AndreiC

Yes, I *think* I was using Ram Air. I also suspect the LED’s used were non polarized. Do you know of a source for polarized ones?

These questions are pretty technical, and I hope someone here is more knowledgeable than me in electronics. My plane is a 1970 M20E, and I attach the schematic of the relevant dimmer circuit. 1) A while ago I replaced the lenses for the 6 indicator lights (gear up/down, hi voltage, vacuum hi/low, boost air) with nicer, new lenses. After this the lights were a bit dim, and the guy making the lenses recommended to me to replace the filament light bulbs with modern LEDs. I did this, and all was great. However, a couple of days ago I flew at night, and noticed to my surprise that even though the gear was up, both the "Gear UP" and "Gear DOWN" lights were on. The green "Gear DOWN" light was less bright, but certainly still clearly on. When I shone a light in the light sensor next to the dimmer switch only the Gear UP light stayed on. My guess is that there is a small residual current going to the Gear UP light, even though the gear is up, and only when the photoresistor is not illuminated. The original incandescent light bulb needed much more power to light up, so it was not visible, but the LED is more sensitive and senses this small current. However, I do not understand how this could be happening based on the circuitry. 2) My second question is more standard. I guess the display on my KX155 is getting old; on this last flight, when it was pitch dark, the display was mostly unreadable. I understand that the issue is that the dimming circuit lowers the voltage to the display to a level where the older display cannot light up. I read that there is a relatively easy adjustment to up the voltage slightly to the display, so that even at its lowest setting it will be readable. Does anyone know how to do this? Or have a link to a tutorial? Thanks!

As others have said, the first thing to try would be to run rich of peak in these temps (maybe 75 degrees ROP?), while also covering some part of the oil cooler with aluminum tape. If this is not enough to get your CHTs, I would get a full engine monitor and see if all my cylinders have the same problem, and proceed from there.

My own experience is simply that many times when ATC points traffic out to me (when using flight following) it takes me a while, and sometimes I never manage to spot it. Even though eye doctors say my vision is 20/20 and there's nothing wrong with my CPU afaik, I know there is a plane there but I can't spot it. I have flown several times with an air traffic controller friend who has very good eyes, and he sees traffic way more often than I do. The moral of this is that *I* feel I need every help I can get; so I use ADS-B-in as much as I can, use flight following religiously, and if any of these suggest there is a target in my direction I deviate as much as practical so as not to get anywhere close to a conflict. For me, ADS-B has been an excellent tool, as it lets me know of potential conflicts. I know it is not perfect and still scan the horizon as much as I can, but for every airplane I find by myself, ADS-B and ATC tell me of at least 10 others. So I think it is great. But I can also understand how others (with better vision, perhaps) could feel that their scan is good enough to keep them safe. I also can't forget an interview with a very experienced GA pilot who, when asked what he is afraid of the most, answered "fire on board and mid-flight collision". I know these are not as likely as many other potentially fatal accident causes, but sometimes people are not 100% logical...

I had a Cherokee 180 for 10 years and then moved to a 1970 M20E. The 180 could haul a bit more, and could be flown to more grass strips than the Mooney. It had better visibility from the cockpit (bigger windows) and felt a bit less cramped in the front (the wheel well for the nose wheel takes up some space between the front seats). The back seats were more useable in the Cherokee, though not by a lot; however, the F and J models suggested will have more room in the back as well. But after a while (took me about 4-5 months to warm up to the Mooney) I love how the Mooney flies and how efficient it is. The Cherokee was barely a 110 kt bird. The Mooney is at 145 kt on about the same amount of fuel. This means the difference between a 4 hour and a 3 hour flight to Madison-Nashville, which I do to visit my son. It also can go much higher, the 180 could barely climb above 11k, I have had the Mooney comfortably above 16k and could have kept climbing; this made a big difference for me in the mountains. But some of my feelings for the Mooney could also be a factor of the accoutrements -- the Mooney has a nice autopilot with altitude hold while the Cherokee had none, WAAS GPS, nice engine monitor... These all make quite a difference. But certainly the Mooney feels more like a traveling machine (albeit sports-car like) than a trainer.

That facebook link takes me to some guy who has not posted anything??? Was that what I was supposed to see?

PM sent

I don't know if this is ok to do in the breaking-in phase, but if this was not an issue I would try a static RPM check on the ground. Good way to see if engine makes full power. The type certificate should say what you should be seeing.

I see, sorry. As others have said, something is seriously wrong -- it should be cruising much faster. My impression was that despite the longer body, Es and Fs were very similar in speed, and I consistently see 145kts in my E without the speed mods you have. I would still do a 3-way run. It's easy: go out on a smooth day, and you fly compass headings going first straight N until the speed completely stabilizes (takes a couple of minutes; refer to the GPS ground speed, not any other speed; this will be the speed you'll record); then turn due E and read the speed after it stabilizes, and finally same thing due S. Record these three speeds and put them in the calculator here: http://www.csgnetwork.com/tasgpscalc.html It will give you your TAS.

Hold on, am I wrong? It seems that at 9500 feet your G5 shows a TAS of 156 kts, which is great!

As I said in an earlier post, I am also affected, and also with an engine rebuilt by Penn Yan (but in 2012, smack in the middle of the bad period). When I called them they were able to tell me the exact date the bushings were shipped from Lycoming to them. So I suspect they should be able to do the same for you.

Oh, so we're not talking about a Mooney? Only the original M20 (no letter) had the O320, and those should be bought only by museums -- they still have the wooden tail I think. Or maybe also some M20A's, with just the wood wing?

What engine are we talking about? Lycoming, Continental? If Lycoming, is it the IO360 (angle valve) or O360? Need more information. As an aside, for airplane engines the heads are integral to the cylinder, so you are talking about pulling the whole cylinder. It would also be very helpful to know how much the engine has been run in the past year. If the engine has sat a long time, and there is no other indication of rust (camshaft, lifters) the compressions could come back up quite a bit after running it for a while on the ground, to clear surface rust. Also, honing the cylinder and re-ringing the piston is not a very expensive affair. 1253 SMOH is not the end of engine life. If it is not making metal you are roughly 2/3 of the way to a new overhaul (2000 hours). Also could depend a lot on who did the overhaul and how much they actually did (but you said you don't know this...)

I already talked to him. His suggestion to talk to this guy in Vegas who has a business trading props yielded nothing, that is where I got the $11.5k quote.

Somehow I got this idea in my head that I should start to look into replacing the prop on my 1970 M20E. I currently have a 3 blade McCauley which is 12 years and about 550 hours old. Runs perfectly, but all my efforts to balance it well did not yield a smooth result. I was hoping to find somehow a good condition B-hub Hartzell two-blade. It does not need to be the newer scimitar, older style blades are fine. The problem is the cost. I was told by a prop shop that I could hope to get about $4k for my prop. But the same shop would only sell me a refurbished prop, and a refurbished B-hub prop will cost $11.5k. I can't justify spending $7.5k only to smooth out a bit of vibration. However, if I could find in a private transaction a good used prop for about $5k, spend another $1-2k for an IRAN, that would be within the price range that would make the proposition attractive. Where can one find listings for such items? I looked on ebay and on barnstormers. Also, here is another interesting question. Does anyone know if older style blades (non-scimitar) can be installed by a prop shop in a hub designed for scimitar blades? Or are they incompatible? How expensive is it to swap blades in a hub?

Yes, SB480F lists as possible sources of bronze the following: Connecting rod bushings Rocker bushings Crankshaft bearings Intake valve guide Piston pin plug Idler gear bushing

My reading of the SB480F is that chunks are 3/16" or greater, indeed, but chips are greater than 1/16". Their distinction seems to be into the three categories "chunks", "chips" and "small metallic particles". For example they say "Use non-metallic tweezers or a pick to sort chunks, chips, and particles that look different." Or they say "Yet metallic particles can be small dust-size particulates - that is where quantity becomes more of the issue in this case." Also Table 3 states that "1 to 9 pieces of metal (1/16 in. (1.2 mm)) diameter or less)" is fine and you should continue to operate the engine to the next scheduled oil change. So I assume such pieces are not chips.

Here is some more information after talking to live people: -- Lycoming technical support said that they agree that the AD is poorly phrased, in the sense that it appears to at the same time say that "any bronze particulates" should trigger a bushing inspection, but at the same time points you to the SB 480F which says that unless you find relatively large "chips" of bronze you can continue to monitor the situation. According to the tech person the only reason Lycoming asked the FAA to create this AD was to force people to be serious about looking at the oil filters and suction screens at each oil change (he said "you wouldn't believe how many mechanics out there do not follow these recommendations"). When asked how many engines failed due to bushings coming apart, he said he did not know. When I pressed and asked if it is more like 3 or like 300, he said he can tell me it's not 300. But, perhaps as a CYA move, he said that the way he reads the AD as phrased is that if you find even one tiny bronze particle in your oil filter, you are required to pull cylinders and check the bushings. And then, say, you fly it 50 hours, find another tiny bronze particle, you do it again. And so on. Love the FAA and their imprecise wording. -- I also talked to the final A/W inspector at Penn Yan, so a guy with a lot of experience. He said quite clearly that you should follow the guidance of the SB480F, and look for chips (>1/16" pieces) in the oil filter and suction screen. You don't find these, and maybe find a few tiny flakes, continue to operate as normal, per the SB. He also said that they did quite a few of the inspections required by the earlier 2017 AD, and only found 4-5 bushings that moved and needed to be replaced. He was not aware of any specific engines that actually failed because of moving bushings. So he was firmly recommending just watching the oil filter and the suction screen and be on your merry way. BTW, I do have the affected bushings, it was confirmed that when my engine was O/H-ed they put in Lycoming LW-13923 with a ship date of 08/2012, so smack in the middle of the affected range.

@Chaseford10 If you are ready to pull the trigger and accept the risks of buying a plane sight unseen, this may be the plane for you. Ends in 1 day, now at $56k. https://bid.gradyauctions.com/ui/auctions/128702/17417558 I was watching it as I was thinking if it sold under $50k it would be a good deal even with all the risks involved, but now it is above what I can justify as a somewhat risky flip investment. (I do have an E already.) But it does look like a good solid airplane — from what I can see in the logbooks it was flown 30-60 hours per year every year, in annual all the time, reasonable avionics, <1000 sfrm. Plus has the manual gear which is maintenance free, and no gear ups from what I can tell.

A year and a half ago I bought from Jimmy essentially the plane you want, for $85k. 1970 E with 430W and STEC 30 with alt hold, under 500 hours on engine. Interior was in bad shape, but I fixed it myself. So yes, it is possible, unless the prices have gone up a lot since then.

@N201MKTurbo: just out of idle curiosity, assuming one would want to do the bushing replacement (which I hope never to have to do, just to monitor). How many hours would you estimate it takes for an experienced engine shop to take the cylinders off, remove the connecting rods, replace the bushings, and reinstall everything? Is it something that, say, Poplar Grove could do in one full day of work (so one could fly in and out the same day), or is this a several day project? I assume the parts would add up to about $1200 (rod bolts and nuts, and all the gaskets that would have to be replaced), I am trying to estimate labor cost.

I found out more interesting information. There was a previous AD about this same exact problem, but it affected a much smaller number of engines. I am talking about AD 2017-16-11 and the relevant Lycoming Mandatory Service Bulletin (MSB) 632B. It explicitly lists a long list of engines and specific serial numbers (not even a range, specific numbers), as well as connecting rods and bushings shipped from Lycoming in a very narrow range of dates (about 1 year, sometimes between 2015 and 2017 depending on the specific rods). It also gives much more explicit procedures to test for when the bushings are bad, and how to replace bad bushings (as mentioned, this involves removing the connecting rods from the engine). What I do not understand now is what made the FAA expand the range of dates dramatically (so as now to cover a decade or more) and without specifics on what bushings were bad. According to the initial AD from 2017, there had been 5 uncontained engine failures that were attributed to bad bushings.

The summary of the Lycoming bulletin is in three steps: 1) If you don't see a certain amount of bronze in your oil filter or your oil suction screen (you need to check both at each oil change), do nothing. This can be done by a registered pilot, no need for an A&P. 2) If you do see the amount listed (quite high -- 6 bronze chips, or 3 bronze chips and 3 aluminum chips; here chip means as far as I understand it between 1/16" and 3/16"), or every time you pull a cylinder, then you need to inspect the bushing(s). This involves pulling cylinders. The two things to check are if the bushing has moved out of the rod (no longer aligned with the rod) or if it has turned in the rod. If none of these have happened, again, do nothing. 3) If you see a bad bushing, it needs to be replaced. Or you can choose to replace all four preventively in order to terminate the repetitive AD. At overhaul all bushings must be replaced. As far as I understand it, there must have been a batch of bad bushings during the period discussed, but I do not understand from the text of the AD if these were only used in the Lycoming factory and other overhaulers never saw them, or if they were in wide circulation and anyone who has had had their rods overhauled as part of a major or some other work on the rods is exposed to the risk of having one of the bad guys. The open questions, for me: a) As above, does this only apply to rods that came from the factory, or rods that had bushings installed that were provided by the factory (are there other bushing providers?), or ?? b) Is my above interpretation of the SB correct, in that you need to see a large amount of bronze to act, or is what the AD says "any amount of bronze particulate" the trigger for an inspection? c) How many engine failures were there related to this, and how come the large amounts of bronze that should have been seen in the oil filter were not caught? In other words, why should we believe it is safe to operate with a potentially bad bushing thinking we'd catch it at a 50 hour oil change?

Here is a question for the APs around here. Is it possible to replace the bushings without taking the connecting rod out of the engine? My understanding of the mechanical process involved makes me doubt it is possible, right? Then how do you replace all four bushings in 4.5 hours, per the FAA? I would think the job requires splitting the case, which is (my guess) closer to 40 hours, even without counting the cost of taking the engine off the plane and reinstalling it... I really wonder how the FAA comes up with those numbers.

After having read both the AD text and the Lycoming service bulletin it refers to, I am quite a bit more confused. Lycoming says that one has to inspect the rod bushings and worry about them if at least 6 bronze "chips" are found in the oil filter or suction screen, or at least 3 bronze chips and 3 aluminum chips are found (in which case one has to inspect the pistons as well). However, the AD text refers to the case when "any bronze metal particulates are found and the source is identified as the connecting rod bushings". According to Lycoming there is a significant distinction between bronze chips (less than 3/16" but larger than 1/16) and small dust-like pieces (smaller than 1/16"). What are we supposed to do if we find a few bronze dust-like pieces? Inspect the bushings or not?