Vance Harral

You understand the manual correctly, assuming it works like our B5. The CAPTURE setting sets up a 45 degree intercept to a radial you're not yet on. When the VOR or localizer needle comes alive, the unit will turn on to the radial as the needle centers up. Once that's complete, you switch from CAPTURE to TRACK (for enroute navigation) or APP (for an approach). The difference between CAPTURE and APP is different multipliers in the controller circuit. "Aggressiveness", if you will. I expect the APP setting on our B5 and the LOC setting on your unit behave the same way. Regarding altitude hold, what moves the elevator is a pair of vacuum servos attached to the elevator push rod. The "pitch trim" indicator that goes in the cutout indicates how much vacuum is being pulled in one direction or the other. The idea is that if the indicator is consistently on one side or the other of center, you can roll in/out a little elevator trim to help the autopilot. Attached is a picture of our B5, with the pitch trim indicator.

I don't have a photo handy, but for what it's worth, our gear have roughly zero clearance there (can see a bit of the paint rubbed off). I've wondered about this too.

Just to follow up... when it was time to reinstall the fuel selector, the A&P offered to do it, and I said "be my guest". He didn't drain the tanks, but opted for the quick-draw routine instead. I made sure the airframe was grounded and stood by with a fire extinguisher. I respect the opinion of those who think this is excessive risk, each owner and mechanic must make their own decision. For others reading the thread... the thing that makes this a bear in a Mooney is that the fuel selector is in tight quarters. The nearby structures, the plugs being installed/removed from the lines, and the fuel selector itself, all tend to get in the way of each other.

OK, I'll play, but keep in mind I'm just an amateur, not an A&P. 1. Too blurry to be sure. The panel it's near is a fuel tank access panel, which makes me suspect it's a fuel stain. But it would be more common to see that on a screw, or the seam of the panel. That stain is just in the middle of nowhere, so a bit odd. 2. Looks like rust, at least in some places. Light surface corrosion on gear trusses is not a show stopper. When I point out things like this to my long-trusted mechanic, he tends to say things like, "Yeah, that might rust through in another 50 years or so...." 3. Service manual calls for spraying lubricant on all hinges every 100 hours (typically every annual). As the lubricant dries, discolors, and gathers dirt over the years, it tends to stain the hinges and nearby sheet metal a bit. My airplane has the same discoloration on and around hinges. Not a show stopper. 4. I'm guessing that's the connecting rod back on the elevator or rudder, little hard to tell from the photo. If so, there are no grease fittings back there, so doubt it's grease. Might be dried lubricant, might be rust. If the latter, again, light surface corrosion isn't a show stopper. 5. Those look like blind rivets, not screws. They appear to be "working" a little, i.e. loosening up. Working rivets can be drilled out and replaced, but it of course cosmetically messes up the paint. My mechanic doesn't get worked up about the occasional smoking rivet here and there, but different people have different opinions. 6. Worst case scenario would be water and rust behind the panel, caused by lack of attention to Mooney Service Bulletin M20-208B. Or it could just be a stain from a backseat passenger spilling food or a drink. Only way to tell is to perform an M20-208B inspection, but you should be doing that as part of the pre-buy anyway, regardless of whether you see stains or not. 7. Again, looks like blind rivets "working" a little. Not really familiar with speed brakes or how much of a concern this is. 8. Just looks like paint nicks to me. 9. Might be some rust under the bolt in the lower left of the photo. But most of what you're seeing there appears to me to be dried lubricant and dirt, as discussed above. 10. Looks like touch-up paint to me. The trailing edges of control surfaces tend to get paint chips. Not sure why, maybe vibration, lack of bonding at the corner, or both. Sometimes people dab on a little touch-up paint, which usually looks awful. 11. Looks normal to me. Lap joints around compound curves fastened with rivets can buckle a little, even when factory new. Overall, while I appreciate your meticulousness, I'm a little concerned you're missing the forest for the trees. Little specks of rust on replaceable components you can see with a casual glance, or the occasional smoking rivet, are not what cause nightmare scenarios. The places you want to be looking for nightmare corrosion are on the main wing spar and aft stub spar, the steel roll cage structure under the interior panels, and inside the engine.

Yeah, I'm really not sure what's going on there or how the airplane was jacked up in that photo. It's from before we bought the airplane, part of a collection of photos the prior owner gave us. Just happened to be a good shot of the inspection panels.

The paint nicks and dirt you're seeing on the gear trusses and in the wheel wells are very common. Doesn't necessarily mean they're "OK", but not at all uncommon. The trusses and gear wells in our airplane looked much, much worse the day we bought it. 14 years later, neither the gear nor the wing spars have fallen off. The black streaks running out of those close-out panel rivets look "wet" to me. If so, that may indicate the inside of the wing has been fogged with an anti-corrosion treatment, which is a good thing. Don't confuse "inspection panels" which are designed to be removed for service and inspection with "closeout panels" which are only needed during manufacturing. The latter are typically riveted closed. For the person asking about external inspection panels with round-head screws, our airplane has those. Picture attached below.

Couple of comments to add. First, I think it's important to point out that what's ultimately certified in the certification process is an "installation", not just a "device". I don't know what manufacturer's GPS receiver is installed in a iPad, but let's assume it's the same one in a GTN650 (doubt it, given that that the integrated circuit in the iPad is a combination GPS receiver and 4G integrated circuit, but that's not really germane...) Even if we set aside the difference in software that talks to the GPS receiver, the receiver's behavior and performance depends on the GPS antenna being used and the connection to it, among other things. Panel-mount GPS hardware is connected to an external GPS antenna mounted on the roof of the airplane for best reception, and that entire installation is addressed by the certification process. The iPad's antenna is inside the cabin near a bunch of other RF devices, potentially changing every time you move the iPad. That doesn't mean the iPad doesn't work well, but there's a reason why different pilots in different airplanes have different experiences with reception on portable devices. As another example, I fly with a Stratux portable ADS-B in setup. It works great, but only if I hold the antennas up to cabin window, and move them around depending on where I am. That's not something any reasonable person would "certify". On the other hand, it's important to understand the certification process isn't the gold standard most certification advocates imagine it to be. I have a relative in the certified avionics software business, and when he tells me how the boxes are verified vs. the way I do things in the microprocessor design world, it makes me uneasy. Here's just one of several cringe-worthy stories I've heard from him: [my relative]: I opened a bug because if you press button A followed by button G followed by button C, the whole box locks up and must be power cycled. [responder]: Bug closed, that's an invalid key sequence. [my relative]: Bug re-opened. It's never OK for the box to lock up, regardless of whether the key sequence is "valid". [responder]: Bug closed, no pilot would ever do that. [my relative]: Bug re-opened. You're not a pilot, are you? Ever flown in turbulence, accidentally hit the wrong key? [responder]: Bug closed, that's just not part of our certified test sequence. [my relative]: Sigh. I give up. [DER]: I see you've closed all open bugs, looks good for certification sign-off! Even from a single manufacturer specifically in the aviation business, there are holes in both certified and uncertified flows. Shortly after acquiring a Garmin GPSMAP396, I found a bug in the way the HSI behaves when turning away from the FAF on an approach, as one might do entering a hold or procedure turn. I reported the bug to Garmin and they confirmed the bad behavior. But it was never fixed, and their final response was essentially, "Yeah, it doesn't work the way we meant it to, but you're not really supposed to be using it for reference on approaches even though the software gives FAF-to-MAP guidance". Later, we put a GTN 650 in the airplane, and subsequently received notice of a bug wherin if you configure it with a user-defined field that is a shortcut to a checklist, it can "brick" the unit, requiring a visit to the avionics shop to fix it (see Garmin Service advisory SA1503). You'd think the certification process would have caught this, but nope. No guarantees either way.

I'm not advocating pulling a cylinder. That would allow you to look at the cam and crank, but is major surgery and yes, the seller would probably object. "Borescoping the engine" typically just means putting the scope in a spark plug hole and looking at the top half of the cylinder, above the piston. With a good scope (even a $40 endoscope off amazon.com), you can see the cylinder walls and the valves. All that said, if the engine was overhauled 3 years ago and has been flown 625 hours since, skipping borescoping altogether is probably not an unreasonable risk. That's good, healthy exercise for the engine, and I agree it's unlikely (though not impossible) to have internal corrosion issues. You could still borescope the cylinders to look for evidence of premature cylinder wall wear and/or exhaust valve problems, though. The procedure is not really invasive or time-consuming. The risk to the seller is just the possibility of a ham-fisted mechanic accidentally dropping a poorly-attached borescope mirror down in the cylinder. That isn't catastrophic, since there are some tricks to retrieve such things, but it could happen. Overall, your call.

I don't know the airplane, but nothing on the list you attached looks like a show-stopper to me. Agree with Alex you should further investigate the gear issues, but not sure I'd characterize them as a "big thing". Shims, bearings, and rod ends are straightforward. I'd need to know exactly how much the preload is out of spec before expressing an opinion on that - the factory-prescribed method of measuring preload tension via torque wrench and breaker-arm tools is prone to a lot of measurement variation. If you're going to repair the gear spring attach bracket, I'd consider installing new springs on both sides, which may bring the preload measurements back into spec anyway. I'd also take a close look at the nose gear. The play the shop is proposing to fix with shims and oversize through bolts may in fact require a whole new steering horn (that was the case with our airplane when we started to get nosewheel shimmy). The biggest question I'd have is, what is the complete list of stuff actually inspected on the pre-buy? The attached report shows a bunch of easily fixable items, but doesn't say things like, "Inspected spars and spar caps for corrosion, looks good"; or "removed interior panels to inspect roll cage for corrosion, no issues found"; or "no evidence of decaying tank sealant found in gascolator screen"; or "borescoped all four cylinders, valves and cylinder walls look good". A pre-buy which finds and offers to correct a bunch of minor issues is essentially worthless if the inspection overlooked all the major, expensive stuff. Sure is a good-looking airplane with a nice panel. If the bones are good, seems like a fair deal.

Thanks for arranging the group buy, Dan, ordered mine today. Your story inspired me to trade in my "better than nothing" home unit for something really designed to do the job.

Several years ago, we replaced the rubber duct that runs between the air intake box and the fuel servo in our M20F. This part is the subject of multiple threads here on MS, involving cost, quality, availability, and the wisdom of repair vs. replacement. We replaced ours because the old one was torn, had been sloppily repaired with RTV, and was coming apart again. Our replacement duct is working fine, but I'm starting this thread to solicit input on what to do with the old one. It's been sitting in a box in the hangar, for no other reason than it seemed like a bad idea at the time to just throw it away. Climate around here is such that it hasn't deteriorated any further that I can tell. Theoretically it could be repaired and held as a backup, especially since there's no urgency for a "quick fix", and a replacement might not be available in the future. But if we really cared about having a hot backup, we could order a new one from LASAR or Mooney or whatever vendor has them in stock today. What say the denizens of MooneySpace: repair or toss? If the former, what's the best, no-apologies repair technique, and is it even worth the trouble?

There are certainly right and wrong ways to use them, including buying ones rated for the heat/light they're exposed to, and using appropriate tension and cutting methods. To be clear, I'm not "anti" zip-tie, just advising reasonable caution, especially in areas you don't see frequently. This is of course true for any method of securing wires, not just zip-ties. For anyone truly interested, AC43-13 Chapter 11 has specific guidance on securing aircraft wiring, see in particular 11-96 (a), (b) and (o); and 11-146. The big no-no is securing wiring to structure without some sort of stand-off. Adel clamps provide that standoff inherently by design, and hence are arguably the gold standard for securing wiring. Some people interpret that guidance as an FAA "rule" prohibiting zip ties in various applications, but I'm not one of them.

Pulling a zip tie tight enough to ensure it never moves - especially in a vibration-prone environment - is likely to damage the thing you're securing with the zip tie in the first place. Certainly true of electrical wiring, sometimes true of cables and other structures.

The other reason to be careful with zip ties is the serrations that the lock piece clicks into can act as a saw over time, cutting wiring insulation and even metal. I use them in places I can see on a normal preflight or oil change, especially if I can put some electrical tape around the place they're installed. But I'm less prone to use them in places that only get looked at during annual. If you really prefer zip ties, good cutters and care in using them are worth the extra time. Another good trick is to put some heat shrink tubing over the portion of the tie that will be tight against the wire/metal/whatever when it's tight. That buys a little bit of protection against the sawing action. But it requires a good estimate of what the used length will be once everything is pulled tight.

At the risk of patting myself on the back a little... just downloaded all the photos from the annual to my phone, which allows for a better before/after comparison. As you can see, the landing gear cleanup made a dramatic difference!

Just finished downloading pictures from my phone to my computer and wanted to follow up on this. I did find some pictures taken from the endoscope camera that were 1024x768. While that is not 2 megapixels, it is higher than 640x480, and is in fact the highest resolution selectable waith the cheapie app the directions instruct you to download. I now remember that at 1024x768 resolution, I wasn't able to see an entire valve at once (see attached photos below). Switching to 640x480 effectively "zoomed out" such that the image showed the entire valve. I know, I know... this doesn't make any sense. The resolution of an image and the optical (or digital) zoom are independent variables. But again, I think the cheapie app software is to blame. My guess is it processes the raw data from the camera differently depending on the resolution you choose. I would bet it's trying to be "smart" in a way that's exactly the opposite of smart. In summary, I think what I bought is a pretty decent little endoscope camera, that presently suffers from being used with poor software.

Thanks for the complement, but they look better in the photos than in real life. I didn't actually strip them down to bare metal. I just did a "scuff and shoot", and you can see the old paint texture underneath. I was running low on paint in the rattle cans, and it seemed like a reasonable compromise since almost no one ever sees them up close and personal. Different models may attach the shields a different way, but I didn't have much trouble with mine. They're held on with 10-32 machine screws, through Adel clamps, and into self-locking nuts. The trick is to use safety wire to pull the Adel clamps together, then get the bolt/nut started, then cut and pull out the safety wire before tightening everything up.

The machine in the shop I'm using is set up with glass beads It worked "OK" for removing the paint and underlying zinc chromate primer from the trusses, but took a lot of time and patience. I did the first one "dry". On the second one, I took the mechanic's advice to apply a chemical paint stripper first. That took most of the paint off, leaving only the chromate, which still required a lot of bead blast work. Actual sand is better for paint removal, but the more abrasive media you use, the more careful you have to be not to pit the target. For a junior birdman, non-mechanic like myself, glass beads were probably the best choice. I had and still have mixed emotions about removing the chromate primer along with the paint. I had a number of spots where the primer was worn away and the exposed steel was exhibiting some surface corrosion, so full cleanup seemed best. But the self-etching primer I used for the re-paint probably isn't as good as the original chromate. ZC is also pretty nasty stuff. I've sanded or media blasted parts with it on a couple of occasions including this one, but it always makes me a bit nervous from a health perspective. I actually used rattle cans made up by a local automotive paint shop. 3 light coats of self-etching primer, followed by 3 fairly heavy coats of color. I set the parts on a ladder underneath the shop's full-hangar heaters over the weekend, as a poor-man's baking oven. It remains to be seen how well the job will hold up to use. Our airplane isn't a showpiece, and I wasn't really trying to achieve a high-end result. Just something to tide us over a few years until a theoretical future paint job. The gold standard would probably be powder coat, but that would have required more time, money and logistical management than I was willing to spend I did shoot some beads at the inside of the tube, and also scrubbed it out with a wire brush, but I didn't try to make it pristine like the outside. It probably still has some chromate on the inside, which I think is a good thing. I'm relying on that and a heavy dose of LPS-3 for corrosion protection. Now that I understand how to access the top of the tube, I'll probably re-shoot it with LPS once or twice a year. I agree it's a potential trouble spot that could collect water, but the operating environment mitigates the concern in our case. It's a pretty dry climate here, the airplane is hangared, and we rarely fly actual IMC (clouds around here tend to be full of ice in the winter and thunderstorms in the summer).

For what it's worth, the attachments for the camera I bought screw on with fine-thread screws. It requires 8+turns to get them all the way seated. I think they're extremely unlikely to fall off inside the cylinder. I've seen borescopes where the mirror attachment just slides on with spring clips, and agree that seems dubious. At some point I might try finding a small, high quality tiny *glass* mirror and epoxying it onto the plastic mirror attachment for my scope. For now, though, the 180 degree bend works well for looking at the valves. Not sure how many times I'll be able to switch it back and forth to look at the piston and cylinder walls before the wires break from flexing, though.

I haven't tried to determine why the saved images from the camera are only 640x480. I suspect it's a software issue with the phone app rather than the camera itself. The reason is I'm not sure anyone is even making a 640x480 (0.3MP) CMOS sensor any more. My bet is the sensor really is a 2MP sensor, but the cheesy-poof app the instructions have you install on your phone is downcoding the saved images. One supporting piece of evidence for this is the real-time images displayed on the phone while I was looking certainly seemed to be much better than 640x480. I was using an iPhone 6 with a retina display. If the image being broadcast to the phone had really only been 640x480, it would have looked awful. But it looked just fine at the time. The app has a settings button that allows you to change the displayed resolution (maxes out at 1080x800), and I could tell a difference between the settings on the live display. I guess the silly, ironic thing is I could get higher-res images by using another phone to take a picture of the first phone while it was displaying the live image. The app can take both still pictures and video, but it will only take video if you change the resolution to 640x480. This makes sense, as it's a bandwidth issue, and the hardware in the encoder is probably low-end. I wouldn't be surprised to learn the app is just using the same routines for video and saved pictures, such that the saved pictures wind up being only 640x480 even though higher resolution is available in the raw data. If so, you could get better saved images with a different app. I probably won't make any attempt to contact "support". Based on the instructions and the app, it's clear the whole thing was built somewhere on the other side of the globe, and I have little hope there is any meaningful support. I don't mean to be snarky about that. I try to appreciate the fact that at $40, it's essentially disposable. If I was going to invest energy in this, I'd probably look for other apps that can talk to the camera (your idea of trying to use a laptop is a good one, but I'm not sure where I'd find appropriate software). Based on the number of very similar devices for sale at Amazon, it seems clear there are several distributors re-branding the same hardware. One of them might have better software, or perhaps better software will become available in the future.

I think it's more likely to just be a symmetric pattern of deposits, with slightly less "goo" at the center. All I know is the exhaust valve in all 4 cylinders looked the same, so I consider it normal at 1850 hours SMOH. Mainly I was looking for green coloring, asymmetry, or evidence of damage at the edges. I saw none of that, so I have no serious concerns about valve health. I am not an engine expert, but one of the mechanics at my shop spent a decade working at an overhaul shop and said everything looked fine. He guided me not to over-analyze things. He said you can drive yourself crazy looking at every tiny scratch or anomaly inside a piston, but that the point of a borescope check is to look for grossly obvious signs of impending doom.

On review, I'm embarrassed to say I mis-read the parts manual. Flymac is correct - the bolt I was looking for is the AN9-24A he references from the parts manual. Apparently not available from Aircraft Spruce (at least not via online search, maybe they do have stock if you call). But available from Skygeek, albeit at over $30 apiece. The 914007-005 part number is the bushing associated with that large bolt. That's a Mooney part number, not sure it cross-references to anything standard. But when/if I replace that bolt, I intend to replace the bushing, too. As I mentioned, ours has some score marks. The special bolt with the oval head that goes through the collar is in the second picture above if you look closely. It's at upper right, immediately below the shock disks themselves. I'm not sure how much trouble it would be to replace those collars, Flymac. They're definitely Mooney-specific parts, not sure if the factory has them in stock or what they charge. I debated painting them, and did so only because I already had everything set up for paint. The point wasn't to make them look pretty, but just for corrosion protection. The collars appear to be a non-stainless variety of steel, and showed some light surface corrosion. But a liberal dose of LPS-3 or similar on assembly, and periodic re-spray of same at annuals is probably just as good as paint in that department. If you do paint yours, either mask the inside of the collar before painting or sand it smooth/thin after. The fit of the collar over the top of the shock disk tower is tight, and any excess paint will make it harder to slide the collar in place.

I, too, bought a cheapie $40 Amazon.com special and used it today to look at the valves in my engine. The model I bought is slightly different than the one tigers2007 linked to, but I suspect it's the same camera and guts. The link to mine is https://www.amazon.com/Endoscope-Depstech-Inspection-Megapixels-Smartphone/dp/B01MYTHWK4/ref=sr_1_4?s=photo&ie=UTF8&qid=1486614401&sr=1-4&keywords=endoscope I also seem to have the problem where saved pics are always 640x480, even when I select the highest resolution (2 megapixels would be 1600x1200 in 4:3 aspect ratio). It's not immediately obvious to me if the camera is only a 0.3MP camera or if this is a software problem in the free app which the instructions tell you install on your phone. That said, I was still able to get some nice, clear images of my valves, see below. Note that while the camera comes with a 90 degree mirror attachment, it didn't work as well as I hoped. The mirror had minor defects out of the box (I suspect it's made of plastic, not glass), and I found the camera was focusing on the mirror surface itself, rather than the reflected image. But the camera and cable were small and flexible enough that I was able to bend the camera 180 degrees around and safety wire it to the cable, with the resultant apparatus still being skinny enough to fit in a spark plug hole. After playing with various cable bends, I was eventually able to get some nice images. The mechanics at my shop agreed the images are as good or better than they can see with the Snap-on borescope they paid $800 for several years ago.

Here are some pictures, for the curious. They attached in reverse order for whatever reason. Bottom photo is lower truss taken down to bare metal. Next above is post-paint, with all new fasteners (except for large shock disk tower bolt). Next above is everything ready for re-install. Top photo is post-installation.

Yes, good advice to order new bolts/nuts/bushings for the next opportunity. While I think my paint job on the bolt and nut will hold up OK in the short term, the act of installing the bolt takes some of the paint off, of course. Also, the bushings were "usable', but have some scoring and should be replaced within the next year or so, too. I think some of the bearing wear was a result of not really getting grease all the way through the bearing at past annuals. It had become pretty difficult to push grease from the zerk out both sides of the bearing, seemed like it was always just squirting back out the zerk, or out one side of the bearing at best. Easier now after disassembling and cleaning everything. Paul, I took a good look at our shock link towers based on your comment about replacing them in your own thread. They had some light surface corrosion on the exterior (i.e. the parts you can see when everything is assembled), as well as some wear on the tube that holds the disks. But nothing significant in terms of wall thickness. I took the exterior portions down to metal with a bead blaster, then primed and painted them. The interior tube still had most of its original chromate coating intact, so I just cleaned it lightly with a scotch brite pad and solvent, then sprayed a liberal dose of LPS-3 on when installing the new disks. I'm pleased with the way everything is going back together, and with getting a serious look at the state of the trusses and hardware. The old paint and dirt was so gross that we worried every year about the possibility of a major crack or corrosion hiding in the paint chips and grime. Cosmetically it's going to look much nicer, too. I just wish it didn't require so much time and effort to really do things the right way. I've been working on this in the shop about 8 hours a day for the last 4 weekdays, including getting some help from the "real" mechanics. The labor bill at this year's annual is going to be a bit ugly vs. prior years...