PT20J

Legally, it’s the same thing.

I don’t think anyone knows where the fear of over square originated. 30 years or so ago I believe Kas Thomas postulated that it was a misapplication of the prohibition on radial engines to avoid operating under square. That was because low cylinder pressures can’t balance reciprocating load and the result can damage the master rod bearing. Skip

I asked Mike Busch and he pointed out that the Part 1 definition of maintenance includes inspection whereas the definition of preventive maintenance does not. Therefore, an inspection required by regulation cannot be performed as preventive maintenance (unless, in the case of an AD, it is specifically allowed as @EricJ and @M20Doc have noted). Skip

It's not about cleaning the injectors, it's about satisfying the recurrent inspection AD on the injection lines and clamps. It wouldn't be an issue if it recurred annually (because it gets checked every annual) but it recurs every 110 hours. So if I fly 115 hours between annuals, the airplane is unairworthy for the last 5 unless I bother my mechanic to stop what he's doing, look at the lines and sign the logbook. Skip

Well, to add more confusion to it, I just found the attached document which states in the Introduction that "This pamphlet provides information on authorized preventive maintenance." Later it includes a section titled Sample Checklists that are apparently items that fall under preventive maintenance. Many say "check" in a manner obviously synonymous with "inspect." One item listed is, "Check condition of fuel lines for leaks (fuel stains) and security." So, according to this pamphlet, I can check the fuel lines as preventative maintenance, and if I do preventive maintenance I have to log it, and if the preventive maintenance just so happens to satisfy an AD....??? Skip FAA P-8740-15 Maintenance Aspects of Owning Your Own Aircraft [hi-res] branded.pdf

The latest incarnation of the Lycoming fuel injection line AD 2015-19-07 requires repetitive inspections every 110 hours. FAR 1 says "Preventive Maintenance means simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations." FAR 43 App A lists an example preventive maintenance task as "Replacing prefabricated fuel lines." We know that under a FAA legal interpretation (Coleal 2009) that this list is not considered to be exhaustive, but illustrative. FAR 43.3 (g) states in pertinent part "The holder of a pilot certificate...may perform preventive maintenance on any aircraft owned or operated by that pilot..." FAR 43.9 says in pertinent part "Each person who... performs preventive maintenance ... shall make an entry in the maintenance record..." So, is there is any regulation that prevents me as a pilot owner from performing the simple inspection required by the AD and entering it in the logbook as preventive maintenance? Skip

Mooney originally used the trim piece but at some point just stopped -- probably to save a couple of bucks. Underneath it's the same. The references in the earlier 337 are interesting. Mooney doesn't list a retrofit kit for this. The part number listed is just the part number for the landing/taxi light assy from the J IPC. The wiring reference listed is a service manual section that doesn't have any wiring info at all. Skip

Avgas doesn't contain detergents like mogas to keep the injectors clean, so eventually they will develop deposits. Lycoming SI 1275C recommends cleaning "At overhaul and when engine conditions require." The Precision RSA Operation and Service Manual contains instructions on how to clean the nozzles which is recommended along with other maintenance items "during periodic inspection of the engine." Mooney's 50-Hour/100-Hr/Annual Maintenance Inspection Guide lists cleaning the nozzles. Personally, I don't mess with anything without good reason. Skip

The AD is primarily about the clamps. The problems in the field that necessitated the AD are primarily due to missing, mislocated or damaged clamps that do not properly support the fuel injector line and allow vibration to work harden the joints at the fitting attachments eventually causing a fracture. You're really better leaving the clamps alone if they are in good shape and properly located per the Lycoming SB. That's what all the mechanics I've worked with do.

The nozzles are easily removed without loosening any clamps. The clamps are not near the nozzles, there is a lot off flex in the lines and you don't have to deform or stress them. Just loosen the nut and move the lines slightly to the side. Lycoming SI 1275C "Cleaning Fuel Injector Nozzles" says to "Remove the nozzle assembly from the individual fuel lines using a wrench." It does not mention any need to remove the clamps from the lines.

I'm in the Seattle area. That would be great as I'm not having a lot of luck finding a 106A or KX 165 locally. I'll send you a PM.

Probably the best engine for even mixture distribution is a single row radial. The fuel mixture enters at the eye of a fast spinning supercharger impeller and is forced out to the cylinders through equal length intake tubes. I once tried to see how lean I could run an R-985 on a Beaver. As I pulled the mixture slowly back, it ran pretty smoothly until it just stopped. But just before it stopped, the weak mixture was burning so slowly that there was still fire in the hole when an intake valve opened and it backfired. There is no operational advantage to running too deeply LOP. LOP efficiency comes from running at lowest BSFC which is minimum and nearly constant over a fairly broad range. That's why power is a function of mixture strength LOP -- up to a point. But if you keep going leaner, the BSFC starts to increase. Looking at the BSFC curve for your engine will tell you the most efficient place to operate -- it's generally in the range of 25-50 degrees LOP. Skip

Also, keep in mind that the J cowl tends to lift up with air loads in flight. You can have perfect alignment with the spinner after you install the cowling and then after flight it can look like the engine is 1/4 to 1/2 inch low. If you are good at composite construction (I’m not — I look like a three stooges routine when I get around glue) Byron @jetdriven has a thread somewhere about how he fixed his. Skip

If you mean the Sidewinder, no. The friction roller isn’t rough enough to significantly abrade the tire. In fact, my only gripe is that it doesn’t have quite enough grip when wet. But I can still get it over the little lip into the hangar when wet with a little extra pressure. Soooo much better than doing it by hand. Skip

Wonder if anyone has seen this: #2 Nav/Com is a KX 165 connected to a GI-106A and nothing else. LOC and GS needles/flags work fine on ILS. On VOR when pulling Nav inner knob to RAD, it reads correct radial. When turning OBS to that course or radial, sometimes CDI centers with proper TO/FROM indication, but sometimes CDI remains at full scale deflection and KX 165 RAD display shows - - -. Even if CDI centers when OBS turned to proper radial, it will peg full scale when flying slightly off course. Sometimes, it appears that TO/FROM are reversed from proper sensing and CDI will not center when rotating OBS - needle just goes from full scale left to full scale right Talked to Bevan and they weren’t sure if it’s the 165 or the 106A. Talked to Midcontinent (who made the 106A for Garmin and is a Bendix King service center) and they think it’s the resolver in the 106A. I’m trying to borrow a KX 165 to swap. Anyone have any thoughts? Skip

Save yourself a lot of strain and get a Redline Sidewinder. Call Mooney and get the current Illustrated Parts Catalog and Service Manual (only available in pdf). If you plan to do any work yourself, first develop a good working relationship with an A&P (best if one with an IA). Aquire tools as needed and buy quality (not necessarily Snap on, but usually not Harbor Freight). Skip

Interesting point. For those not familiar, Vmc is the speed below which you run out of rudder authority to counteract a yaw produced by asymmetric thrust. Crossover speed is the speed below which you run out of lateral control authority to counteract a rudder hard over. Crossover speed is related to AOA in the sense that at high AOA the wing is operating at a high lift coefficient and the ability of the aileron to further increase CL to raise a wing is impaired. A roll caused by loss of an engine below Vmc in a piston twin can be counteracted by reducing power on the operating engine slightly which decreases Vmc. But, that's also really hard to do when close to the ground. Skip

I don't know; I don't recall it. I do recall the Airbus that had the vertical stab come off after a rudder hard over doublet applied by the pilot flying. But my quest was just to understand the question in terms of the definition of primary structure. The aircraft manufacturer is the final authority and Mooney says it is primary structure, so that's the answer. I think this is an excellent example of a case where there can be a lot of opinions, but only one correct answer.

Not necessarily disagreeing, but I’m curious why this would be. I believe FAA defines primary structure as structure carrying flight, ground or pressurization loads the failure of which would affect the structural integrity of the aircraft. Probably the same in Canada. Hard to see that the leading edge skin carries significant structural load. If it really matters, I’d ask Mooney. Or, maybe @M20Doc can weigh in. I’d be interested in his answer. Skip

I like my Aspen, though I've only got one tube. Do you fly instruments using it with synthetic vision? I find the pitch axis and horizon line a little indistinct for flying precisely with SV on and don't use it on approaches. Wonder if the MAX is better? Skip

I'm a "boomer" and I've been declined.

Good points, Paul. I agree that setting up two nav systems should not be overly challenging since I can do this at a low workload time. My thought is that the workload to monitor two navigation systems during a non-precision approach with no vertical guidance (I won't get LNAV+V on this) while descending close to the ground may be more workload than I might want. This is a nit perhaps, but I don't believe using the HSI bearing pointer on the VOR (it would be OK for an NDB) is what the FAA had in mind when it stated that the underlying NAVAID must be "monitored for final segment course alignment." You really need a second CDI to do that with accuracy. So now I am modifying my scan, trying to correlate two CDI indications (with the VOR perhaps scalloping a bit) while descending close to the ground. It absolutely can be done. And, if I had an operational need to do it, I would. I just think it's not the best situation. Skip

Perhaps I misunderstood the OP's question as wanting to know if GPS could be used in lieu of the VOR or NDB. There's a nuance here. While Paul correctly points out that paragraph 5 allows the use of GPS to navigate a final approach segment if the the NAVAID is operational and you monitor it for the final course alignment, the preceding paragraph 4 states that "Pilots may not substitute for the NAVAID (for example, a VOR or NDB) providing lateral guidance for the final approach segment." So to do this correctly, you have to set up and monitor two navigation systems during the final approach. That's a lot of workload and if I really needed to do it for some reason I'd have the autopilot flying the GPS and me monitoring the VOR (or NDB).

From another post... The SureFly (missing) advance curve has been bugging me, so I spoke with Jason Hutchison at SureFly. He confirmed that they removed it from the website. He said it was an oversimplification and technically incorrect. He also said that they decided for reasons he declined to elaborate on not to publish the corrected curve(s). He was pretty forthright and I didn't get the sense they are trying to hide anything. I suspect that they are tired of "experts" opining on the details of their design. OK, I get that -- I probably wouldn't get too far trying to get Subaru to send me advance curves for my Outback. Here is what I did learn: The primary design goal of the advance is to adjust timing so that the peak pressure point (PPP) is about 13 degrees ATDC which they found to be close to the Maximum Brake Torque (MBT) angle for most engines in cruise operation. Operating at MBT gives the greatest efficiency. The use of MAP and rpm is analogous to the old auto distributors that had centrifugal and vacuum advances. At 24" MAP and above, the SureFly will be at base timing. Below 21" it will be fully advanced.

Yes. As to stumbling when hot, one possibility is that there is an induction leak that gets worse as things heat up and expand. Gaskets where heads mate with risers seem to be problematic as well as the seals where risers mate with sump if not installed correctly.