Vance Harral

Believe it or not, older Mooneys have factory installed "straw" in the ventilation system. No, that's not a joke. Not sure exactly what the material is, but it's a light tan/yellow. Air comes in through the overhead scoop and passes through this "filter" before entering the cabin. I think the idea is that if the vent is open when flying through clouds and/or rain, the moisture is strained out and runs down a drain tube and out the belly rather than entering the cabin. The M20J has a different ventilation system with a tail scoop, so not sure if it's designed the same way. But since - as you say - it doesn't seem possible for rodents to get in there, I think you may be looking at factory-installed "filtration material". I'm pretty sure this has been discussed at least once before on Mooneyspace, but I'm not having any luck coming up with it on a search.

At the risk of putting words in someone else's mouth... this seems to imply that if engine replacement cost is $50K, the seller should ask $50K less than a comparable model with a new engine, $25K less than a comparable model with a half-time engine, etc. In other words, it values the installed engine at exactly $0. I don't see it that way, as either a buyer or seller. A functional engine that's already installed on an aircraft and running normally has a significant nonzero value, regardless of how many hours are on it. It's fair to debate how much value, but it's not zero. Arguing it's zero says you'd pay the same price for the airplane if the engine wasn't actually installed, but rather just sitting derelict beside the (unflyable) airframe. In fact, you should pay more, because the seller has already done you the favor of removing it for overhaul! I'll be the first to admit things are worth what people are willing to pay for them. Maybe most buyers haven't thought through the argument above. Or they have and they're just trying for maximum negotiating leverage in hopes of a desperate seller. But if a buyer actually gets a seller to discount the price of a flyable airplane by the full cost of an engine replacement, I think they're getting an unusually good deal.

This is a thoughtful question, I appreciate you asking. We've done oil analysis every oil change for 14 years on our airplane, and I feel good about the fact we do, especially since it provides long-term trend data. In our case the cost is split three ways across a partnership, and feels lost in the noise of larger maintenance and operating expenses. But we're aware there are several classes of engine problems that will not show up in oil analysis, and we don't have any illusions about it. When we value the airplane for insurance purposes every year, we base the value on comps without regard to whether or not said comps advertise long-term oil analysis. There are so many other factors in the value of an airplane that dwarf it. Were I looking to buy another Mooney and encountered a seller like you who gave rational reasons for choosing not to do oil analysis, I don't think I'd "ding" you on value. For me, it's more about attitude than execution. There's a big difference between a seller who says, "Our engine maintenance and health processes don't include oil analysis because we were unable to justify the time and value, we choose to do X, Y, and Z instead"; and one who says "That there oil analysis is just a scam! It don't mean s**t!"

I'm not sure I understand the question. This seems like asking if you need to worry about wind shear, or wake turbulence, or bird strikes, or other possible-but-low-probability events. If you're asking if it ever hails in June here, the answer is "Yes, occasionally."

Statistically? It's nice almost every morning, and bumpy with CU buildups and T-storms in the afternoon. Winds above 12K are nearly always out of the west. None of that statistical information is meaningful or helpful with respect to a particular day or week, of course.

While it's nit-picky trivia, it really is true that headwinds are (slightly) more common than tailwinds - if you define a "head" wind as something that reduces your ground speed. The reason is that a direct cross-wind doesn't have a neutral ground speed effect, it still slows you down a hair due to wind correction angle. At typical Mooney speeds and winds aloft, the neutral point is around 5 degrees quartering. In other words, there are 190 degrees of winds that hurt you and only 170 degrees of winds that help.

We have a '76F model too, presumably wired the same way as yours. I have the electrical schematics for it, PM me if you're interested in a copy. Assuming our airplanes are wired the same way, the switch you found in the wheel well is the "squat switch" that prevents the gear from being raised when there is weight on the wheels. It's normal for there to be a small gap between the switch and the plate when the airplane is on the ground - that's how it works. When you take off and the gear doughnuts expand, the plate moves to close the switch. The switch is actually a double-pole switch which routes power to one of two different sources when the gear selector is in the up position. If the squat switch is "closed", power is routed to the gear motor to raise the landing gear. If it's "open", power is routed to the gear warning horn instead. This is something I think a lot of people don't know - that there are actually two logical events that cause the gear horn to sound. Reducing throttle below the switch point with the landing gear up is only one of them. The other is attempting to raise the landing gear with weight on the wheels. Anyway, the squat switch has absolutely nothing to do with the green "Gear Down" and red "Gear Unsafe" lights on your panel. Those lights are controlled only by the limit switches in the belly. Those limit switches are also DPDT switches, meaning they have two independent switch circuits in a single housing, actuated by a single "button". Since you're able to get the "Gear Down" light to illuminate with the push-to-test switch, the problem has to be the down-limit switch in the belly. The external switch "button" and the internal half of the switch which controls the gear motor itself must be working - otherwise the gear motor would not have stopped running when you selected gear down, and the gear motor breaker would have tripped. So it's highly likely the half of the switch that controls the gear down light is the problem: either the internal guts of the switch have failed, or (hopefully) the wire connections to it have simply come loose. As owner/operator, you're absolutely allowed to remove the belly panel that allows you to look at the limit switches. If you find one of the wire terminal connections associated with that switch to be loose or disconnected, you can try wiggling it against the terminal it's supposed to be connected to, and I'd bet that will cause your green "Gear Down" light to illuminate. What you do beyond that is up to you - let your conscience be your guide. I think we all know the letter of the law. From an actual safety perspective, I draw a distinction between, say, an electrical engineer who has the schematics for the aircraft, a voltmeter to test the switch, and the experience to use both; vs. someone who just grabs a bottle of contact cleaner and uses the "spray and pray" approach.

The first time we ever changed the oil on our engine, we found a flake or two like that in the pleats. That was 14 years and about 1000 hours ago. In the interim, we've seen a flake or two like that every once in a while. Recent changes have been clean. It is indeed a good idea to pull the pickup screen, especially if you don't know when it was last done. Don't be surprised if it's full of carbon flakes. Yes, it's a bit of a pain. Long-nose pliers and dikes make a big difference in the amount of cussing necessary to get the job done.

Yeah, but the Dynon page for the D-2 says, "Sorry, the requested product is not available": http://www.dynonavionics.com/pocket-panel.php The Aircraft Spruce link says "Page not found", Amazon says "Currently unavailable" and so on. Can't find one for sale anywhere but used. Regardless of whether it's been "officially" discontinued, it appears discontinued for all practical purposes.

HUDs are cool, but some of the GA implementations are real head-scratchers to me. It's as if in pursuit of the HUD concept, developers forget you actually still need to look out the window to see "real" reality. Look at this thing I saw pop up on AvWeb today: https://epicoptix.com/blog/2017/07/video-head-up-display-for-light-ga-epic-optix-hud/ It's a gargantuan monstrosity. In the video on that page, the guy flying the demo not only has the HUD unit, but also two GoPros, a Garmin portable, some sort of antenna, and some other gizmo, all on the glareshield or windshield. I'm surprised he could taxi to the runway without hitting anything...

An LLC can be helpful when there are - or may be in the future - multiple owners/operators of the aircraft. Our aircraft is owned in an LLC for this reason. It's a Colorado LLC because that's where all the parties live. It was formed with 3 partners originally. Over the years a few individuals have sold out of/bought into the partnership. This was done by selling shares in the LLC, and hence did not require changing the aircraft registration, or filing any state or federal paperwork at the time of sale. The LLC also provides "some" (but not absolute) liability protection for one partner, if a different partner were to have an accident with liability exceeding the amount of the insurance policy we maintain. Note that the LLC does nothing in the way of liability protection for the partner actually operating the aircraft. In exchange for these benefits, we get the burden of maintaining profit/loss records and capital accounts in the LLC, filing a separate tax return for the LLC every year, distributing K-1 forms to the partners, and following the required rules for operating a Colorado LLC. These things are not particularly onerous or expensive in Colorado, but it's still a nonzero effort and expense - enough so that we pay an accountant for help. It's particularly important to follow the requirement for an annual meeting, and document it took place. If you don't follow this rule (and any other applicable rules), it's trivially easy to "pierce" the LLC should push come to shove. I've never understood the interest in forming an LLC to own an airplane when one is and expects to always be the sole operator. I suspect most people who do this think it provides some form of tax advantage and/or liability protection that it simply does not. I'm not well-educated about states outside Colorado, though. I guess I'd ask what benefit(s) you're interested in by forming an LLC, and what you've been advised about those benefits by actual, practicing tax and law professionals.

A couple of folks above have suggested the brown staining around the fuel tank access panel is sealant "oozing out" from a prior R&R job. Maybe. But it's more likely to be fuel seeping through the access panel from degrading sealant. The blue dye in 100LL fuel turns reddish-brown over time and leaves these sorts of stains. Significant leaks show blue staining, but very small leaks (or leaks that have been recently cleaned of blue staining) show only reddish-brown marks at seams. I know this from observing our own airplane, which has had access panel seeps over the years. For another example, see the first half of the attached video, which shows significant Mooney fuel tank weeping. The reddish-brown stains in the video aren't rust, they're what's left when the blue dye dries and desiccates.

Hrmph, sorry about that. I just assumed this was the same on all airframes that had the Brittain aileron servos, but clearly not. I'll try to remember to take a photo of mine next time I'm out at the hangar.

Glad they helped, good luck with your project! For what it's worth, suggest you pay heed to jetdriven's troubles with binding after reassembly, which is part of the reason we sent our unit to LASAR for overhaul. We spoke directly with Dan Reisland about this, and he said reassembly of the "guts" inside the block (bearings and shims) is critical, and if not done just right can lead to exactly the sort of binding jetdriven talks about. My guess is it mostly has to do with selecting the right size shim(s) to minimize play without binding up. The right size depends on detailed tolerances of the block and the bearings, and installing different bearings affect that, even if the new bearings are the same part number. So something of an art, based on experience. That's my impression, anyway. If you're just going to clean and reassemble your existing parts, I'd guess odds are they will go back together fine. If you're contemplating new bearings, or your shims are worn, or you just want a slightly bigger shim to tighten up play, you may want to let the pros do it. At the risk of sounding like a shill for LASAR, Dan was extremely helpful to us with this, as well as our landing gear work, at our recent annual. I'm sure the LASAR guys would be the first to tell you these are just mechanical parts and they're not some sort of mystical gurus. But they do this sort of thing every day, and experience counts.

The problems that can occur when the system is neglected - which it often is for long periods of time due to the pain of disassembling it - are as follows: Old, dried up grease in the bearings - this wasn't as bad as I thought it might be in our airplane. It is essentially sealed, after all. Wear in the bearings from normal, long-term use - this was our biggest problem. Shims worn, or not the right size in the first place. You can see in the photos above we had only a single shim, and was allowing a fair amount of play. Wear in the "screw" itself. In our case, there was almost no wear, and the folks at LASAR say it isn't unusual for it to actually be in quite good shape when inspected. When we got things disassembled to the point of the last photo above, we realized the bearings were in fairly bad shape. We hadn't yet ordered replacements, and when we realized it would require a puller to get them off the shaft, we chickened out and just overnighted the whole thing to LASAR. Dan fixed us up and had the freshly overhauled unit back in our hands in less than a week.

If you remove the bolts and nuts that hold the "block" together, you can slide it off the bearings that allow the screw to turn, as well as remove the shim(s) that take up the play in the system: Here's the shim: Here are the bearings after sliding the block off. Note that the bearings are press-fit onto the shaft. You need a puller of some sort to remove them: This is as far as we got before we chickened out:

Not PeytonM, but we overhauled our jackscrew assembly (by which I mean we R&R'd it, and had LASAR actually do the overhaul) just about a month ago. Here's what it looks like when first removed from the airplane. The big block in the middle contains the "nut" and the bearings. That's where you're going to find the old, dried up grease, as well as the (probably worn) shims. The shaft on the right attaches to the trim control rods that go down into the belly. The "screw" part on the left attaches to the tail, and is what's underneath this boot you can see when you remove the empennage fairing: Note the hole at the far lower right of the above photo. There are four of these, and that's how you get access to the bolts that go through the square block, and hold the jackscrew assembly in place.

Thanks for the info on traffic alerts, Maurader. Based on your pointer and a little more research, looks like both the GTX-345 and the NGT-9000 call out azimuth, high/low, and distance. The connection to a WAAS GPS isn't an issue for us because we already have a GTN-650. So the flip-side of the argument is that with the NGT-9000, we're arguably paying for a WAAS GPS receiver we don't need. We don't have any installation quotes yet, so time will tell on walk-away price. But I can't imagine the installation costs on our particular airplane would vary much between the two boxes for just their respective basic feature sets. That just leaves the price delta on the hardware itself. The partnership is hoping to get out of the shop for $7500 or less. Maybe way less, as various, much-less-capable options are also still on the table for us. But we wont' really know until we start requesting quotes. The only thing we know for sure is TAS is off the table - we'd rather spend those dollars elsewhere. That makes the comparison between the GTX-345 and the NGT-9000 a close heat.

Thanks Maurader, great explanation. Question for you: when the NGT-9000 generates an audio warning, does the voice tell you where to look? Something like "Traffic, 2 o'clock low!". Or does it just say "Traffic!"? And is it any different with the Garmin products?

I'm still curious where the TargetTrend algorithms are implemented. If they're in the 345 itself, then any display device - including Foreflight, FltPlan Go, etc - could theoretically display those trend vectors. If they're part of the software in the display device instead (GTN-650 or Garmin Pilot or whatever), it's unlikely Garmin will ever give Foreflight or another EFB vendor the algorithm. Also, if they're in the display device, then two different devices could potentially be running two different versions of the algorithms. I can see this coming up with traffic display on a GTN vs. Garmin Pilot. Garmin does a decent job rolling out GTN firmware updates, but it's a little annoying that we have to make a trip to our avionics shop and drop them a check for $100 every time we want the latest GTN firmware. I'm aware some avionics dealers do this for free as a courtesy, but the shop that installed our 650 isn't one of them. Consequently, we only upgrade the firmware every year or two, instead of every time an update is available.

Well, for one thing, you apparently can't buy one any more. That page you linked to says "Sorry, the requested product is not available", and I can't find one for sale anywhere but Ebay. I think the relaxing of TSO rules, combined with the relatively small price difference between portable/backup AHRS units that display on an EFB and things like the Dynon D10 and Garmin G5, have essentially eliminated the market for things like the Dynon D2.

Can someone expand on TargetTrend? Garmin isn't the only vendor which provides a traffic display that paints a track vector for threats, so I'd like to better understand the details. For example, here's a screen grab from an AOPA article on the Lynx NGT-9000. There is clearly a vector line for the yellow threat target, and the two non-threat targets have altitude trend arrows that indicate those aircraft are climbing: My understanding is ADS-B/ADS-R message content includes latitude, longitude, altitude, heading, and horizontal and vertical velocity. While the message itself doesn't contain any "trend" information, it's pretty trivial to compute a future position for a target, assuming it doesn't change its current flight path. It seems like I've seen a lot of traffic displays with this sort of trend data. This gets more complicated if the target is changing it's flight path. I can imagine a "smart" box comparing several data points for a particular target, realizing it's turning, and heuristically painting a curved vector for the target on the display. Does TargetTrend (or similar products from other vendors) do this?

This would certainly be an important piece of information. @Cruiser, can you provide a link to this recommendation, or is it just something you heard in passing?

Right. And at around 1 AMU for the 660 and a panel dock, that's considerably less expensive than a G5 or similar. Still a lot more expensive than velcro'ing an old cellphone to a blank spot on the panel, though, which is what got this thread started. Decisions, decisions...

Well, I'm not sure I'd call the AHRS in the GTX-345 "portable". It's hard-mounted in a unit that's as firmly fixed to the airframe as any certified attitude sensor. If you have an Aera in a panel dock, you can hardwire it to the GTX-345 and get an attitude indicator whose connectivity robustness is equal - or at least very close - to what you'd get with an ESI-500 or G5. The internal sensors and firmware of the AHRS in the GTX-345 may not be as good as an ESI-500 or G5. I don't know about accuracy, update rate, etc., and not sure how I'd research that other than asking for PIREPs. It's also true that if you display the attitude information via Bluetooth link on an EFB instead of via hardwire connection to an Aera (and we don't even have an Aera today), that's a more complex system with more failure modes. But I think the GTX-345 AHRS is an interesting animal in the overall landscape. As a backup source of attitude information, it's robustness is probably somewhere between a genuinely portable solution (e.g. Stratus 2 or iLevil), and an ESI-500, G5, or even a simple Mid-Continent Lifesaver. So not a gold-plated solution, but to me it has nonzero value that makes the NGT-9000 look that much more expensive for its lack of AHRS. And before the cheapskate debate spools up - this isn't about being a certified CB. If our partnership had an extra AMU (or ten, or a hundred) to spend on "safety", there are better ways to spend it than on increasingly robust backup attitude indicators. Primarily training, to be honest. The odds of pilots doing something stupid in VMC due to lack of proficiency are tremendously greater than augering in because their backup AI let them down in the soup. We're not arrogant enough to think we're special in that regard. Again, I appreciate all the thoughts and conversation. Still trying to understand the pros and cons of the many ADS-B solutions available to us. Haven't entirely ruled out a (theoretically) less-expense 978 MHz UAT solution, either. Seems like there's a new solution every few months or so. But we're creeping up on the 2020 deadline, and we want to be equipped by then, even if there's a long wait at the avionics shops.