I'm certainly not going to hassle anyone about it.

The G5 ADAHRS works fine without a magnetometer, as evidenced by the fact that a single G5 ADI installation doesn't require the magnetometer. Once you've got the magnetometer, though, you don't want to try to disconnect it from either G5. The reason is that all this stuff talks to each other through a CANBUS backbone. If you remove the CANBUS connection from your G5 ADI, then in addition to losing the magnetometer data, you'll also lose the CDI display, and the mechanism that allows one G5 to detect the other has failed.

It appears the OP had the G5 ADI originally, and recently added the HSI, and is now missing the way track was displayed on the ADI. We had this same experience. The short answer is, you still have track information on the ADI, it's just not as prominent. It's the little tiny magenta triangle in the top "tape", shown at 290 degrees in the picture below. It's easy to miss if you don't know to look for it, but it's there. This particular image shows the aircraft on a heading of 282, and a track of 290.

It's a pretty tight fit, but hard to say whether you got the wrong part without pictures. All I can say is that when I've replaced that screen, the inner diameter portion of the screen always winds up slightly "flared" after pressing it around the structure of the selector.

There's a pervasive opinion that keeping the gear in the wells of an RG aircraft is a critical component of a safe ditching. But the only serious analysis I've ever found suggests it probably doesn't matter, see "Myth 5" at http://www.equipped.com/ditchingmyths.htm Note that this analysis doesn't involve the specific case of forgetting to raise the gear for a water landing in an amphib, which is a totally different subject, but sometimes trotted out when people insist you'll immediately flip upside down with the gear out. If this assertion doesn't pass your common sense test, think a moment about the geometries. Imagine you're ditching in your 35' wingspan Mooney (17.5' per side) with its 5.5 degree dihedral. The height of the wingtip over the water in a perfectly level touchdown on glass-smooth surface is only tan(5.5) * 17.5 = 1.7 feet. That's not much clearance. It's well within the range of normal beach waves, boat wakes, or blue-water swells. Throw in even a degree or two of bank past level at touchdown, and I'd say it's very likely you're going to catch a wingtip if you ditch gear up. So in practice, the gear up/down decision is the choice between sticking the gear legs in the drink first, vs. sticking a wingtip first. Neither of those is appealing. Both could easily result in rapid submerging. and they're probably in the same range of risk. Proponents of the "keep the gear up" strategy seem to assume you'll slide the belly smoothly into the water, perhaps after skipping a couple of times like a flat stone. But I think that's extremely unlikely in practice, and therefore a bad assumption to plan on. Anyway, not trying to convince people one way or the other about their strategy, just giving some information that doesn't seem to get into the debate very often.

Not really my place to speak for him, but since gsxrpilot's name was bandied around here briefly, I thought I should note that I talk to Paul on a regular basis. He still has his Mooney, still enjoys flying it (along with his taildragger), and doesn't have anything negative to say about Mooneyspace. He doesn't have anything positive to say about Mooneyspace either - he doesn't talk about it at all. But I know he didn't leave in a huff, has no bone to pick. While his specific reasons for not visiting here any more are his own, I'm pretty certain it has little to do with the nature of this community, and much to do with a healthy desire to get off the internet and enjoy real life. Those of you that think he got "run off" are reading far, far too much into things.

Well, you learn something new every day. I was about to post how you can't do that, but then I thought "Ragsf15e is pretty smart, he probably knows what he's talking about". Sure enough, with GTN navigators and per the AIM, you can legally use GPS guidance on a conventional VOR approach. See https://bruceair.wordpress.com/2018/09/06/use-of-gps-on-conventional-approaches-update/ I'm a little embarrassed that I'm 5 years late on this "news".

Yes, GPS LNAV approaches have fixed sensitivity from the FAF to the MAP. These approaches are "older", I guess (I'm old enough that every GPS approach seems "new" to me...); but they're still in use everywhere obstacles or other factors preclude having an LPV approach. The A-N/NDB/VOR transmitters around which non-precision approaches were originally developed are angular, so course width narrows as you get closer to them. However, the practical behavior of the CDI needle on these approaches depends on where the transmitter is relative to the airport. When the transmitter is on the airport, the non-precision approach narrows significantly from the FAF to the MAP, just like an ILS or LPV. However, in many (my guess is most) cases, the navaid on which a ground-based approach depends is not on the airport, but instead far enough away that there is no significant difference in needle sensitivity between the FAF and MAP. The best analog for that in a GPS implementation is fixed sensitivity, and I'm guessing that's why LNAV approaches work that way. Probably a lot of discussion about it during development, but I don't have any direct insight into how the decisions were made.

While I haven't read the study, I'm sure you're telling the truth. Be a little careful with the audience being studied, though. There are operational differences between "professional crews" and "average GA pilots", worth thinking about. I mention this because anecdotally, as a piston GA CFI, I'll tell you that my experience is exactly the opposite of the NASA study. Pilots I fly with who use electronic checklists are more prone to make checklist errors than those using paper. I don't know why this is, and I don't discourage electronic checklist usage, but it ain't a panacea. I think part of the difference doesn't really have much to do with electronic vs. paper, but rather that because electronic checklists are arguably easier to customize, they're more often to be customized by pilots who aren't actually skilled in the art of what constitutes a good checklist. That would be another major difference between my experience and the NASA study of professional crews.

The operational advantage is not to you, the individual pilot; but to the TERPS staff who design the approaches, other pilots already used to flying them, and the overall integration and track record of the system as a whole. There is a long history and body of work associated with high-precision approaches having angular rather than linear sensitivity (ILS technology was first tested in 1929). TERPS staff know how to design such approaches using standards that have achieved unparalleled operational efficiency and safety, including Cat III autoland in 0/0 conditions. There is no good reason to change all this just because GPS is "naturally" linear rather than angular. It would likely introduce confusion and new problems in exchange for no benefit. I'm not saying it's wrong to be miffed by this if you're new to the game and and a GPS "native". But as with getting ATC vectors as headings rather than track, and consuming weather information with teletype-era abbreviations... everyone already in the game knows how to use these things, and there is no particular operational advantage to changing them. In summary, why shouldn't a GPS-based "precision" approach have angular sensitivity just like an ILS? What would be the operational advantage of having it work differently?

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.