Rough running IO-360

[RideOrFly]

Well, I think the shop accidentally fixed my plane. 

The IA at the shop, who hadn't been involved to this point, went through it yesterday and met with me this morning. He went through the troubleshooting guide and noted a couple of things. First off, the mixture control linkage was incorrectly installed. He would't admit that it was installed incorrectly, rather maintains that it was wrong prior to repair (when it worked perfectly) and was merely reinstalled as it was found. At any rate, he fixed it and the mixture control operates normally now. The fuel flow test demonstrated equal flow for all cylinders. Everything checked good as far as the fuel system was concerned. He rechecked the timing and found that it was good. Everything in the ignition system looked normal.

He reminded me that last week (this was after they had signed off on it and returned it to me) when I asked them to check it again, the engine ran rough and afterfired. He reminded me that at that time, the EGT on #1 was 1000-1100 (as it always has been) and that #2 and #3 were down around 600. No mention of #4. Based on this, and in spite of normal compression, he was certain that the exhaust valve on #1 was sticking. I asked if he had done any additional troubleshooting to reinforce that opinion and he said there was nothing additional to do for diagnosis. I asked if he'd done a borescope and he said he did and that the bottom of the valve looked normal. He said he hadn't taken any pictures and that he couldn't. I asked for his recommendation to remedy the issue and he again recommended pulling the cylinder and sending for OH. I asked why we wouldn't just ream it in place and he said that no one would do that because it was just too much liability to assume. I mentioned the Lycoming service instruction 1425 which prescribes and describes the procedure, but he insisted that I wouldn't be able to find anyone who would do that.

I was still not satisfied with the valve explanation so I asked that we take the QAA rep up on his offer to help troubleshoot. The IA initially refused and said he didn't need any help and that he knew what the problem was. I'm baffled that anyone would turn down free professional assistance with a problem. We finally did get him on the phone and established to my satisfaction that after the troubleshooting that was done, it was unlikely that the servo was to blame. At that point, I figured it was best to just cut my losses and proceed without the shop's help. We already had a strained relationship and it got pretty heated today, so little chance of savaging that I imagine. I helped put the cowling back on and we moved the plane outside.

I got in, and the plane started up perfectly and ran as smoothly as it ever has. I leaned it out and it ran well. I ran it rich and it ran well. I did a normal run-up and it was perfect. I did a full power run up and everything was perfect. I shut down and restarted. No problem. So it did it a few more times, ran it up a few more times and sat there enjoying the smoothness. Of note, I watched the EGTs the whole time--#1 and #4 were between 1000-1100 just as before. But today, #2 and #3 were back up to around 950. It was running so well that I'd have had no issue flying it, except it's 300 ovc and 3/4 SM vis today.

I don't know if correcting the mixture control linkage could have fixed this or if perhaps the troubleshooting dislodged some fuel obstruction in the system. I can't for the life of me figure out why they didn't run it after fixing that yesterday to see if it fixed the issue, which it apparently did. I do know that any rational person would have to make a huge leap to think that two unrelated major problems happened at exactly the same time and that fixing one would resolve the symptoms of the other. The story of a stuck valve really doesn't make sense, but I'm even less inclined to believe it when the guy telling the story isn't even aware of the manufacturer's guidance for fixing it. 

I can't thank you all enough for helping me through this, which I really, really hope is done for good. It cost me a few thousand dollars, but I feel fortunate that it didn't go any further than that. On top of the couple/few thousand more that a cylinder would have cost, I shudder to think what else they would have broken in the process.

Ultimately, this whole thing is my fault for not being more involved and informed in the first place. I want to be a pilot, not a mechanic, but I'm learning that I really don't have much choice unless I find someone I can trust.

[N201MKTurbo]

I suppose that side loads on the mixture control shaft could affect the fuel flow or allow air into the fuel flow. I know enough about that servo to be dangerous, but don't know it inside and out.

If it was extra lean, the #2 and #3 cylinders could be misfiring.

[KSMooniac]

You'll learn as you go, and will learn by hanging out here and reading everything you can.

You may have some sticky valves that are intermittent by nature, and just happen to be OK during this last episode.  Read about Lycoming "morning sickness" if you haven't already, and then find a better shop or freelance mechanic that is willing to do the wobble test and ream in place.  

[EricJ]

34 minutes ago, RideOrFly said:

Ultimately, this whole thing is my fault for not being more involved and informed in the first place. I want to be a pilot, not a mechanic, but I'm learning that I really don't have much choice unless I find someone I can trust.

Very glad to hear of a good outcome.   Sorry to hear about the issues with the shop, but that sort of thing is all too common.   Finding a good Doctor, lawyer, handyman, and mechanic are very important but often difficult tasks.  

[UteM20F]

On 1/22/2024 at 5:52 PM, RideOrFly said:

I wasn't there that day, mechanic suspected there was a problem with the magneto. It's a little overdue for IRAN, so we sent it out.

One 'good' thing out of all this, is that you had your magneto inspected, which you likely would have done in the near future anyway.  I'm glad it all worked out in the end for you!

Ute

[UteM20F]

On 1/22/2024 at 5:52 PM, RideOrFly said:

I wasn't there that day, mechanic suspected there was a problem with the magneto. It's a little overdue for IRAN, so we sent it out.

One 'good' thing out of all this, is that you had your magneto inspected, which you likely would have done in the near future anyway.  I'm glad it all worked out in the end for you!

Ute

[Shadrach]

I would run away from this mechanic. Any maintenance professional that believes that breaking the torque on through bolts to remove and re-install a jug presents less risk/liability than doing a simple “rope trick” to ream a guide, is a moron. I can’t imagine any competent mx professional holding that view.

[EricJ]

1 hour ago, Shadrach said:

I would run away from this mechanic. Any maintenance professional that believes that breaking the torque on through bolts to remove and re-install a jug presents less risk/liability than doing a simple “rope trick” to ream a guide, is a moron. I can’t imagine any competent mx professional holding that view.

You might be surprised how many do, though.    There's a lot of stuff like that (i.e., the rope trick to lap valves) that seems to be outside the skillset of many shops these days.  

[A64Pilot]

3 hours ago, EricJ said:

You might be surprised how many do, though.    There's a lot of stuff like that (i.e., the rope trick to lap valves) that seems to be outside the skillset of many shops these days.  

See, I’ll pull the jug myself. I just got through R&R’ing two on my C-85 to fix an oil leak from the push rod tubes. An hour or so I’d guess to remove and maybe two to reinstall, maybe a little longer because I’m not nearly as limber as I used to be and take breaks now when the back starts hurting, but I’d rather pull a jug than wax the airplane, it’s less work. Maybe if you had an excessively worn bottom end to start with you could spin a bearing. 

Now one of the complex twin turbo motors are I’m sure more difficult  to pull a cylinder of course. Hardest thing on a regular N/A motor is removing the baffling.

With the Jug off you can take it to an engine shop where someone who does more cylinder work in a week than I’ll do in my life can inspect the whole thing and repair anything that needs it, like if it’s been sticking, it may be burnt and either need replacing or maybe just a valve job.

I’ve yet to figure out how pulling a jug could lead to a spun bearing, much less have it happen many hours later, if you spin a bearing it will make itself immediately apparent, it doesn’t take hours. I’ve had the one bearing in an R-1340 spin, took about 30 min before I found a spot to put it down, to its credit it was still making power, oil temp was going one way when pressure was going the other.

If your paranoid about it it’s pretty easy to torque a piece of a jug in its place to maintain torque, all you need is a band saw to cut the base off of an old scrapped jug.

Do one at a time.

Lapping valves is at best a band aid, maybe if it’s just carbon you will accomplish something but if it’s honestly leaking you need to have the seat re-cut and honestly I think if you have a cylinder problem it’s best to take it to a Pro. 

I’m not saying pull a jug without troubleshooting and knowing you have a problem, just don’t be afraid to do so.

‘I think improper torque is more likely to cause a problem than the R&R, I don’t think many understand yiu need to wet torque and torque in a three step process and I maybe it’s excessive but take a lunch break or just a decent break and come back and hit everything with the final torque one last time, every once in a while I may have one move slightly, and if there are thru bolts, you have to torque both ends, shouldn’t have to but it’s possible that the stud is bound slightly and torque doesn’t pass through to the nut on the other side.

[Ragsf15e]

10 hours ago, RideOrFly said:

Well, I think the shop accidentally fixed my plane. 

The IA at the shop, who hadn't been involved to this point, went through it yesterday and met with me this morning. He went through the troubleshooting guide and noted a couple of things. First off, the mixture control linkage was incorrectly installed. He would't admit that it was installed incorrectly, rather maintains that it was wrong prior to repair (when it worked perfectly) and was merely reinstalled as it was found. At any rate, he fixed it and the mixture control operates normally now. The fuel flow test demonstrated equal flow for all cylinders. Everything checked good as far as the fuel system was concerned. He rechecked the timing and found that it was good. Everything in the ignition system looked normal.

He reminded me that last week (this was after they had signed off on it and returned it to me) when I asked them to check it again, the engine ran rough and afterfired. He reminded me that at that time, the EGT on #1 was 1000-1100 (as it always has been) and that #2 and #3 were down around 600. No mention of #4. Based on this, and in spite of normal compression, he was certain that the exhaust valve on #1 was sticking. I asked if he had done any additional troubleshooting to reinforce that opinion and he said there was nothing additional to do for diagnosis. I asked if he'd done a borescope and he said he did and that the bottom of the valve looked normal. He said he hadn't taken any pictures and that he couldn't. I asked for his recommendation to remedy the issue and he again recommended pulling the cylinder and sending for OH. I asked why we wouldn't just ream it in place and he said that no one would do that because it was just too much liability to assume. I mentioned the Lycoming service instruction 1425 which prescribes and describes the procedure, but he insisted that I wouldn't be able to find anyone who would do that.

I was still not satisfied with the valve explanation so I asked that we take the QAA rep up on his offer to help troubleshoot. The IA initially refused and said he didn't need any help and that he knew what the problem was. I'm baffled that anyone would turn down free professional assistance with a problem. We finally did get him on the phone and established to my satisfaction that after the troubleshooting that was done, it was unlikely that the servo was to blame. At that point, I figured it was best to just cut my losses and proceed without the shop's help. We already had a strained relationship and it got pretty heated today, so little chance of savaging that I imagine. I helped put the cowling back on and we moved the plane outside.

I got in, and the plane started up perfectly and ran as smoothly as it ever has. I leaned it out and it ran well. I ran it rich and it ran well. I did a normal run-up and it was perfect. I did a full power run up and everything was perfect. I shut down and restarted. No problem. So it did it a few more times, ran it up a few more times and sat there enjoying the smoothness. Of note, I watched the EGTs the whole time--#1 and #4 were between 1000-1100 just as before. But today, #2 and #3 were back up to around 950. It was running so well that I'd have had no issue flying it, except it's 300 ovc and 3/4 SM vis today.

I don't know if correcting the mixture control linkage could have fixed this or if perhaps the troubleshooting dislodged some fuel obstruction in the system. I can't for the life of me figure out why they didn't run it after fixing that yesterday to see if it fixed the issue, which it apparently did. I do know that any rational person would have to make a huge leap to think that two unrelated major problems happened at exactly the same time and that fixing one would resolve the symptoms of the other. The story of a stuck valve really doesn't make sense, but I'm even less inclined to believe it when the guy telling the story isn't even aware of the manufacturer's guidance for fixing it. 

I can't thank you all enough for helping me through this, which I really, really hope is done for good. It cost me a few thousand dollars, but I feel fortunate that it didn't go any further than that. On top of the couple/few thousand more that a cylinder would have cost, I shudder to think what else they would have broken in the process.

Ultimately, this whole thing is my fault for not being more involved and informed in the first place. I want to be a pilot, not a mechanic, but I'm learning that I really don't have much choice unless I find someone I can trust.

It’s happened to us all.  Glad your airplane seems to be running better.  I hope you can find a good shop, that’s always a bit tougher than you might think.

[Shadrach]

@RideOrFly I would urge you to be very cautious for the next few hours. Minimize time spent in phases of flight where an off airport landing is guaranteed in the event of an engine out.  Maybe log an hour or so flying circuits at altitude above the airport after some thorough ground runs.  Installing the mixture control incorrectly explains the cable issue. It seems like a long shot to attribute it to the dramatic disparity in EGTs. It might have been the cause, but right now, it’s just an unexplained correlation. 

[A64Pilot]

54 minutes ago, Shadrach said:

@RideOrFly I would urge you to be very cautious for the next few hours. Minimize time spent in phases of flight where an off airport landing is guaranteed in the event of an engine out.  Maybe log an hour or so flying circuits at altitude above the airport after some thorough ground runs.  Installing the mixture control incorrectly explains the cable issue. It seems like a long shot to attribute it to the dramatic disparity in EGTs. It might have been the cause, but right now, it’s just an unexplained correlation. 

I was going to post this but was beat to it, I was thinking that last night, be very suspicious of anything that fixes itself.

 

[RideOrFly]

10 hours ago, 1980Mooney said:

 

As @PT20J highlighted "The "rust" in the lines is suspicious."  There shouldn't be any.  And "dislodging" can't be good.

I wouldn't feel comfortable without flushing the fuel system starting with the tanks.  Perhaps this was done.

Do you know if the A&P broke connections on the fuel lines in multiple places to inspect lines?

I am not sure if you are familiar with the crash last year of that C-150 at Huntsville.  The father, (a new UAL Captain, CFII, recent experimental flight test pilot for Textron and had also been a T-6A and C-130 instructor in the Air Force) was teaching son to fly their recently purchased C-150.  Debris, in the fuel lines appears to have brought the plane down in the pattern killing both. 

Look at the pics in the very thorough Prelim in the Aviation Safety link.  It is some kind of rust looking debris that built up on the inside of the fuel lines and fittings.

Accident Cessna 150K N6059G, (aviation-safety.net)

 

I don't know specifically how/where he broke the connections. When we spoke yesterday, he told me that the original source of the "rust" appeared to be a bolt in the servo (??) that had corroded. They did not confirm that the debris was rust, just that it appeared to be. Question for anyone--if the fuel flow test was done and the fuel came out clean, that would suggest that there's no debris distal to the boost pump, correct? As far as the tanks go, I was thinking of asking the other shop on the field to drain them for me and put new fuel in. Is that a typical procedure, and I'm assuming a borescope in the tank would likely reveal any debris if it were there?

Very sad story about the 150. I'd argue that the fuel contamination brought the plane down, but a steep turn at low airspeed killed them. I try to remind myself that hitting the ground straight ahead at MCA is usually survivable, while a spin is not. But if a guy with those credentials can fall victim to that maneuvering it certainly gives me pause.

[RideOrFly]

1 hour ago, Shadrach said:

@RideOrFly I would urge you to be very cautious for the next few hours. Minimize time spent in phases of flight where an off airport landing is guaranteed in the event of an engine out.  Maybe log an hour or so flying circuits at altitude above the airport after some thorough ground runs.  Installing the mixture control incorrectly explains the cable issue. It seems like a long shot to attribute it to the dramatic disparity in EGTs. It might have been the cause, but right now, it’s just an unexplained correlation. 

 

34 minutes ago, A64Pilot said:

I was going to post this but was beat to it, I was thinking that last night, be very suspicious of anything that fixes itself.

 

I appreciate the advice. For sure, the first flight is going to be at least a couple of hours circling the field at 3000 or so. One of our runways has better off field opportunites than the other, so I'll make sure it's a day I can take off on that one. 

[Shadrach]

4 hours ago, RideOrFly said:

As far as the tanks go, I was thinking of asking the other shop on the field to drain them for me and put new fuel in. Is that a typical procedure, and I'm assuming a borescope in the tank would likely reveal any debris…

If the fuel is clear at the sumps and the gascolator screen is clean, there is little reason to drain the tanks.

[Shadrach]

12 hours ago, A64Pilot said:

See, I’ll pull the jug myself. I just got through R&R’ing two on my C-85 to fix an oil leak from the push rod tubes. An hour or so I’d guess to remove and maybe two to reinstall, maybe a little longer because I’m not nearly as limber as I used to be and take breaks now when the back starts hurting, but I’d rather pull a jug than wax the airplane, it’s less work. Maybe if you had an excessively worn bottom end to start with you could spin a bearing. 

Now one of the complex twin turbo motors are I’m sure more difficult  to pull a cylinder of course. Hardest thing on a regular N/A motor is removing the baffling.

With the Jug off you can take it to an engine shop where someone who does more cylinder work in a week than I’ll do in my life can inspect the whole thing and repair anything that needs it, like if it’s been sticking, it may be burnt and either need replacing or maybe just a valve job.

I’ve yet to figure out how pulling a jug could lead to a spun bearing, much less have it happen many hours later, if you spin a bearing it will make itself immediately apparent, it doesn’t take hours. I’ve had the one bearing in an R-1340 spin, took about 30 min before I found a spot to put it down, to its credit it was still making power, oil temp was going one way when pressure was going the other.

If your paranoid about it it’s pretty easy to torque a piece of a jug in its place to maintain torque, all you need is a band saw to cut the base off of an old scrapped jug.

Do one at a time.

Lapping valves is at best a band aid, maybe if it’s just carbon you will accomplish something but if it’s honestly leaking you need to have the seat re-cut and honestly I think if you have a cylinder problem it’s best to take it to a Pro. 

I’m not saying pull a jug without troubleshooting and knowing you have a problem, just don’t be afraid to do so.

‘I think improper torque is more likely to cause a problem than the R&R, I don’t think many understand yiu need to wet torque and torque in a three step process and I maybe it’s excessive but take a lunch break or just a decent break and come back and hit everything with the final torque one last time, every once in a while I may have one move slightly, and if there are thru bolts, you have to torque both ends, shouldn’t have to but it’s possible that the stud is bound slightly and torque doesn’t pass through to the nut on the other side.

I don’t think it’s paranoia. From what I’ve read, there is a measurable increase in bottom end issues in engines that have had cylinders removed. 

The article below has some interesting opinions of both Mike Busch and an experienced DER.

I would not be opposed to it if there was a good reason. It would take a hell of an oil leak to qualify as a good reason.

https://www.aopa.org/news-and-media/all-news/2020/march/pilot/savvy-maintenance-risky-business

[EricJ]

4 hours ago, RideOrFly said:

I don't know specifically how/where he broke the connections. When we spoke yesterday, he told me that the original source of the "rust" appeared to be a bolt in the servo (??) that had corroded. They did not confirm that the debris was rust, just that it appeared to be. Question for anyone--if the fuel flow test was done and the fuel came out clean, that would suggest that there's no debris distal to the boost pump, correct? As far as the tanks go, I was thinking of asking the other shop on the field to drain them for me and put new fuel in. Is that a typical procedure, and I'm assuming a borescope in the tank would likely reveal any debris if it were there?

Very sad story about the 150. I'd argue that the fuel contamination brought the plane down, but a steep turn at low airspeed killed them. I try to remind myself that hitting the ground straight ahead at MCA is usually survivable, while a spin is not. But if a guy with those credentials can fall victim to that maneuvering it certainly gives me pause.

I'll +1 that I wouldn't worry too much about debris in the tank or otherwise for a while, especially if your sump and gascolator samples are clean.    If/when you are so inclined or there is an opportunity to look at it, your electric boost pump is just forward of the gascolator and just aft of the left cowl flap.   That cover comes off (typically during annual or similar inspection) and you'll be able to see whether you have the additional fuel filter attached to the output end of the pump.   I'd guess you probably do have one, as it seems that most J models do.   Mine does.    Any crap in the tank has to go through that filter AND the finger filter in the servo before it gets to the servo innards or any further than that.    Both of those filters have very fine filtration properties, so not much other than liquid fuel gets past them.    Since your servo was just rebuilt, the finger filter will be clean and able to do its job with no issues.

Since the finger filter is the first thing the fuel encounters when it gets to the servo, any crud in there won't come from any bolts corroding in the servo.    When my airplane had similar issues, the finger filter was full of rusty crud, but it had lived outside in the Nevada desert for the previous twenty years and had all kinds of water infiltration issues due to poor maintenance of fuel cap o-rings, etc.   With a fresh servo you should be in good shape for a while, but if you have the additional filter at the boost pump it'll be worth checking that at the next inspection (which is supposed to happen, anyway).

[PT20J]

One think to note is that the servo finger screen is supposed to be removed for inspection and cleaning from the side where the fuel line attaches to prevent any crud from falling out of the screen and into the servo. It can be removed from the other side, but that isn't the right way to do it and risks contaminating the servo if there is crud in the filter.

[A64Pilot]

4 hours ago, Shadrach said:

I don’t think it’s paranoia. From what I’ve read, there is a measurable increase in bottom end issues in engines that have had cylinders removed. 

The article below has some interesting opinions of both Mike Busch and an experienced DER.

I would not be opposed to it if there was a good reason. It would take a hell of an oil leak to qualify as a good reason.

https://www.aopa.org/news-and-media/all-news/2020/march/pilot/savvy-maintenance-risky-business

I’ve read it and while I used to doubt it, reading threads like this one had me wondering, like the one where the A&P wanted to lean the carb out for missing.

It makes me sort of realize that anything’s possible.

The C-85 has two rubber cups that seal with spring rings to the case and to the push rod tubes. The push rod tubes are swaged into the heads, you can’t remove the tubes, only can remove the cylinders to replace these rubber cups. Being rubber when they get old they leak, and yes it was a bad leak, been leaking for years but over time got pretty bad as leaks don’t get better.

There is an STC to install “improved” push rod tubes from the big later model engines that can be removed without pulling the cylinders but it’s of course hundreds of $$$ and it’s not worth it to me.

Interestingly on the older C as in C-65,75, 85 90 Continental engines there are no thru studs that go to the cylinders, they screw into the opposite case but do not go all the way through. The O-200 does I believe have thru studs as does new C-85 cases. I think thru studs are easier to manufacture, but probably stronger too as the C engines will sometimes pull a chunk out of the case from those studs most likely associated with a prop strike.

But if you think about it removal of the jugs can’t be what causes bottom end problems, it had to be improper torque, as in not torqueing both sides of  thru studs, most likely because it’s often a lot more work as usually baffling has to be removed to torque the opposite side.

The cure in my opinion is proper procedures, just like Mags falling off and who knows how many other things. Maintenance induced failures are real, but it’s not from maintenance, it’s from improper procedures.

Cylinders are R&R’d on piston aircraft it seems almost as often as brakes are re-lined or tires changed, Lord knows how many per year are done, yet the failures are rare.

I’m the guy who doesn’t like patches, I fully understand a temp repair to get home though.

To use an Auto example because I think most understand that, but if I blow a radiator hose, I don’t replace it and drive on, because I bet I’ll be replacing the other hose or the thermostat or the heater hoses soon and breaking down several times is often why people talk themselves into believing they need a new car, when all they needed was proper maintenance. I replace all of that but stop short of the water pump and flush the radiator too.

I’m a huge believer in Preventative Maintenance, but many are being sold on don’t touch it until it breaks maintenance. I think you can run that way for awhile, but what you’re doing is setting yourself up for a never ending string of unscheduled maintenance.  Because as the man said in one of the better commercials. “Pay me now or pay me later”.

So it’s my opinion that by removing and inspecting a Jug that that has a sticking valve and correcting any deficiencies that cylinder has means it’s going to be a long time before I have anymore problems with it.

Its my understanding that the better engine shops regularly take brand new, zero time cylinders and send them off for a proper three angle valve job and the guides precision honed, not reamed because you can’t get the fine finish and straight walls etc with a reamer, especially by hand reaming. In fact I believe that loose clearances is very often why they stick, the loose clearances allow the oil to coke into carbon, that reduces the clearances to zero and they stick, just like a ring can, usually rings stick in worn cylinders not tight ones.

One day I’m going to the machine shop that does this guide honing because I’ve not seen that. I hadn’t even heard of it before speaking to Carlos Gann

[Mac80]

After my engine had an extensive IRAN I had engine installed and dual magneto overhauled and put back on the engine. 
When the dual magneto was set it was set to a different engine so it was not firing correctly for my IO360. 
It was hard to start and missed and I knew something was not right. Changing the setting corrected the timing problem.

[Will.iam]

On 1/25/2024 at 6:46 AM, RideOrFly said:

I don't know specifically how/where he broke the connections. When we spoke yesterday, he told me that the original source of the "rust" appeared to be a bolt in the servo (??) that had corroded. They did not confirm that the debris was rust, just that it appeared to be. Question for anyone--if the fuel flow test was done and the fuel came out clean, that would suggest that there's no debris distal to the boost pump, correct? As far as the tanks go, I was thinking of asking the other shop on the field to drain them for me and put new fuel in. Is that a typical procedure, and I'm assuming a borescope in the tank would likely reveal any debris if it were there?

Very sad story about the 150. I'd argue that the fuel contamination brought the plane down, but a steep turn at low airspeed killed them. I try to remind myself that hitting the ground straight ahead at MCA is usually survivable, while a spin is not. But if a guy with those credentials can fall victim to that maneuvering it certainly gives me pause.

Here is the sad reality, there have been more than a few captains that i see that turn on the autopilot as soon as the gear is up and disconnect the autopilot below a 1000 ft agl to land. Getting at most less than a minute of hand flying time and that is with auto-thrust which is going to keep you from getting too slow. With a 6-month sim check. They are current but not proficient IMO. Now to take that same rusted skillset into a small light GA aircraft where a loss of thrust results in a rapid slow down compared to the inertia of a big jet can happen faster than the rust can be removed from the skillset let alone the reaction time needed to identify what the correct action should be at that moment can be over whelming. Add to that the low altitude time compression of losing those few ft available can be lethal.

[RideOrFly]

Went out to the airport for a little while this afternoon. I've always given the wings a little shake at the start of the preflight. Today, I shook the crap out of them a couple of times and then bounced the tail up and down a bit. This was the first sample from the right tank. Left tank had no water at all and the gascolater sample was clean as well (taking off on the left tank for the foreseeable future). I took the right fuel cap apart and the inner o-ring does look a bit worn. I recently ordered replacements so will plan to fix that. Any ideas why the water is so dirty? 

[EricJ]

When I've had water in the fuel it often looks like that.

[Shadrach]

I have never gotten that much water out of a Mooney tank though I know it can happen. Any time that I’ve gotten water out of a tank it’s clear. That looks like it’s been in there quite a while. I suspect that some or all the rib holes on the tank bottom are covered (sealant). The rib holes at the top of the tank may be blocked as well. If they are it will be very difficult to fill the tanks to capacity.

[RideOrFly]

2 minutes ago, Shadrach said:

I have never gotten that much water out of a Mooney tank though I know it can happen. Any time that I’ve gotten water out of a tank it’s clear. That looks like it’s been in there quite a while. I suspect that some or all the rib holes on the tank bottom are covered (sealant). The rib holes at the top of the tank may be blocked as well. If they are it will be very difficult to fill the tanks to capacity.

One of the only issues during the prebuy was that there were drain holes that were not open. It actually delayed delivery a couple of weeks while the issue was addressed. I assume that the work was completed adequately/in accordance with the SB, but will see if I can get a better look in there once the fuel level is down some. I've never had any trouble getting it completely full.