Vance Harral

Thanks, guys. I'm aware of the accident history, but hopeful it was repaired instead of scrapped. I may try e-mailing Ridgeaire.

This is a long shot, but I'm inspired by @Rmag's thread here. In the mid-80s, my father owned a share of N55FE, a 1965 M20E. Long before I took any formal flight training, he introduced me to basic control and navigation, and I have fond - if vague - memories of the airplane. It's registered to a Delaware corporation these days, and hasn't shown up on FlightAware since 2010. Thought I'd make a quick post here and just see if the current owner is on Mooneyspace. I'd love to see what N55FE looks like today.

These pictures here are great. The original A model evokes everything classic about Mooney lines and curves, and the individual specimens look well cared for. Congratulations to you all! mike20papa, I trained at KCLL and have a number of Coulter field landings in my logbook too. All from "back in the day" when I was a student at A&M. Love the paint and aluminum combo on your airplane. Wave at all the Aggies for me next time you're airborne.

Thanks air cooled dad. I see you have the exact model of actuator I do, with the infamous Adel clamp as well. That gives me at least some confidence our setup isn't just a shade-tree mechanic's kludge fix. Yetti, I shouldn't have said you have a "newer" actuator, just a "different" one. I assumed the LAC2116 in your airplane was newer than the LAC2114 in mine because the number was bigger. But that appears to not be the case. We have never adjusted the backlash on our actuator. I'm not entirely sure what you mean by that. I understand "backlash" to mean the space between the worm and pinion gears. Maybe you're referring to adjusting the emergency engagement lever? If so, no, we've never adjusted that either. All I know is the entire actuator was rebuilt by LASAR a few years back (they did more than just install the 40:1 gears). I'm inclined to assume it was adjusted at the time.

Can you elaborate on this particular point? Our unit actually failed the SB-190B inspection a few years ago when it had the 20:1 gears - both the worm gear and the pinion gear were scalloped to the point they had more than a half tooth of lash. This happened after about 8 years of dutifully pulling and re-greasing every 200-ish hours, so it wasn't due to old grease, just accumulated wear over 30 years. I definitely saw the gears wearing down over time, and I knew the unit was going to fail the inspection sooner or later. After 7 years on the 40:1 years I'm already starting to see very slight wear on them, though the system is still very tight, and probably decades away from failing an inspection. The wear rate anecdotally appears much slower to me vs. the 20:1 gears, so I'm happy to have the higher ratio. I'm aware it takes twice as long to raise and lower the gear, but the performance impact is negligible in practice. Curious why you think going to 40:1 gears is a negative.

I appreciate the ideas, Yetti. I may be able to get my mechanic to sign off on a minor mod that's more robust next time we have all this stuff apart. In the mean time, I know we have a few other 1976 M20F owners here on Mooneyspace. I'd love to see exactly what's installed in their airplanes. Having seen your picture where the L brackets just attach to the motor end plates - which my actuator has as well - I'm starting to wonder if that Adel clamp was really the factory solution after all. It's possible some prior owner lost the brackets and/or the magic unobtanium nuts, and the clamp is a kludge fix.

The picture in your post is an ITT LA11C2116 - different model than in my airplane (I think it's an even later follow-on to the LA11C2114). It obviously has the mounting holes for the bracket. Bracket(s), actually, I see yours has two. I agree it's a superior arrangement, I wish we had it. The only upside of having the LA11C2114 is that because it's technically not called out in the AD and SB, we don't have to strictly adhere to the 200 hour inspection limit. I don't worry about it if we go something like 210 hours between inspections, especially since our unit has been rebuilt with 40:1 gears.

My (limited) understanding is the second attach point has changed over the years, depending on M20 model and the exact landing gear actuator installed. The diagram in my parts manual actually shows a bracket attached to the back of the actuator to support the cable rather than an Adel clamp, but I believe that is specific to the Dukes 4196 actuator installed in earlier F models. By the time our airplane was built (1976 model), the Dukes was no longer available, and Mooney had moved to the ITT LA11C2114 actuator. That one lacks the bracket mounting holes shown in the parts manual diagram. I'm guessing the Adel clamp is a workaround. If yours doesn't have the clamp, I'd guess it has the bracket attached to the actuator. It's possible the attach point is on the fuselage as you describe. But in our airplane, the nearest fuselage stringer is too far away from the lever to make a good support point for the cable. Interestingly enough, the ITT LA11C2114 actuator in our airplane isn't actually called out in SB-190B or either of the landing gear actuator ADs. But we treat it as if it was, per advice from Don Maxwell.

All emergency gear systems have failure modes, and I'm not inclined to think the one in "vintage" electric gear Mooneys (I have an F model too) is any worse than others. In the honesty department, however, I'll say it has adjustment requirements that are something of a pain, and can be error-prone. You'll run into this because properly maintaining an electric gear F model requires pulling the gear actuator every year or two for inspection, to comply with SB M20-190B. On the plus side, this is an opportunity to inspect the whole system and understand how it works, check for wear, etc. On the minus side, it provides a regular opportunity to screw up the delicate adjustment of the emergency engagement cable. To wit, removing the actuator for inspection requires disconnecting the emergency extension engagement cable from the actuator. The cable attaches to the actuator at two locations. The first is the end of the cable which actually moves the engagement lever (first picture below). Moving the engagement control in the cockpit forward pulls this cable to engage the manual crank. Moving the cockpit control aft releases tension on the cable, and the spring you see in the photo is supposed to pull the lever to the disengage position. If the spring gets reinstalled with the ends swapped, the positioning and tension changes. Same if the complex collection of nuts and washers holding the cable gets re-ordered (and yes, it really is supposed to look like that, Rube-Goldberg-ish as it is). But arguably those things aren't a big deal. Just be careful, refer to the parts manual, and put everything back together the same way it came out, right? Well, sorta. In the second picture below, you'll see another attach point for the cable. It's effectively stiffened by a support bracket that's just a big Adel clamp around the housing of the gear motor. There is no detent in the housing to force the Adel clamp into a particular position, it just gets shoved on to the housing and tightened up. In fact, you can see mine is a bit crooked in the photo, that was done on purpose. When this clamp is re-installed, any minor change in position changes the relative location of the cable endpoint that attaches to the engage lever. Get it too far forward and the emergency extension gear only partially engages when activated (it grinds and/or binds up). Too far aft and the spring doesn't have enough tension to disengage the system, with the novel failure mode of the emergency gear handle whipping around wildly and beating your arms/legs when you retract the gear electrically. To make matters worse, the system has observer effect, wherein operation for testing can move the Adel clamp around if it's not very snug, resulting in mechanical hysteresis. Because of this, I'd never trust a single test of the system after a gear actuator R&R, I always do several. I'm sure Mooney-savvy shops do the same, but not every shop is Mooney-savvy. I've R&R'd our landing gear actuator numerous times over the last 13 years, and I consider myself pretty familiar with it. I'm always careful with removal and re-installation, even under the "adult supervision" of an A&P. And yet, about every other time I do so, a bit of tweaking is necessary to get the system adjusted properly so it reliably engages and disengages over multiple tests. I've seen it misbehave when not perfectly adjusted (that's how I know what the failure modes are). I've seen it work on a first test and not on a second one. And if you need convincing this can fail "in real life", I refer you to the gear-up landing by a prior owner in our logbooks, which was blamed on this exact mechanism being mal-adjusted. The pilot ran out of electrons, and when he attempted to lower the gear manually, the engagement lever didn't fully engage, and the crank jammed. So... while I don't know your buddy's actual experience with Mooneys or exactly what his concern is, I think it's fair to talk about vulnerabilities in the system. I think the basic idea of using a manual gear on the other end of the motor shaft to turn the system is sound, but the way that gear is engaged/disengaged doesn't seem especially well designed to me. To be fair, the factory probably didn't envision everyone pulling the landing gear actuator out of the airplane every year or two when the system was designed, but that's the situation we have now.

Seconded. We're very happy with our EI AV-17, but there are other choices too.

That's interesting. The maintenance manual for my 1976 F model lacks detail on this, but your comment moved me to go look in the more detailed maintenance manual for the 1977 J model - which I believe uses exactly the same senders and gauges as my airplane. That manual does have a calibration procedure for the gauges. It says the gauge must match actual fuel level within 1/2 needle width at empty (zero usable fuel), 1/4, 1/2, 3/4, and full. I'm not sitting in front of the airplane, but my recollection is there's roughly 1.5 inches of span between the E and F marks on the gauge, and the needle is about 1/16" (0.0625") wide. A 1/2 needle width error would therefore be about 0.03125/1.5 = 0.021, or about 2%. The catch is, the fill procedure allows for -1/+2 gallons of error in the 8 gallon increments used to fill the tank to the 1/2/3/4-quarter levels. So at the quarter tank mark, for example, you could have as much as 10 gallons instead of 8, which is 10/32=0.3125 of a full tank. The needle could be 1/2 needle width below the 1/4 mark and still meet spec. In that case, the needle would indicate ((1.5/4)-.03125)/1.5 = 0.2292 of a full tank. That's an error of 0.3125-0.2292=0.0833 of a tank, or about 8%. I won't argue with the characterization of 8% as "lax" compared with the 3% spec in TSO-C55a. But we're still talking about error in the range of a needle width or so. That's a lot more accurate than I think most pilots would guess is required of the fuel gauges.

My knowledge of fuel indicator regulations doesn't come from vast professional experience, just an hour or so of actually reading the regulations and associated ACs, motivated by a "that can't be right" skepticism of the myth. I'm not inclined to apologize for holding other pilots to that same standard, but it's not my intent to be a jerk and/or a know-it all. I do apologize for any brusqueness, and freely admit plenty of personal ignorance on other subjects. Your specific question is an opportunity to admit ignorance myself. TSO-C55a specifies accuracy tolerances of 0.75%, 2%, and 3% for class 1/2/3 indicators, respectively. I don't know what constitutes a class 1 vs. 2 vs. 3 sensor, that appears to be defined in an SAE publication I haven't read. Maybe fuellevel can explain. Even three percent is a pretty tight constraint. That's less than one gallon in the 26-gallon tanks in each of the wings on my airplane. I'd be unlikely to notice or care if my gauges read half tanks when there were really 14 gallons in the tank instead of 13, even though that's technically beyond airworthy tolerances. But if the gauges showed 3/4 tanks when the dipstick showed 10 gallons, I'd consider it a malfunction to be fixed immediately.

With respect - and I mean that honestly - I don't think you understand the meaning of the word "accuracy" in the context of measuring devices. The part of the regulation you quoted says "zero". It doesn't say "zero plus or minus one gallon", or "zero plus or minus one percent of the total fuel quantity", or anything else of the sort. Those would be accuracy constraints. The point of subpart (b)(1) is clearly to define what zero means, not to specify the accuracy of the measuring device which indicates it. You're grasping for a definition which fits the funny joke about the fuel gauges only having to be accurate at zero, but that's neither the letter nor the intent of the regulation. But don't take my word for it. The FAA's guidance to people who certify airplanes to part 23 regulations is laid out in AC 23-17C. Here's a particularly telling paragraph from that publication, from page 269: Fuel quantity indicators are also governed by § 23.1301, as are all 14 CFR, part 23 Subpart F appliances. This regulation requires the installed indicators function as designed and not create a hazard in their operation. This precludes indicators that read higher than the actual fuel level since this would constitute a hazard. The AC also makes reference to any changes in fuel quantity indicators needing to meet the standards of TSO-C55a, as fuellevel mentioned above. That TSO details the required accuracy for various classes of fuel and oil quantity indicators. It doesn't contain the word "zero" at all. The accuracy requirements it specifies apply across the full scale of the indicator. I grant that those publications didn't exist in 1965. But you have to really grasp at straws to claim the FAA's position even in the CAR 3 days allowed fuel gauges to be wildly in error at any level above zero usable fuel. That was never the intent or implementation, and aircraft with grossly inaccurate fuel gauges have never been legally airworthy.

Yes, that's my understanding. I suppose it's possible Mooney and the FAA pencil-whipped the certification process, I can't prove they didn't. But it's unlikely. CAR 3, specifically CAR 3.672 which isn't much different from FAR 23.1337. My point isn't a question of "trust", it's just about what the certification standards require. That said, ignoring fuel gauges because you think they're so inaccurate as to be worthless removes a valuable tool from your fuel management strategy. It's akin to saying you don't trust your attitude indicator, but it's acceptable because you have needle, ball, and airspeed. Or that you don't trust your nav radio but it's acceptable because you have an iPad. There are certainly pilots that do such things and I'm not going to be holier-than-thou about it. But such aircraft aren't in compliance with their basis for certification, and are less safe than aircraft with all redundant systems functioning as designed. If your fuel gauges are that far off, the gauges and/or the senders need servicing. They certainly were not designed to such lax standards. You seem to have the impression it's not possible to maintain the fuel gauges to reasonably accurate standards because they were never designed to be accurate in the first place. That's just not the case. Sure, the wiper-arm potentiometers on the sender wear out and need to be serviced or replaced, the springs on the gauges themselves may wear over time, etc. But those are long-term maintenance requirements, not design limitations. Servicing your fuel indicating system is no different than replacing shock disks, resealing fuel tanks, replacing trim jack screws, or any other PITA issue we'd all like to avoid, but which are in fact the standard of care for airworthiness.

No other regulation is needed for clarification. FAR 23.1337 doesn't specify an accuracy constraint, but neither does any other powerplant gauge regulation in Subpart F. In fact, 23.1337(b)(1) doesn't specify an accuracy constraint for "zero", for that matter. What 23.1337 does say is, "An indicator calibrated in appropriate units and clearly marked to indicate those units must be used." No reasonable interpretation of "calibrated" would allow for wild inaccuracies in fuel gauges across their full range. If you actually read all of 23.1337 in context, it's clear sub-part (b)(1) is written to address the difference between zero absolute fuel vs. zero usable fuel. My guess is someone made a clever joke about 23.1337(b)(1) a long time ago, and it somehow "went viral" long before the modern interpretation of that phrase. For anyone tempted to devolve into pedantic parsing of the absolute letter of 23.1337, just look at the big picture. FAR 23 is filled with regulatory requirements about instruments. Most use essentially the same type of "calibration" language, and lack any numerically-defined accuracy or precision constraints. But we don't make silly arguments that oil pressure or CHT or tachometer gauges have absurdly lax accuracy standards. Grossly inaccurate CHT/tach/etc. gauges certainly wouldn't pass muster with a DER or other certification authority, despite the lack of specific accuracy/precision constraints. Neither would fuel gauges.

Completely incorrect, please stop propagating this old wives' tale. The certification standards require fuel gauges to be accurate throughout the complete range of the indicator. The myth comes from a misunderstanding of the sub-part dealing with usable vs. unusable fuel. I don't mean to be a jerk about it, but propagation of this OWT is a substantial reason fuel gauges get signed off when they're actually unairworthy. This just further propagates the myth they're less reliable or less important than other critical indicators. I'm sure this drives the professionals absolutely nuts. The OEM fuel gauges in your Mooney and other GA aircraft are designed to be reasonably accurate throughout their range. They need to be, because gauges are the only mechanism that will detect a developing, in-flight fuel system leak. Totalizers and timers are of course excellent safety guards against fuel starvation, but they're meant to supplement the gauges, not replace them. If your gauges are inaccurate, your aircraft isn't in compliance with its type certificate, and it needs maintenance. Kudos to the OP for wanting his fuel gauges to be accurate, and to businesses like CIES for providing technology that improves accuracy and reliability.

I'm aware they're not the cheapest in town by any stretch. But as far as I know they're the only shop in Colorado that both knows what's involved in patching a wet wing, and are willing and able to do so (at least as of a few years ago). The other options seem to be to fly out of state, or take your chances with a mechanic that lacks the experience to know that "Nah, too much trouble" is a pretty defensible response. Frankly, when you're staring at something in the neighborhood of $10,000 including travel expenses to get a full strip-and-reseal, anything seems cheap.

CaptG, are you flying out of KAPA? Arapahoe Aero (http://www.arapahoeaero.com/) is right there on the field. They've done a couple of fuel tank patches for us over the last 13 years. Relatively inexpensive and the patch work has held up well. Patch work isn't a cure-all, and some people say it's only delaying the inevitable full strip/reseal. We've been happy with our decision to have patches done, though, as the tab was under $1000 each time. That's pretty cheap compared to quotes I've seen from name-brand shops that are north of $8000, not including travel expenses. On the other hand, while the patches from Arapahoe Aero are holding up well, we have new seeps on both sides from other areas Arapahoe Aero hasn't (yet) touched. We've been mulling over another patch vs. a full strip and reseal for over a year. In the mean time, we're simply living with it. Both the Mooney service manual and AC43-13 have specific sections on the airworthiness of fuel leaks. They allow for a certain leak rate, you don't have to be 100% leak-free to be airworthy.

No integrated audio panel, but it does have a feature that allows you to monitor audio on the standby frequency. This is almost like having an additional listen-only COM radio. I use the feature to start monitoring tower/CTAF early when I'm still talking to approach, or to monitor radio traffic when I'm halfway between two closely-spaced airports.

I'm not sure I'd agree with the sentiment gear disks aren't terribly expensive. Present-day pricing is about $115 each, and you need 4 on each main and 3 on the nose. That's a $1265 hit if you do them all, and that doesn't include labor. We just re-did the main gear pucks on our airplane, and the job actually cost more than our last fuel tank patch, which was more than 5 years ago. I've also noticed the cost of the disks seems to rise at about double the inflation rate. This is the second round of disks for us. The first round was about 10 years ago and the disks were only about $85 apiece back then. The price seems to go up about $5/disk every year.

If you're serious about having a partner, recommend you find the partner first and buy the aircraft together, vs. the other way around. In addition to having more resources with which to purchase, there are other compelling reasons. First, the process of choosing a specific aircraft, traveling to see it, inspecting it, agreeing on a price, and deciding how much to immediately invest in upgrades upon purchase, touches all the stress points that tend to make partnerships go bad. If you make it through that process with another person, odds are good you've found a compatible partner. If the relationship goes south while you're looking, you can bail out before anyone invests equity that must be reconciled in a possibly adversarial manner. Second, partnerships work best when all partners feel equally attached to and emotionally invested in the aircraft. The danger in acquiring the aircraft yourself first and finding a partner afterward, is that you'll think of the airplane as "your" baby, that you're merely letting someone else "borrow". That's not healthy for the partnership. I appreciate that you may just want to do one thing at a time, and you're excited about buying an airplane so you want to do that first. Not suggesting any malicious intent. But as a person who has participated in aircraft partnerships, a partnership ad from a person who acquired the aircraft less than a year ago is a bit of a red flag. It gives off a vibe like, "Now that I've chosen the airplane, the tie-down/hangar spot, the upgrades, gotten used to it, and decided exactly how I think it should be operated, wouldn't you like to come share half the cost?" Whether you feel that sentiment yourself or not, it does exist in the community. Therefore, buying first reduces the pool of partners who might be interested. Just my $0.02 on partnerships. Whether you go that route or not, I'm excited for you - enjoy the search!

Thanks. I've looked at their online catalog and did not see them, but I've never actually contacted them to ask directly. Sounds like they do stock them.

While we're on the subject, does anyone have a source for these vents? I removed and patched cracks in ours a few years ago, but they've developed new cracks. And one of them was smashed to smithereens by an errant headset removal. I'd actually like to replace them with something other than plastic, but barring that, I'd take salvage, new stock, or maybe even an owner-produced 3D printed part (anyone have a shapeways link?)

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.