252 Turbo loss - exhaust gasket failure

[Bryan]

Did a short hop over to OK from AR for a buddy that needed to pickup his 172 from the shop. Flight there was normal, we flew over at 12,000 and landed without issue. On the way back, solo, I filed for 17,000. Runup was normal. The runway was rough and I was concentrating on keeping the bouncing airframe in ground effect to build airspeed to notice the Turbo (or not) kicking in.

Fast forward several minutes later, I look down and my MP is near 36” instead of the normal WOT (wide open throttle) 39” (Encore 252). I work the throttle in to make sure I didn’t have a knob back and make sure prop and mixture is full-in, and continue to watch the MP. It slowly drops as I climb. I contacted ATC and asked to level at 15,000. At this point the MP had dropped back to 32” at WOT and CHT #3 (right above the Turbo) is 40* warmer (or more) than normal and higher than normal EGTs. I have the older EDM 700 with no data logging so no data except for pictures of the display.

I pulled back everything and cruised the rest of the flight with more throttle than usual but at 28” at 15k (assumption very little Turbo help) and landed back home no issue.

This is a new to me 252 Encore and been noticing some white exhaust suit coming out or staining the access panel for the fresh air intake, picture attached. Same kind of stuff on my belly from the exhaust. 

I am thinking I had some type of Turbo failure but unsure. I’d almost like to take it out to the runway and run it down the runway with full power to “feel” the turbo kick in (or not) but worried about further damage. Obviously abort the TO without feeling the Turbo kick in and mangaged back down by the automatic wastegate.

Thoughts?    Should I try that or just pull the turbo and send it off?

-bryan

 

 

 

Note: The picture of the EDM 700 was not in-sync with my capture rate with my phone so every other readout is offset. Notice #3 bar graphs compared to the others.

 

 

[L. Trotter]

Don't fly your plane until this is fully assessed by a knowledgeable A&P. To pull 32 in at 15,000 ft would suggest at least partial turbo function. A big concern is exhaust (turbine) leak which (if present) will be come a major hazard to your safety- ie. fire. Additionally the turbine could fall apart internally and deliver far more than compressed air into your engine....ie. metal.

[carusoam]

First things that come to mind....

1) Your MP is still higher than 29.92...  usual for NA at sea level on a standard day...

2) Can’t get that without some level of TCing...

3) Could be the TC is working, but a leak may be occurring...

4) Got Any JPI data to review or share?

5) If it is a hose leak, you might be able to find it by looking. Checking all the hoses and their hose clamps to see if something is amiss...

6) as LT pointed out above, the driver of the turbo is exhaust pressure.  If that pressure is escaping under the cowl it can be a cutting torch... (very serious)

NA Pilot Ideas only, not a mechanic or turbo flyer...

Best regards,

-a-

[CaptRJM]

I would agree that it is probably a leak preventing you from making full boost. It looks like exhaust leaking from around the access door. When is the last time the V Band clamps were looked at?  

You do not want to fly to the plane with a suspect turbocharger!  Have a qualified person look at it!

[Bryan]

I have a sensorcon CO2 sensor in my cockpit and pretty low (normal) readings today. It’s right in my face so I would notice higher CO2 readings. I will de-cowl and take a look. 

Thanks for the input, will get someone to look for leaks around the turbo and V-Band clips; no idea on their last inspection. The plane has a fresh annual.

[carusoam]

@Bryan...

The access panel pic sure is a sign... of something.

If the paint marks weren’t there before the flight, Something is happening on the other side... Is it burnt paint? Something like oil escaping through the gap?

Got a screw driver to remove that panel, if it is a removable panel...? Otherwise decowling is a good idea if able...

Was your annual done by a Mooney familiar shop? They  should be able to tell you if they have removed or loosened the V band clamps.

Then you need to know if these are the do not reuse kind... on the Bravo they are a do not re-use expense...

PP ideas only, not a mechanic...

Best regards,

-a-

 

[neilpilot]

6 minutes ago, Bryan said:

CO2 readings

Drop that 2, and realize that there's a real fire risk if you have a turbo exhaust leak

[Bryan]

 

Just now, neilpilot said:

Drop that 2, and realize that there's a real fire risk if you have a turbo exhaust leak

I am just assessing the data after an uncommon observation in flight. I had the detector and use it as part of my scan. I will not fly until proper assessment can be made.

 

5 minutes ago, carusoam said:

@Bryan...

The access panel pic sure is a sign...

If the paint marks weren’t there before the flight, Something is happening on the other side... Is it burnt paint? Something like oil escaping through the gap?

Got a screw driver to remove that panel, if it is a removable panel...? Otherwise decowling is a good idea if able...

Was your annual done by a Mooney familiar shop? They  should be able to tell you if they have removed or loosened the V band clamps.

The “stain” seems like exhaust suit and wipes off like it does under the belly, not burnt paint. I can easily remove the panel but probably a decowl and inspection is in order. Ron Fisher at All American’s home field did the annual before I acquired the plane in February. He is familiar with Mooney’s but not an MSC.

[MIm20c]

My turbo was not making proper boost and I’m in the process of sending it to main turbo for them to IRAN it. My mechanic is going over everything else (doing my annual a couple months early) while I wait.  I feel your pain but did not want to risk another flight until the problem is found. 

[Bryan]

Ahh, just got the CO “carbon Monoxide” vs. CO2 reference. Yes, serious stuff, thanks

[carusoam]

Exhaust soot would be a real sign...

Got Ron’s number? It may be helpful to send this thread in his direction as well...

If the V band came loose, getting a new one on the way is probably an important part of your next steps.

a quick peek behind the panel might give you the indication of if it was the clamp or the pipe that has failed. A pipe failure can be a hole or broken weld... exhaust leaves a stain at the leak...

Aviation CO monitors are very sensitive,  Sensorcon should be able to see this, If it is exhaust... Other Makes may not be sensitive enough....

Still just a PP, not a mechanic.

Best regards,

-a-

[mike_elliott]

30 minutes ago, Bryan said:

but probably a decowl and inspection is in order

You bet your life it is!

[carusoam]

Bill Gilliland reminder...

MS friends still helping us out years after they moved onto a higher plane...

 

Best regards and respect always,

-a-

[milotron]

BTW it looks like you have a data logging serial port for the JPI up and to the left from the display...or am I mistaken?

 

2 hours ago, Bryan said:

I have the older EDM 700 with no data logging so no data except for pictures of the display.

 

 

[Bryan]

No outputs on this one, just screws, buttons (step/lean find) and a blurry picture.

[Geoff]

Bryan,

Once you get the cowls off look at the intake tubes and rubber connectors as well.

One of the clams holding a rubber connector came loose on my 231 and I had similar symptoms excluding the soot around the turbo.

Geoff.

[kortopates]

The exhaust soot found by the induction panel is really a sign of a significant exhaust leak which of course will rob you of MAP.
As others have said this is very serious since the exhaust leak, once it develops, can be like a torch and grow in size causing more damage and eventually an engine fire and or failure.

Given the location it’s more likely a popped or leaking cyl exh gasket around #3 but could also be an exhaust tube or turbo itself. This engine isn’t very prone to cracking of the turbo case, but it happens.

Likely not the V clamp, since that is lower and further aft. BUT you can and should be gently wiggling the tail pipe with every pre-flight to check the security of the V clamp. It shouldn’t move. You don’t need to decowl the engine to check the V band clamp - just grab the tail pipe to check its secure.
This is an important pre-flight check! (And should be covered in transition training on all turbo’s)

Getting back to the exhaust leak, it should be very obvious with the cowling removed - just look for the source of any grey soot you find. Looking for any evidence of leakage is part of every 25 hr service or oil change. The only normal location is on your belly aft of the exhaust tail pipe.

Unless the turbo is the source of the leak it is likely fine.

Let us know what you find.


Sent from my iPhone using Tapatalk

[carusoam]

Bryan,

What Milo is pointing out to you is the method of downloading data from your JPI...

In your pic, The 1/8” socket at the top/left of your JPI has a matching plug connected to a serial plug, that can be connected to a USB plug that can be used with any computer... check around your plane’s interior pockets for any plugs and wires the PO may have left for you...

Check the JPI website for all the details on the various plugs and cords and programs that you can use...

Since you was.... You might be interested in another service that some MSers use...

for your consideration only...  https://www.savvyaviation.com/savvyaviation-home/savvy-services/savvymx/

This helps you get the most out of your JPI.  It can pinpoint what happened, when it happened, and how long things may have been going on....

If you are not an engineer, mechanic or computer person... Savvy has some help for that too.

Paul can let you in on better details than this if you are interested...

PP pilot working on my own skills, not a mechanic or Savvy sales guy...

Best regards,

-a-

[Bryan]

I see that plug now, above the JPI display and to the left. I will dig thru my box of goodies to see if I have a matching cable. If so, I doubt I have any computers with a serial connection any more but might find a COM adapter for the serial to USB now days. I had thought about upgrading this to the JPI 730 (and still might) but that $1300-$1500 might be better to go toward the 900 with new CiES senders; still undecided. I want/need data logging and download to upload to Savvy. It is literally my next step for this plane. Again, this 252 is new to me but I had a 231 and an Executive before.

I do check the tailpipe for wiggle at preflight but my turn-around in Oklahoma was only 30 minutes and my abbreviated preflight does not normally include that check a second time on the return flight. Might better include that every time now I know the elevated risks.

The plan is to decowl tomorrow and investigate the source of the problem. Next step is to get my local A&P to also look deeper but it’s nice to have MS (you guys) to start with things to narrow the search. Thanks, will report back.

[milotron]

There is a specific USB-serial adaptor that JPI recommends. It can be had through them or from Amazon and others. It is kind of a pain using this and the vintage software that it works with, but it gets the job done.

Sure looks like an exhaust leak at the cylinder junction heating up the CHT so high.

 

iain

[Bryan]

Good to know; I’ll look for that.

My #2 CHT reads higher than normal b/c that is where the factory bayonet prob is located and the JPI is on the bottom spark plug. Piggy-back adapter ordered to replace the spark plug to take its reading from the same location as the factory probe.

[carusoam]

https://www.jpinstruments.com/product-category/adapters-and-cables/

This is what the serial cable looks like...  probably 9 pin?

JPi also has the USB adaptor to connect this cable with a modern PC. I just can’t find on the website where it is hiding.

I bought my USB adaptor throug wallmart.com one day...

Best regards,

-a-

[Cruiser]

You will likely see just the opposite in temp readings although not too much.

Putting the piggy-back thermocouple on will read slightly lower than the other cylinder temps.

[Bryan]

Figured so, that is why I want to go to the EDM900 to be able to remove the factory probe and gauge. My current setup shows #2 with 50* above the others normally, this with brand new baffles. JPI says I can move the spark plug to the top cylinder but figured I would start with a new probe.

[chrisk]

Let us know what you see after decowling.   I would expect an exhaust leak to be reasonably obvious, or at least they have been on the NA engines I have seen.