Vance Harral

I'm interested.

As everyone notes, cabin width, length, and height numbers are comparable or better to the competition. But there are some things that legitimately make the cabin feel smaller to a lot of people. First, the Mooney fuselage is rounded at the top, unlike the square roof of Brand C and the less-rounded roof of other brands. This gives at least the feel and in some cases the actual reality of impingement on the shoulders and heads of tall guys, despite cabin width at the hips and elbows being comparable to the competition. Second, the seating is low with your legs stretched out further, whereas other brands tend to have higher seats and a more upright seating position. Some people really like the "sports car" seating design in the Mooney, but not everyone. I'd be 100% OK with it if it weren't for the way my calf and knee rub on the nose wheel well, which is a minor annoyance I don't get in other airplanes. Finally, and IMO most significant, with the seat positioned to reach the rudder pedals, the instrument panel is closer to you than other brands. I like the way this makes even instruments on the far side of the panel easily visible. But I can understand why a close instrument panel feels "cramped" to some, especially if they're the type to worry about banging their head on the panel in an accident. Whether you're affected by any of the above or not, I think we can agree cabin comfort is a personal thing that varies a lot among individuals. People who have only heard about "cramped" Mooneys without sitting in them are often pleasantly surprised, but complaints from people who've actually climbed in and made their own judgment shouldn't be dismissed.

That's a good question, and I'm sorry to say I don't know the answer. I'm fixated on the IO-360 series since that's what's in my airplane, and forgot C and G models are carbureted. The service instruction relates to detonation margin, which perhaps is only a concern in the 200hp IO-360s in the E/F/J.

There is a Lycoming Service Instruction which recommends changing the timing on the Lycoming IO-360 series from 25 BTDC to 20 BTDC. There's a lot of debate about whether it's a good idea to follow the service instruction. That's up to you. But the most likely explanation for your timing being "significantly off" is that it was deliberately set for 20 BTDC the last time it was adjusted.

Just make sure you actually use the "backup" switch from time to time. If you don't, the contacts tend to oxidize, such that the backup will fail you when you really need it. Some folks argue a single DPST switch is a better solution than two SPST switches for exactly this reason: both sets of contacts are exercised every time the switch lever is operated. It's a good theory, but you're unlikely to notice when/if one set of contacts goes. That effectively puts you back to having a single SPST switch.

All switches designed for high current and/or inductance are spring-loaded, whether they're relays or hand-operated switches. The typical non-relay avionics master switch has the same "quick" open/close behavior as an avionics master relay.

Careful, not all avionics master switch installations use relays. In older airplanes, sometimes an avionics shop will simply wire a large, high-current switch (or two) directly between the main bus and the avionics bus. There are pros and cons to this approach vs. using a relay. I won't get into that debate right now, but if you're debugging an avionics master issue, you really need to get behind the panel and see what the switch is connected to. There may or may not be a relay.

That looks like a backup avionics master switch, given that it's immediately adjacent to the regular avionics master. The idea is that two switches are wired in parallel, and either one can enable the avionics bus. If one switch fails, the other one may be used to keep the power on. Typically used in an installation where a high-current switch directly connects power to the avionics bus (as opposed to systems where the avionics master is a low-current device that controls a relay).

I find a hacksaw works best for cutting the paper element out of the housing: quick, easy, and safe. It does leave "fuzz" at the cut, which I guess you could argue is a distraction when looking for foreign material, but I don't think it's a major issue.

In our F model, the MP gain from opening the ram air vs. closed with a Brackett filter is even less than that. I can see the gauge move a smidge, but not a full inch. And some of that benefit isn't even from filter vs. no filter. The ram-air-open path goes efficiently straight into the intake (hence the "ram" in ram-air), whereas the normal path through the filter requires the air to follow an S-shaped path to the intake. So I'm pretty sure if I just took the Bracket filter off altogether, I'd see 1/2" MP or less vs. having the filter installed. A "better" filter can't improve on that, so not worth the cost IMO. I'm not saying you couldn't win a drag race by a quarter knot in otherwise identical airframes with a K&R filter. But it's not going to get you to a destination any meaningful amount of time faster, nor be the difference in clearing that tree at the end of the runway.

I think there are so many different ways of mounting the microswitch in the various models and years that you just have to look at your particular installation to figure out how it works. In our '76F with the quadrant throttle, we're lucky: the position of the switch can actually be set with a set screw, which is accessible via a hole in the quadrant. Literally a few seconds to tweak it. Someone above mentioned a system where the switch is triggered by actual manifold pressure. I've never seen one like that and would be interested to know how it works. As far as I know, (almost) all installation are just based on throttle position. Note that the exact MAP you get for a given throttle position varies with atmospheric conditions. The nit-picker in me would argue you set the switch for about "N" inches of MAP, not any specific value. If you feel like having a bar argument, try bringing up what "N" should be in the context of an airplane that makes landings everywhere from Dutch Harbor in January to Leadville in August.

Ugh, tell me about it. We have a Garmin 396 strapped to the yoke whose sole purpose at this point is to provide audio terrain warnings. It was cool when new, but at this point everything it can do is better handled through hardware in the panel or on an iPad. I'd just as soon get it off the yoke and sell it or give it away. But I'm not willing to give up audio terrain warnings, and Big G wants literally *thousands* of dollars to unlock TAWS on our GTN650. :-(

It's worth referencing your parts manual to see what's supposed to be there. Speaking only for the 1976 F model, I used to think the airplane was designed with dozens of different screws, too. Then I looked at the parts manual one year and found almost all of them are spec'd as one of two types: AN526-832R8 or AN526-1032R8 truss head machine screws. The exhaust tunnel panels are oddball (coarse sheet metal screws), and the belly panel where the nose gear doors close have a small number of flush head screws. But even with those additions, that's just four types to cover every cowl, inspection panel, and belly panel screw on the whole airplane. At that year's annual, I looked closely and found every "odd" screw I'd been carefully tracking over the years was actually the wrong screw. In some cases a random screw had been improperly jammed and self-threaded into a tinnerman plate of a different size than the screw itself. In others, a speed nut that was supposed to capture the screw had been lost, and someone tried to deal with it it by jamming in the next-size-up sheet metal screw with no capture nut. In the case of riveted nut plates, I was fortunately able to clean them up with a tap. For removable and lost nut plates, I replaced them with the actual spec'd parts. It was tedious work - especially working speed nuts into tight spots - but not especially difficult. Now we have a stock of "standard" screws and nut plates in just a few sizes. Minimal hassle, and easy to replace lost or buggered screws. Worth the effort, IMO.

You're not going to get a definitive answer on this. Let's assume honorable intent by all involved. The complexity is that work on certified airplanes must be classified as a "repair", "minor alteration", or "major alteration", and that requires interpretation. A conservative mechanic might view the Tahoe vent conversion as a major alteration requiring DER review and 337 paperwork, while a liberal one might just call it a simple repair. Inbetween you have mechanics who might call the work a minor alteration based on standard practices in AC 43.13, and sign it off as such. People being human, you're going to get differences of opinion. A shade-tree mechanic on the verge of retirement is going to have a different view than a mechanic whose livelihood depends on staying out of trouble. So the question is just whose opinion matters to you. If you never sell your airplane, have an accident, or get ramp checked, then the only opinion that matters is your mechanic's (or your own, if you're an A&P). People who plan to sell their airplane someday or who worry about accident investigations and ramp checks might be more conservative about alterations. Bottom line, there's no black-and-white answer. I'm sure you can find a mechanic who will call the vent mods in this thread "illegal", but that's just one opinion, and not something worth crusading about.

If there is, I'd sure like to hear about it. When we bought our airplane, nothing in the Brittain autopilot system worked, not even the wing leveler. The first problem we found was an interior panel screw in the baggage compartment, which at some point had been installed so as to center punch a hole in one of the servo vacuum lines. :-(

Brittain themselves is the best source for these parts. Still in business, reasonably priced. Check 'em out: http://www.brittainautopilots.com/contact-us.html

Thanks for the update, Jim, even though it's bad news. At this point it's almost worth wondering if 3-D printing is the best answer. The printing part might go pretty smoothly, but I don't know the first thing about how to build a model. Maybe someone near me has a 3-D scanner that could scan the remaining good ones.

Hector, thanks for confirming I wasn't just imagining that for-sale post. Absolutely no hard feelings about you snapping them up. Do you recall if the seller got them from Plane Plastics?

Ugh, a neuron just fired. I remember now, you are correct - there is a nut on the back side. I was somehow able to get a ratcheting box wrench back there to remove the nut. Not so bad when the vent is already broken, but more precarious when trying to re-install new/newly-repaired parts. Thanks for the reminder, despite it being bad news...

Airplane is a 1976 M20F - one of the late-model Fs that's an "almost J", interior-wise. An unfortunately-timed bump of turbulence this weekend resulted in one of the partners punching his thumb right through one of the 40-year old, brittle, ABS plastic vent covers. We're pondering repair options. Seems like just last week I saw a For Sale post here, where someone was selling four of these things. Unfortunately I can't find the post now (perhaps it was taken down when a deal was made). If whoever was selling them still has them, please PM me, as we're freshly in the market. I'd at least like to know where they came from. I'm guessing Plane Plastics, though their online catalog doesn't specifically show vent covers. I refurbished the interior on our airplane about 10 years ago, including repairing some minor cracks in the vent covers. But it's been so long I can't remember the details of how to get them off for repair or replacement. My recollection is they only come out after you take down the headliner panels, and that the headliner panels won't come out without first removing all the interior side panels. I hope my recollection is poor or someone knows a trick to avoid this. Our last SB208 inspection was pretty recent, so I'd rather not have to pull every dang interior panel if it's not necessary. I don't even mind the time so much, but every R&R is just another opportunity for cracking. Tips or advice from anyone who's been through this recently are much appreciated, thanks.

It's extremely rare - bordering on never-happens territory - for an insurer to deny a claim based on trivialities such as this. Yet the myth persists. I'm sure the "risk" varies by insurer, but the aviation insurance market is a small community, and word would get around if any one insurer had draconian views. Avemco is only one of many insurers, but I find it interesting they publish details on their claim denials. Almost all denials are for reasons any reasonable person would agree are fair: e.g. unapproved pilot flying the airplane, filing a claim for an in-flight incident on a ground-only policy, etc. https://www.avemco.com/Articles/ART0006-2011.pdf Disclaimer: I haven't been an Avemco customer for many years. Not pushing them as a good choice, I just think their claim denial information is likely to be representative of the industry as a whole.

I know a little bit about the gear-up in our airplane based on a letter the owner at the time sent to the FSDO, a copy of which came with the airplane records. It was quite the fiasco. They bought the airplane with no pre-buy, and it turned out to have numerous maintenance issues. The alternator failed in flight, but they didn't notice immediately, purportedly because the low-voltage warning circuit was inop. The figured out the battery was drained when the gear stopped halfway through the extension sequence. They tried to crank it down, but the spline engage cable was maladjusted and wouldn't engage the actuator pinion gear, so they had to land with the gear partially extended. No real airframe damage, but the prop was ruined and the engine had to be overhauled due to the prop strike breaking a connecting rod. Yuck. My parts manual lists both the ITT LA11C2114 and the Dukes actuator, the latter with Mooney P/N 950158-503. But there is note regarding the Dukes that says "actuator no longer available, use LA11C2114 actuator". My guess is the Dukes actuators were still available in 1974 when your airplane was built, but not in 1976 when ours was. We had our actuator overhauled by LASAR in 2009 (they managed the process, but the work was actually outsourced to George's Electrical Service). In addition to installing new 40:1 gears, we also had the motor overhauled with new brushes, bearings, seals, etc. Total cost was $2066.82. The 40:1 gear kit itself was $1064.57 (ouch). Labor was $940.90 and the remainder was shipping and nickel/dime parts.

Only 2200 hours at time of replacement. No idea how many gear cycles over the whole lifetime, but I'd guess we did about 1 per hour in the ~400 hours we owned the airplane between 2004 and 2009 (we do a lot of 1-hour local flights). One note of interest: our airplane had a gear-up landing in 1991 (long before we bought it) with the gear partially extended. Hard to say if that put any excessive wear on the actuator gears. I'd think that would show up as acute damage to an individual tooth, which we never saw, but who knows... Sounds like your actuator is holding up better than ours did, happy for you.

Cowl is rarely cleaned, and then mostly just with water. We do have some diluted Aviation Simple Green in the hangar for degreasing/debugging. But even if one of the partners was frequently using it on the cowl, and if it was destructive, I'd think that would damage the front of the filter, not the back where it's actually worn.

Ah, is what you're calling the "sump drain" also known as the infamous "sniffle valve"? I admit my understanding of that system is fuzzy.