Acclaim Turbo Toast...?

[Mooneymuscle56m]

Hello Mooney folks

I just got this attached video from my MSC.  The plane had no symptoms of any loss of power.  I was told 1000 hours is normal life, I have 1340. I fly LOP most of the time 2200/27.5-28.5ins.   Was told $3k each is worst case scenario.

i regularly change oil with Aeroshell 15-50 every 25-35 hours and have never done a turbo cool down.  I found it just heats up everything. 
 

Any Acclaim folks have Turbo experiences to share? 
 

[Vno]

Impressive that that held together. Serious play in that.

I had a RayJay turbo casing break so I had to replace it. I used Main Turbo in CA. Very pleased with it. Price for that turbo O/H exchange was around $3K.

He didn't tell me a normal amount of hours that they last. That 1000 number is interesting info.

Brian

[Geoff]

Sorry to hear about the bad news.  I moved from a 231 to an Acclaim a year ago.  I learned from flying the 231 for 8 years to ALWAYS wiggle the exhaust pipes to check for loose turbo components preflight.  The 231 only had one turbo and it dumped directly to the exhaust.  I still do this although with the 2 turbos and the crossover exhaust I'm not sure its as useful as it was on the 231.

In 8 years ~100 hours a year flying the 231 I rebuilt the turbo once, so ~1,000 hours of mean time before failure is probably not a bad outcome at 1340 hours.  Its comforting to have a good MSC go over the aircraft.

Good luck with the repair.

[alextstone]

I would wager that has been developing for far longer than 25 hours flight time....which begs the question:  Why wasn't it identified at a previous oil change?

[Mooneymuscle56m]

46 minutes ago, Vno said:

Impressive that that held together. Serious play in that.

I had a RayJay turbo casing break so I had to replace it. I used Main Turbo in CA. Very pleased with it. Price for that turbo O/H exchange was around $3K.

He didn't tell me a normal amount of hours that they last. That 1000 number is interesting info.

Brian

They sent it off to Main Turbo.  

[aviatoreb]

I love the folks at Main Turbo - they are the best.  They have a very cool and unique test rig where they will spin up the overhauled turbo and test it for harmonics when they are done.  

I found out the scary way that 1000hr to failure is a standard mean time to failure in turbos - I figured that out be having a turbo failure in flight.  Happily - simply a learning day for me with a good outcome this time.

[Mooneymuscle56m]

25 minutes ago, alextstone said:

I would wager that has been developing for far longer than 25 hours flight time....which begs the question:  Why wasn't it identified at a previous oil change?

That would have been yours truly.  I have found broken egt probe clamps, I never thought to wiggle the turbos.  I will be adding that. 

Edited August 7, 2020 by Mooneymuscle56m

[alextstone]

Just now, Mooneymuscle56m said:

That would have been yours truly.  I found broken egt probe clamps, I never thought to wiggle the turbos.  I will be adding that. 

 I hope my comment was not offensive. That just looks like it could have been disastrous.   The heat signature from the leaking exhaust may have been a good early warning sign as well...

[ArtVandelay]

That would have been yours truly.  I found broken egt probe clamps, I never thought to wiggle the turbos.  I will be adding that. 

You can see the stains on the casing of the turbo.

[jlunseth]

1 hour ago, Geoff said:

Sorry to hear about the bad news.  I moved from a 231 to an Acclaim a year ago.  I learned from flying the 231 for 8 years to ALWAYS wiggle the exhaust pipes to check for loose turbo components preflight.  The 231 only had one turbo and it dumped directly to the exhaust.  I still do this although with the 2 turbos and the crossover exhaust I'm not sure its as useful as it was on the 231.

In 8 years ~100 hours a year flying the 231 I rebuilt the turbo once, so ~1,000 hours of mean time before failure is probably not a bad outcome at 1340 hours.  Its comforting to have a good MSC go over the aircraft.

Good luck with the repair.

Me too. I don’t wiggle it hard, just push it enough to see if it will move. Would not want the clamp coming off in flight. Also, every once in awhile do a proctological exam on the exhaust, put your finger in it, rub it around, and check to see if the grime is dry or oily. Dry is good, oily is bad. Lastly, watch for discoloration on the outside. Not necessarily easy to tell the difference between heat discoloration, which is normal, and leakage, which is not, but if there is leakage there will usually be a fine gray or whitish powder.

That’s why there is an inspection door, at least in the 231 there is.

Edited August 7, 2020 by jlunseth

[kortopates]

Wow - all I can say is how lucky you are before things got much worse. More than likely, the next thing that would have happened in flight, and more likely or sooner at a higher altitude flights where its spinning faster, that the loose bearing housing would have been pumping more and more oil out the exhaust. You might have even noticed that oil consumption had already been higher on some flights as opposed to others, with the higher flights burning more oil and lower flights being normal.  

When things started to fail, would the pilot have noticed the oil pressure declining in flight as the oil pump started cavitating from lack of oil, i.e. dropping out of the green and into yellow? If not the seizing turbo and loss of power would  certainly alert the pilot. Such things were not that far off in the future if this was left unchecked!

So glad it got discovered while you were safely on the ground and this is just a great learning experience rather than unnecessary test of finding an airport to land now! 

Thanks for sharing

BTW, everything your MSC said is spot on, I'd expect mid-time TBO life on the turbo. Some only go 800 hrs some go even longer than your 1300 but that is great. It also sounds like you were running it pretty gentle at a low LOP power mostly. May I ask what your cruising TIT was? This had nothing to do with turbo cool downs. But I assume you weren't operating the turbo as new owner till late in its life, so the question about TIT is really for how it was operated before you bought it and I would suspect it was very near max TIT at high power.

Incidentally, inspecting involves touching and wiggling virtually everything on the aircraft that we want to verify the security and integrity of which includes  every hose and every component that could get loose. Exhaust leaks sure help to draw our attention in.

[kortopates]

BTW, since we have all different types of Turbo owners here, as most realize this incident  has nothing special about it from being an Acclaim, all of us that fly a Turbo from the STC'd Vintage Mooneys, to the TCM TSIO-xxx and Lycoming TIO-xxx, we all have the same exposure to these kinds of issue to be on the lookout for. It doesn't matter what engine or airframe, a Turbo is a Turbo!

[carusoam]

Turbo health is everything...

• Some engines are a real challenge to get restarted after a turbo failure in the FLs...
• Exhaust leaks on the high pressure side can melt and cut things under the cowl...
• CO may start entering the cabin...

Do you have a CO monitor?

Wondering if you were seeing any elevated CO readings to give a hint of the turbo’s declining health...

PP thoughts only, not a mechanic...

Best regards,

-a-

[aviatoreb]

I recently saw some slightly elevated CO monitoring which then sent me (us - the mechanics) chasing for induction leaks.  We did find a number of small induction leaks and likewise we bought a complete set of new gaskets from Main turbo.  Hurray for instrumentation.  None of the leaks was large enough to see, or even to find with a soap test with the engine running due to the wind of the prop - but they did show themselves when pressurizing the system with the engine off.  Enough  numerous small leaks to register on the CO monitor.

[jlunseth]

George Braley tells a great story about his brother, who was piloting a turbo twin of some kind, a Piper I think. He noticed odd readings on the engine monitor (don’t remember what they were), made an emergency descent and I believe he put it down in a field with his family on board. The NTSB inspector came out and talked to him. Said he was glad to be able to speak to him. George’s brother was apologetic about the off field. The inspector said no, you don’t undertand, this is the fourth one of these failures I have investigated on this model aircraft and you are the first pilot I have been able to talk to. Great job!

[Mooneymuscle56m]

1 hour ago, ArtVandelay said:

You can see the stains on the casing of the turbo.

I have noticed the discolor, It has been discolored since I have owned it, 3 years 310 hours.  I figured it was due to the extremely temperature it takes.

[Mooneymuscle56m]

1 hour ago, kortopates said:

Wow - all I can say is how lucky you are before things got much worse. More than likely, the next thing that would have happened in flight, and more likely or sooner at a higher altitude flights where its spinning faster, that the loose bearing housing would have been pumping more and more oil out the exhaust. You might have even noticed that oil consumption had already been higher on some flights as opposed to others, with the higher flights burning more oil and lower flights being normal.  

When things started to fail, would the pilot have noticed the oil pressure declining in flight as the oil pump started cavitating from lack of oil, i.e. dropping out of the green and into yellow? If not the seizing turbo and loss of power would  certainly alert the pilot. Such things were not that far off in the future if this was left unchecked!

So glad it got discovered while you were safely on the ground and this is just a great learning experience rather than unnecessary test of finding an airport to land now! 

Thanks for sharing

BTW, everything your MSC said is spot on, I'd expect mid-time TBO life on the turbo. Some only go 800 hrs some go even longer than your 1300 but that is great. It also sounds like you were running it pretty gentle at a low LOP power mostly. May I ask what your cruising TIT was? This had nothing to do with turbo cool downs. But I assume you weren't operating the turbo as new owner till late in its life, so the question about TIT is really for how it was operated before you bought it and I would suspect it was very near max TIT at high power.

Incidentally, inspecting involves touching and wiggling virtually everything on the aircraft that we want to verify the security and integrity of which includes  every hose and every component that could get loose. Exhaust leaks sure help to draw our attention in.

Yes I am very fortunate and thankful it was discovered.  My normal flight could take me 20-30 mins to get it on the ground if it came apart or started a fire.  
 

It just reminds me the kind of trust we put in our mechanics and our equipment.  Liability assumed by these shops is staggering. Workmanship is life or death. 

[Mooneymuscle56m]

47 minutes ago, carusoam said:

Turbo health is everything...

• Some engines are a real challenge to get restarted after a turbo failure in the FLs...
• Exhaust leaks on the high pressure side can melt and cut things under the cowl...
• CO may start entering the cabin...

Do you have a CO monitor?

Wondering if you were seeing any elevated CO readings to give a hint of the turbo’s declining health...

PP thoughts only, not a mechanic...

Best regards,

-a-

I have a CO2 monitor, it has never given an elevated reading. 

[thinwing]

During 25 hr oil changes,it is really easy to check turbo condition.It takes maybe 5 additional minutes to inspect with light and mirror ALL exaust joints,turbo vband clamps,compressor wheel free play and runout by loosening out flow clamp and revolving compressor blades by hand.Checking wastegate lever action with an adjustable wrench on out put arm.Than liberal use of mouse milk on every joint and wastegate pivot.Dont forget to wiggle vband clamps...mine were replaced last annual and they took a set..needed to be retorqued...”gently “this is reason I think all turbo owners should be doing there own oil changes.Even my wife ,knows what to look for!

[aviatoreb]

The word mouse milk always makes me laugh.  I imagine a mouse farm with lots and lots of little heifer mice hooked up to tiny milking machines, squeaking and milking their special lubricant.

Edited August 7, 2020 by aviatoreb

[Geoff]

If you think milking a mouse is hard try milking a cat! ala Meet the Fokkers!  or is that Fockers...

Edited August 7, 2020 by Geoff

[aviatoreb]

1 hour ago, Geoff said:

If you think milking a mouse is hard try milking a cat! ala Meet the Fokkers!  or is that Fockers...

The Fokkers made a very nice airplane.

 

[Mooneymuscle56m]

6 hours ago, kortopates said:

Wow - all I can say is how lucky you are before things got much worse. More than likely, the next thing that would have happened in flight, and more likely or sooner at a higher altitude flights where its spinning faster, that the loose bearing housing would have been pumping more and more oil out the exhaust. You might have even noticed that oil consumption had already been higher on some flights as opposed to others, with the higher flights burning more oil and lower flights being normal.  

When things started to fail, would the pilot have noticed the oil pressure declining in flight as the oil pump started cavitating from lack of oil, i.e. dropping out of the green and into yellow? If not the seizing turbo and loss of power would  certainly alert the pilot. Such things were not that far off in the future if this was left unchecked!

So glad it got discovered while you were safely on the ground and this is just a great learning experience rather than unnecessary test of finding an airport to land now! 

Thanks for sharing

BTW, everything your MSC said is spot on, I'd expect mid-time TBO life on the turbo. Some only go 800 hrs some go even longer than your 1300 but that is great. It also sounds like you were running it pretty gentle at a low LOP power mostly. May I ask what your cruising TIT was? This had nothing to do with turbo cool downs. But I assume you weren't operating the turbo as new owner till late in its life, so the question about TIT is really for how it was operated before you bought it and I would suspect it was very near max TIT at high power.

Incidentally, inspecting involves touching and wiggling virtually everything on the aircraft that we want to verify the security and integrity of which includes  every hose and every component that could get loose. Exhaust leaks sure help to draw our attention in.

I am very fortunate to have access to a good shop. My TIT runs in the 1550 ballpark in cruise.  I usually do 4-6 hour legs with stock fuel tanks.  
 

Also never has any abnormal oil consumption.  

Edited August 7, 2020 by Mooneymuscle56m

[Mooneymuscle56m]

2 hours ago, thinwing said:

During 25 hr oil changes,it is really easy to check turbo condition.It takes maybe 5 additional minutes to inspect with light and mirror ALL exaust joints,turbo vband clamps,compressor wheel free play and runout by loosening out flow clamp and revolving compressor blades by hand.Checking wastegate lever action with an adjustable wrench on out put arm.Than liberal use of mouse milk on every joint and wastegate pivot.Dont forget to wiggle vband clamps...mine were replaced last annual and they took a set..needed to be retorqued...”gently “this is reason I think all turbo owners should be doing there own oil changes.Even my wife ,knows what to look for!

You are absolutely correct. I consider myself a fairly handy guy, but have no formal aviation maintenance training, I usually look for obvious things.  I will be adding a turbo wiggle to my checklist when the cowl is removed. 

[N231BN]

We had very poor turbo life while running 15w-50 on a Cessna 414. It may have been poor operating technique by the other owner or just bad luck but there weren't any problems while running 100W.

I know another shop owner that strongly discourages the use of 15w-50 in a turbo as well.