Another emergency in the books

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Alexb2000

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Alexb2000
As some of you know my 206 has been in the shop getting an annual and what turned out to be a top overhaul. Anyway the aircraft was done the end of last week and I needed to fly an extended cylinder breakin flight of about 2 hours. So after doing a triple pre-flight, 45 minute ground hold for departure, I left KADS at 9:30 this morning. Anyway, on the climb out over Love the engine starts running rough with what sounds like a miss. Looking at the engine monitor #2 has gone very hot relative to the other cylinders. So anyway declare and turn back. LOTS of traffic I'm right in the Love field landing corridor. Anyway, I reduced power immediately because if it seized I didn't want to be at high power and possibly tear the engine from the mount or other bad things. Anyway, I had enough altitude, brought it in high, and back to the shop for a cuss and discuss. The wife handled the cussing part with the service manager pretty well. So what could cause one cylinder to do that? Clogged injector?
 
Too much gold plating on the valves.

An SB for valve removal and inspection will be issued for said improperly manufactured valves...
 
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Sticking valve, clogged injector, bad ignition. Clogged injector/crud in the injector pressurization lines is my #1 guess. Make sure they borescope that cylinder. I've seen an AJ1A melt a piston like butter due to detonation.

Unfortunately, crud in the injector pressurization isn't uncommon, but it is a real pain. This is one of the general problems with turbo engines and the extra components/complexity.

Glad you're alright.
 
"Very hot" without a number is hard to pin down, but I'd look at metal to metal contact with piston/ring and cyl. Gonna need a borescope. Could be other stuff too, but for 'very hot' I would look at large metal mass problems.
 
With a 45 minute ground hold, probably just a fouled plug. With one plug gummed up, the EGT will rise. Usually it is the bottom plug.
 
John Collins said:
With a 45 minute ground hold, probably just a fouled plug. With one plug gummed up, the EGT will rise. Usually it is the bottom plug.
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That's what I was thinking. Did you lean on the ground before takeoff?
 
I always lean extensively for ground ops. I've flown these engines lots of hours in three aircraft and never fouled a plug.

However, it started me thinking about the possibility of excessive break in lube in the cylinder? It did run prefect during the mechanics run in and during the ground hold though. Seems like if it was fouled I would have seen the signs earlier.
 
Alexb2000 said:
I always lean extensively for ground ops. I've flown these engines lots of hours in three aircraft and never fouled a plug.

However, it started me thinking about the possibility of excessive break in lube in the cylinder? It did run prefect during the mechanics run in and during the ground hold though. Seems like if it was fouled I would have seen the signs earlier.
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Pull the plugs and take a look? :dunno:
 
Ted DuPuis said:
Sticking valve, clogged injector, bad ignition. Clogged injector/crud in the injector pressurization lines is my #1 guess. Make sure they borescope that cylinder. I've seen an AJ1A melt a piston like butter due to detonation.

Unfortunately, crud in the injector pressurization isn't uncommon, but it is a real pain. This is one of the general problems with turbo engines and the extra components/complexity.

Glad you're alright.
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Thanks. When this one was almost new I had bits of fuel hose clog a few injectors (also on departure). Acted just like this but even worse.

I will ask them to borescope and compression test to see if any damage was done.

Weird thing about emergencies the more you have the better you handle them. Seems contrary to everything you hear on these boards.
 
Alexb2000 said:
Weird thing about emergencies the more you have the better you handle them. Seems contrary to everything you hear on these boards.
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There's a lot to that. I expected things to go wrong in the Aztec and Navajo, that was good training.
 
What engine?

For all that work and time down Id hope ya came out of it with a 550 and black Mac prop.
 
A ground run for 45 minutes is detrimental to brand new cylinders. High friction and little cooling. What was the #2 CHT during your 45 minute wait?
It's after the fact but you should have waited till there was less traffic even if it was very early or very late in the day.
 
Let the woman do the cussing instead of you? Way to go, she-man.
 
RichNY said:
A ground run for 45 minutes is detrimental to brand new cylinders. High friction and little cooling. What was the #2 CHT during your 45 minute wait?
It's after the fact but you should have waited till there was less traffic even if it was very early or very late in the day.
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I've never heard this. It was about 50F. No cylinder showed above 245ish on the ground. I agree though it wasn't ideal.
 
Ted DuPuis said:
TIO-540-AJ1A
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Ahhh, newer 206, bummer.

Never got why people buy those things, made a living partially in a 550ed U206, always behaved for me, and those 550s are great engines if flown right.
 
Alex, check page 6 on ECI's website for breaking in cylinders. The bold print about overheating the barrel while CHTs remain OK during a long ground run is interesting.
 
James331 said:
Ahhh, newer 206, bummer.

Never got why people buy those things, made a living partially in a 550ed U206, always behaved for me, and those 550s are great engines if flown right.
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I never understand why some people have to be anonymous loud mouth know it all's, but here you go. Since you've got it all figured out, why don't you post up your plane and let us take a look? Further, why don't you come out of the shadows and take credit for all these pearls of wisdom? I'd really like to get together and talk about this face to face, it's been one of those days. Seriously, take it somewhere else, I was actually looking for some advice here, not a "your plane is crap" comment.
 
Ted DuPuis said:
Sticking valve, clogged injector, bad ignition. Clogged injector/crud in the injector pressurization lines is my #1 guess. Make sure they borescope that cylinder. I've seen an AJ1A melt a piston like butter due to detonation.

Unfortunately, crud in the injector pressurization isn't uncommon, but it is a real pain. This is one of the general problems with turbo engines and the extra components/complexity.

Glad you're alright.
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I just talked to the shop, you're right again. There was a piece of trash in the injectors. No one knows where it came from, but there you go. Good news is no damage, borescope and compression good, so just one of those things. Second time this has happened and it only seems to come out after a full power run, not during any kind of low power ops.

RichNY said:
Alex, check page 6 on ECI's website for breaking in cylinders. The bold print about overheating the barrel while CHTs remain OK during a long ground run is interesting.
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I'll check it out, thanks. I just don't know what you can do about it at a busy airport.
 
The times I've had partially blocked nozzle on the TIO540 in the Mirage it felt like the engine was going to fail. As the power came down for landing it smoothed out dramatically. Many times I would find black rubber particles in the nozzle that came from the short reference air hoses that is connected to each fuel nozzle.
 
John Collins said:
With a 45 minute ground hold, probably just a fouled plug. With one plug gummed up, the EGT will rise. Usually it is the bottom plug.
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For my clarification; does a fouled plug, say from an extended ground run, result in a high EGT or a low EGT?

I had a bottom plug foul during a conga line wait at Oshkosh this year and I what I recall is that the EGT went cold. Which is the opposite of what I would expect since I would think unburned fuel would still be burning late in the cycle and boosting EGTs.

But maybe I'm remembering that the CHT fell....
 
kmead said:
The times I've had partially blocked nozzle on the TIO540 in the Mirage it felt like the engine was going to fail. As the power came down for landing it smoothed out dramatically. Many times I would find black rubber particles in the nozzle that came from the short reference air hoses that is connected to each fuel nozzle.
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Thanks Kevin. Exactly what happened to me when the plane was almost new and now this. Same symptoms as you mentioned both times. Is the ferrel on the hard lines that go into the rubber hoses sharp? Seems like they may be shaving off little chunks if they are not put on carefully.
 
Alexb2000 said:
I just talked to the shop, you're right again. There was a piece of trash in the injectors. No one knows where it came from, but there you go. Good news is no damage, borescope and compression good, so just one of those things. Second time this has happened and it only seems to come out after a full power run, not during any kind of low power ops.
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Glad my prediction was right since it was simple. :)

When the system gets apart, it's just something that happens. Those little rubber hoses are junk and seem to do that regularly. You'll only notice it when the power gets up because that's where fuel really matters, plus it can take a bit for the rubber to lodge in place.

Incidentally, this is one of the turbo complexities I just don't like. I've seen this happen a lot.
 
Ted DuPuis said:
Glad my prediction was right since it was simple. :)

When the system gets apart, it's just something that happens. Those little rubber hoses are junk and seem to do that regularly. You'll only notice it when the power gets up because that's where fuel really matters, plus it can take a bit for the rubber to lodge in place.

Incidentally, this is one of the turbo complexities I just don't like. I've seen this happen a lot.
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This seems like an easy fix? Do they make better hoses?
 
Jay Honeck said:
This seems like an easy fix? Do they make better hoses?
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Keep in mind that the hoses are given a pretty harsh environment. 150+ MPH air while operating, and then 400F+ temperatures after engine shutdown. So yes, there are better hoses that exist, but they'll get old and brittle after a while as well.

Really, a better solution with turbos is ditching the need for pressurizing the fuel injectors with extra air. This is where electronic fuel injection/FADEC is a big plus.

But even then, wastegate controllers, the turbos themselves, inconel exhausts, etc. are all points of extra complexity, expense, and failure modes that have made me shy away from wanting a turbocharged plane.
 
Ted DuPuis said:
But even then, wastegate controllers, the turbos themselves, inconel exhausts, etc. are all points of extra complexity, expense, and failure modes that have made me shy away from wanting a turbocharged plane.
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Me, too.

Well, and it helps that I've never lived more than 650' above sea level. :)
 
Jay Honeck said:
Well, and it helps that I've never lived more than 650' above sea level. :)
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Yeah, out west you definitely get more advantages with turbos vs. us flatlanders. Although I'd be more inclined to go with a bigger naturally aspirated engine (and high compression if experimental) than turbos, just back to the complexity issue. That is, unless I decided I needed pressurization, at which point they become a necessary evil.
 
A Piper distributor would replace the ref. air hoses every year, they must of had a bad experience. I still think that's going overboard but I do replace them anytime the nozzles are removed. The GAMI nozzles don't have the removable Venturi and can be a bit tough to find and remove the rubber chunks from the air side of the nozzle.

I wish the symptoms would present on the maintenance run instead of upon delivery to the owner. The hoses are cheap for Lycoming parts.
 
Well after reading that I'd be inclined to replace those hoses every year too. :eek:
 
narchee said:
Well after reading that I'd be inclined to replace those hoses every year too. :eek:
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Don't forget that when you do replace the hoses, you have the risk of getting junk in the injectors. More MX is not always better.
 
So the FSDO called me today about what happened. I know a lot of you are anti-FAA, but my experience couldn't have been more constructive. We talked about what happened, the recent maintenance, where and by whom, etc. All things you would want to discuss if you were investigating an incident. Of course the next step is to find out from Cessna and Lycoming if there is something systemically wrong in the fuel system that could lead to these kinds of emergencies. We'll see what happens.
 
Glad you got it back on the ground OK Alex. Am not familiar with your area, but at my uncontrolled I fly 1000 above highest TPA or in the pattern after mechanic work until comfortable.

My buddy at the Class C got permission to fly a "high pattern" working off his first hours in their RV-8 project.

My area doesn't have all the trees your area does either. Makes things interesting after annual in your area:eek:
 
danhagan said:
Glad you got it back on the ground OK Alex. Am not familiar with your area, but at my uncontrolled I fly 1000 above highest TPA or in the pattern after mechanic work until comfortable.

My buddy at the Class C got permission to fly a "high pattern" working off his first hours in their RV-8 project.

My area doesn't have all the trees your area does either. Makes things interesting after annual in your area:eek:
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Thanks. KADS (Addison, TX) is tough because the airport is under a shelf of the DFW Bravo and just North of Dallas Love Field. It really isn't a good place to do a post maintenance flight because you can't really loiter very well anywhere close. I asked for a couple of turns in the pattern, but they couldn't accommodate me until later in the day because there was a lot of traffic coming and going. That's why the ground ops took 45min alone. That said I agree that your approach is generally the best.

I did finally complete the maintenance flight yesterday. I flew 15min to the North over some open areas and near a good airport and just turned circles for a couple of hours.
 
Alexb2000 said:
I did finally complete the maintenance flight yesterday. I flew 15min to the North over some open areas and near a good airport and just turned circles for a couple of hours.
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Good that you got it completed and in a relatively safe area. I've had several "deals" with most right after maintenance.
 
Ted DuPuis said:
Yeah, out west you definitely get more advantages with turbos vs. us flatlanders. Although I'd be more inclined to go with a bigger naturally aspirated engine (and high compression if experimental) than turbos, just back to the complexity issue. That is, unless I decided I needed pressurization, at which point they become a necessary evil.
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I like the way this Ted guy thinks.....:yes::yes::yes:.:)....:D
 
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