Vance Harral

No, I didn't get any response. In consultation with the mechanics, we decided to clean up the existing bolt and nut with a wire wheel and re-install. The wire wheel removes any cadmium plating left on the parts (of which I suspect there was virtually none left anyway). So after cleanup, I primed and painted the nut, and the head and end of the bolt for corrosion protection, then installed it with a heavy dose of LPS-3 corrosion protectant all around. I'm confident the old bolt and nut have good holding strength, just wanted to replace with new for better corrosion protection. Instead, I'll keep a close eye on the reinstalled bolt over the next year and look for signs of corrosion.

Those chemical spot detectors are better than nothing. But they don't last long and they're fragile. Some brands (including the Sporty's one) have a useful life as short as 30 days, and all of them can be rendered inert (won't work) by cleaners and solvents routinely used in aircraft cleaning and maintenance. If you're serious about CO detection, an electronic detector is a more robust choice. There's an AvWeb article on this at http://www.avweb.com/news/aeromed/186016-1.html. It was written in 2003, so the makes and models of "best" detectors have changed, but the general information is still useful.

Yes, all the caution you mention is appropriate and I appreciate it. That's why I'm asking for ideas here on the forum - to increase safety, not just to make the job easier. Draining the tanks isn't impossible, but highly impractical given the particulars of the shop, and has it's own risks to boot. To be clear, my vacuum idea involves a hand operated vacuum pump, of the type you'd use to bleed brakes. No motor, no electricity of any kind. I did ground the airframe and I know where the extinguishers are. I employ the buddy system with the shop mechanics to minimize risk.

Our fuel selector is at LASAR right now for overhaul. Removing it from the airplane was a fairly miserable experience. Despite my best "quick draw" routine, fuel rained all over me from the time I first loosened the lines from the tank until I got a plug installed. Twice, of course - once for each side. When it comes time to reinstall, I'm wondering if there's a trick to make the job easier. In particular, I was thinking of trying to draw a (very) light vacuum on the tanks from the fuel tank vent. I have a little hand-operated vacuum pump and could attach it to the vent with some tubing. If anyone has tried this or has some other tip, I'm all ears.

Have the main gear shock disk towers off the airplane right now for shock disk replacement, including the bolt/bushing/nut that attaches the tower to the truss. All the hardware is - not unexpectedly - showing some light surface corrosion. We stripped, bead blasted and repainted the towers to address this. I'd also like to replace the bolt, bushing, and nut. The nut is an AN365-918 which can be overnighted from Spruce or maybe even obtained locally. But the bolt and bushing have Mooney-specific part numbers. As Mooney and the local service centers are closed today, I'm wondering if anyone knows if these parts are cross referenced to some standard part number. I'm not particularly hopeful about the bushing, but the bolt just seems like a standard AN bolt, especially given that it takes an AN nut. I'm a little surprised it has a Mooney-specific part number in the parts manual. Does anyone know a quick source for these parts? Alternatively, any advice for cleaning up the bolt and nut I already have? I can run it on a wire wheel, but that would strip any cad-plating still left. I'm not sure if painting the nut and the head of the bolt after doing so is kosher, or particularly useful for corrosion protection. Any advice/tips would be appreciated.

PM me next time it's there, would love to come see it. I live a stone's throw from KEIK, though our airplane actually resides up in Longmont.

Or in my case had a return headwind so bad the tailwind on the way there isn't much comfort. My airplane partner and I flew from Denver down to San Antonio a week ago. Our airplane typically cruises about 145 KTAS. Saw 155 ground speed on the way down. On the return leg from San Antonio to Abilene, ground speed was about 70 knots. No, that's not a typo. Saw 35 knots ground speed in the climbout. Could have bought 10-20 knots at a lower altitude, but it wasn't enough to justify getting pounded by the turbulence for hours on end. Was pretty smooth at 6000', so we decided to live with highway speeds. Took all day to get home (winds were better further north), but with two pilots to fly legs, it wasn't unpleasant. I told my buddy we should fly a 360 just to see our groundspeed downwind and take a photo, but he said, "No way - do you know how long it would take to make up the lost ground?!"

It likely was "automatic". Many Mooneys have a spring interconnect between the aileron and rudder such that aileron input automatically applies a bit of rudder, and vice versa. Still oughtta keep your feet on the pedals, though. ;-)

Not to slight the MAPA guide, but zero flaps is not we use for IFR approaches in our 1976 F model, and it sounds strange to me. The MP settings you're quoting from the guide also sound high to me. But again, not really questioning the MAPA suggestions, just letting you know we fly differently. The standard approach sequence used by all four partners in our airplane involves extending flaps to the "takeoff" setting (we call it "approach flaps") and slowing to 105 MIAS prior to the FAF. This requires about 13-14" of MP depending on weight and conditions, and achieves level flight with good control response. We typically use 2500 RPM, and that may be part of the difference vs. the MAPA suggestions. Anyway, at the FAF (or when one dot high on glideslope intercept), gear down is selected to produce a 500 fpm descent. In zero wind conditions, these numbers keep us right on glideslope. With a head or tailwind, we'll increase or decrease the MP by about 0.5", respectively. For IFR beginners or when rusty, I advocate 105 MIAS and approach flaps well before the approach begins. For true beginners I advocate this even prior to a procedure turn. Later on, it's reasonable to introduce the concept of slowing and extending approach flaps during a procedure turn. But regardless of how you get there, the goal is to slow down and establish stable, level flight with approach flaps, well before navigating the final approach segment. After lots of practice (maybe after obtaining the rating in your case), you can experiment with flying the initial approach faster. For example, I know in our airplane it takes about 90 seconds to slow from max cruise speed clean, to 105 MIAS with gear and flaps down. When I'm on my "A" game (lots of recent practice), I can fly approaches at full cruise speed until I'm 90 seconds out from the FAF, then pull the power and extend the flaps and gear at flap/gear speed. The goal is to enter a descent with approach flaps and gear down right at the FAF. This is challenging, as you must maintain level flight while changing the configuration, and there's an art to deciding when to pull the power (you want to see somewhat less than 90 seconds to the FAF on the GPS, because you'll be slowing between the present position and the FAF). It's also almost never necessary, but it's fun, and I throw it in for the "you've got to keep your approach speed up to get into large airports" crowd. I'm aware many pilots advocate flying the final approach sequence faster than the "standard" 90 knots. In some cases these pilots say the airplane feels mushy and unresponsive at the lower speed, and feels nose-high. That may have a lot to do with whether they've already extended the flaps. Partial flaps allow for a lower deck angle at the same speed, and - in my opinion - result in more stable control "feel" during the approach. Most importantly, while landings with any flap position are reasonable in a Mooney, I like flying the approach with "approach" (takeoff) flaps because it's no big deal if you don't touch them between the FAF and the landing. The touchdown speed and deck angle in a half-flap landing isn't dramatically different from a full-flap landing, and if you're really flying a precision approach to minimums in the clag, you're likely to be setting down on a lengthy runway anyway.

Sure, every charging system has some minimum RPM, below which it can not provide enough current to sustain system load. But the whole "trick" about alternators (vs. generators) is they can increase current to the field circuit as RPM decreases, providing more charging "oomph" and sustaining the desired system voltage at lower RPMs. In our F model, the alternator can sustain a system voltage of around 13.7 volts all the way down to an RPM below which we don't idle anyway (oil splash to the camshaft isn't very effective much below 800-900 RPM). I've read stories here and elsewhere about aircraft system voltage warnings at idle RPM, but I look on them with something of a raised eyebrow. The problem makes sense in older airplanes equipped with generators. But in "modern" airplanes with alternators - including the M20K - I frankly don't get it. It seems to me either the charging systems in those airplanes aren't working properly (bad diodes, improperly adjusted regulator, etc.), or they're grossly under-designed. I'm happy to be corrected on the latter point, I do understand aircraft electrical systems have constraints automotive systems don't - e.g. weight. But I'm still inclined to think if you're constantly getting low voltage warnings at idle in an alternator-equippped airplane, you shouldn't automatically assume it's "normal", even if others report the same thing.

That doesn't sound right. Especially for an airplane equipped with an alternator, which I presume your M20K has. If it's really that low at idle, that lends a little more credence to the programming voltage theory. But again, I'm no expert on the KX-165. In particular, I don't know when/how often it writes the "current" frequencies to nonvolatile memory.

Long shot, but you might also check your battery bus voltage (i.e. what is your regulator putting out when the alternator/generator is running), as well as your power connections. Nonvolatile memory of the era during which the KX-165 was designed and produced (typically EEPROM) requires a programming voltage higher than the operating bus voltage for the device. Typically this is generated by a charge pump, but the pump can only achieve so much of an increase. If the bus voltage is low or the power connection weak, the device can "work", but fail to update NVRAM due to low programming voltage. I've seen this behavior in a couple of different avionics gizmos over the years, most notably our Shadin Miniflo fuel totalizer. When fuel is added, the totalizer must be updated with the engine running and the alternator driving the bus to about 13.6V. If you just turn on the master, program the Shadin with the bus voltage at ~12.8V, and turn the master off, there is a 50/50 chance it will fail to "remember" the new fuel level on the next power up. I'm no expert on the KX-165, but I wouldn't be surprised if it works the same way, particularly given the user manual description Hyett6420 posted above.

Cliff, did it all come apart with conventional bolts and screws, or is anything riveted?

With the recent spate of trim issues, I'll be taking an extra-close look at the stabilizer trim system on our 1976 F model during the owner-assisted annual we start next week. Just seems like a good idea. No electric trim in our airplane, everything is manual. The jack screw and hinges at the tail end aren't especially difficult to inspect and lube once you get the boot out of the way, I do that every annual. The shafts and universal joints which connect the tail components to the cabin end of the system are easily accessible for inspection and lube as well. That leaves the cabin end: the trim wheel itself, and the chain and gear train which connect it to the first segment of the trim shafts. While it's not technically impossible to access these components (I try to get some grease on the chain at every annual), most of the moving parts are behind supports or inside what the parts manual calls a "gear box assembly". I've never had this apart or really lubricated it well during the years we've owned the airplane. I have a sneaking suspicion the gearbox and gears/bearings/etc. are full of old dried grease, sludgy lube, and dirt. In a perfect world, I'd like to do the same sort of inspect/clean/re-lube we do on our electric landing gear actuator gearbox: remove the assembly, open the covers, flush everything with solvent, inspect, and re-lubricate. But this seems like a difficult job with the trim gearbox, prone to causing a maintenance-induced failure. What do the rest of you out in MooneySpace do with this part of the trim assembly? Remove it for a full clean/re-lube? Just shoot some lube in whatever access hole you can find with a straw? My parts and service manuals don't say anything about it that I can find. Would like to hear about best practices from those in the know.

How often are you flying your airplane, and have you actually had "winter battery issues", or is it just a precaution? I'm not advocating against battery minders. They provide real value for airplanes that go long periods of time without cranking and/or live in very extreme environments. But... I suspect they're sometimes (often?) used when not really warranted. I'll offer you a data point: we got 8+ years of life from our last Concorde RG-35 battery, having never used a battery minder. The airplane is hangared in Colorado, where it's not unusual to see subzero temps during the winter (it does stay a little warmer inside the hangar, but still plenty cold). Our airplane typically flies about once a week, but it's not unusual for it to sit for 2-3 weeks in the winter every once in a while. During that 8+ year span, we stressed the battery significantly on one occasion, when a failure of the shower-of-sparks system at a remote airport caused us to crank the battery until nearly dead. Even with all that time, cold, and the crank-until-depleted incident, we never had a problem with the battery itself, either with cranking or during capacity tests. So it's very clear to me from actual data that we have no need for a battery minder on our airplane. An airplane that regularly sits for months at a time or has a different battery (or a 24V system with two batteries) is maybe a different story - my anecdote applies only to our particular situation. But I bring it up because there's a good chance you don't "need" a battery minder if you fly regularly, or even semi-regularly. You may find it's much easier to just leave your battery minder unplugged and avoid the debate with your hangar mates, vs. trying to convince them the risk is low. That's especially true with human nature being what it is. I'd bet it doesn't matter what kind of risk analysis data you present. My guess is your hangar mates have already decided they don't like the battery minder, and you're probably not going to convince them otherwise. Just my $0.02.

I can't emphasize enough what an impression this behavior made on me. When Cleon was giving me instruction for my CFI, he regularly reminded me that he "didn't know everything", asked for my input on things like terminology and teaching approaches, and debriefed our lessons by actively seeking critique on his own teaching. This from a guy with thousands of hours in a huge range of aircraft, to whom my experience matches up like the proverbial gnat. I like to think one of the ways I honor Cleon is by seeking input from my own students, and maintaining a sense of humility regardless of experience. We're all just students at some level, and Cleon was such a great example of that positive attitude. Thanks for reminding me of that today.

I attended Cleon's memorial service last month here in Longmont. He was indeed a great meteorologist, pilot, instructor, builder, and - most importantly - friend. He taught all the partners in our Mooney in one capacity or another - basic transition training, instrument ratings, even my CFI. One of the last conversations I had with him was regarding an issue with a student, and he was helpful as always. It was a privilege to know him, and to have flown with him. You'll all be pleased to know Cleon was flying right up until a few weeks before he left us. He recently completed building a Rans S-19, which was as impeccably constructed as you might imagine. A friend of his who also built an S-19 spoke at length during the memorial, about how valuable Cleon had been helping him construct his airplane, and fly it thereafter. There were many pictures in albums at the memorial of Cleon's life in aviation, flying everything from that S-19, to Learjets, with a couple of Mooneys in there, too. Cleon was a great role model as an aviator, and the local aviation community was well represented at his service. For those of you so inclined, Cleon asked anyone wishing to remember him consider making a contribution to EAA chapter 43: http://www.ahlbergfuneralchapel.com/book-of-memories/2791439/biter-cleon/obituary.php But as great an aviator as Cleon was, he was an even better person. Cordial, humble, informative, helpful, everything we aspire to be. I miss my friend, and I grieve with Toni and the rest of his family. Godspeed, sir.

I'll start the bidding at $100 plus shipping costs for the strip gauges. We have those same gauges in our airplane and I'd like to keep a set of backups.

Thanks to all for the replies so far. I'm open to suggestions on a different lubricant. The official maintenance manual isn't helpful here, as this is one of those cases where the 1976 F was actually designed with some J-model parts. The yokes and shafts in our airplane are factory original (as far as I know from the logs). Hence AD 77-17-04 still technically applies by model and serial number, even if it's arguably unintentional. The F maintenance manual calls for powdered graphite lubricant on the "control column bearing ball", but our airplane doesn't have a ball at that spot like the older models do. The J maintenance manual calls for Triflo (teflon) spray, which I'm willing to try. I confess I assumed there wasn't much difference between Triflo and garden-variety silicone spray, but perhaps I'm mistaken. As for lubricants that last "a long time", my general rule of thumb is heavier lubricants (more oil/grease content) last longer, but they're also more prone to gathering dirt and dust. I've considered trying something like LPS-1 or LPS-2 on the yoke shafts, but I just don't want oily stuff around the interior. Sooner or later it gets on your fingers, then on the upholstery, then on the avionics screens, etc. But again, I'm no expert here - open to suggestions. The thing is, we've been using silicone spray on the yoke shafts per mechanic's advice for over a decade, and this problem has only cropped up in the last couple of years. That's what makes me think the block is wearing.

In photo 1 below, the red arrow points to the phenolic block which supports the right side yoke shaft, just aft of the panel. It's mounted to the steel tubing that also holds the instrument panel itself. Photo 2 is a shot from many moons ago during an avionics upgrade, which shows the block a little more clearly (in the red circle). Periodically when moving the elevator during preflight inspection, the yoke shaft "chatters" in this block. It's been doing so for a couple of years now. When it does, we break out the silicone spray, use it to lubricate the yoke shafts, and the chattering goes away for a while. But it always comes back. At one point I took a close look and found what's arguably a little excess play in the block. As far as I know it's original equipment, and I suspect it's worn a bit over 40 years of service. This seems to be a likely root cause of the chattering. So I dutifully ordered a new phenolic block from LASAR to replace it. But the mechanic and I gave up on the job when we discovered there is (apparently) no way to do so without disassembling the instrument panel, like in photo 2. If I had a time machine, I'd certainly go back and replace it during the avionics upgrade! Has anyone figured out a way to replace these things easily? It's simple enough to unscrew the block from the steel tubing, but then you just have a loose block which you can't slide off the shaft. It won't slide off the back end due to the control linkage welds. It won't slide off the front end (after removing the yoke) because it won't fit through the hole in the instrument panel. I think some year models have a bigger hole in the panel here - maybe ours could be dremeled out as a minor mod? Or I guess we could just wait for the next avionics upgrade, but that's likely a long time away. Anyway, this seems like the kind of thing someone has a clever solution for. Any experts out there? Alternatively, is there a different cause/fix for the chattering problem? I was just guessing a new phenolic block would fix it, I don't really know that for certain. The yoke shaft itself is in good shape (recent inspection per AD 77-17-04), and I'm confident it's binding at the phenolic block, not anywhere else in the linkages. I suppose it's possible there's just dirt and grime in the block, and the play would otherwise be OK without it. But I'm not sure how you'd clean it out without causing more problems than you're solving. Any tips or advice would be appreciated.

Yeah, the nut plates are spendier, but fortunately it seems the screw is usually the cause of binding vs. the nut plate. I like the washer idea, but I confess we don't bother with it. A lot of that has to do with the paint on our airplane being pretty old and beat up (still looks good from 50' away!). The paint is already worn away under the screw head on most of our panels. I'll probably feel differently about it if we ever get the airplane prettied up with fresh paint. For all you guys with less-than-pristine cosmetics, there's a certain luxury in not having a showpiece when you're in the maintenance hangar. I'm able to get inspection plates and belly panels off a lot quicker, since I don't have to be quite so paranoid about the occasional paint scratch from a slipped bit. It's been nice to learn screw-craft on a less-pretty airplane. After 12 years of owner-assist annuals, I like to think I've reached the point where I can make pretty good judgement calls on where I can use drill drivers vs. breaking out the hand tools, when I need a new bit, etc.

Thanks for the great info, Steve (and danders). The labor doesn't look too bad, especially with some owner-assist grunt work. I like to do as much of that as possible, and I have a mechanic who's amicable to that. But I also have a day job, so my DIY work typically has to be carved up into 2-3 hour chunks. Makes it a little harder to commit to bigger jobs, just due to the total downtime if things stretch out. That's actually our biggest barrier to a "no apologies" overhaul of the gear hardware. As a partnership, we have a general obligation to try to minimize downtime, so everyone can fly. Not that we skimp on maintenance, but the partnership results in a reasonable and appropriate amount of "if it ain't broke don't fix it" pressure. We take a certain pride in the idea our airplane is a work (fun) horse, not a showpiece. Congratulations on having chosen an airplane in the optimum serial number range. We're pretty far across the country from each other, otherwise I'd suggest a 1976 M20F meet-up this year! Maybe we still should - we have airplanes at our disposal, after all...

That looks great, Chupacabra. Can you and/or deanders share the approximate hours of labor involved (which I'm sure is the bulk of the cost, not the paint/alodyne)? I know it's "a lot", but would like to get an approximate number to use as a basis for discussion with my airplane partners.

I agree, the value is in the information, not the media on which it's contained. But it'll be tough to get to full-value acceptance of digital copies, because value is market-driven, not mandated. After all, the regs already allow you to discard most of the information typically found in an airframe logbook. I think there are likely to be curmudgeons for some time who think a digital copy is somehow more subject to shenanigans than paper, and/or that a lack of paper demonstrates a lower standard of care. Even buyers who don't care either way may want to protect themselves against said curmudgeons when they sell in the future. Hence there's value in paper logs with respect to sales price, or at least to the number of buyers willing to consider the aircraft. As for me, I'm not sure why curmudgeons think paper forgeries are more difficult than electronic ones. But I'm not going to discard our paper logbooks just to stand on principle. [Note: all due respect to curmudgeonry, I'm occasionally a curmudgeon myself. ]

I've always wondered about this. If I understand you correctly, the paint shop didn't remove the trusses, but rather painted them in place? Did they strip the old paint off first, or just "scuff and shoot"? Seems like it would be difficult to paint the gear in-situ, without getting paint into all the moving parts.