Acclaim--Broken exhaust to turbo transition

[Daniel]

I thought I would post a recent experience here as it may help someone.

I am flying a 515 hour TT Mooney Acclaim.  It is very well cared for and came out of annual 20 hours ago from a service center.

While flying at 19,000 (2400 RPM and 27") I began to notice a slight reduction in manifold pressure.  I adjusted, but it was soon declining again.  I switched from LOP to ROP, but that did not help for long.  Only when I tried to run a higher power setting did I realize that I could not hold even 29" MP at 2500 RPM.  Soon it was back down to 27" at full throttle.  This was not good.

I requested a descent to 11,000 ft. where I was able to hold 28".  I continued my flight, which the AFM says you may do.  It does have some other advice, and I'll come back to it.

I continued onto my destination another hour's flight away, and as I began to descend I was getting cold.  Heater could not keep up.

Long and short of it:  There are two turbochargers, one under each bank of cylinders.  They tie together on the upper and lower decks (with a single waste gate on the lower deck).  On the right side, the two forward cylinder exhausts tie together and come into the forward part of the transition.  The rear most cylinder ties into the top.  The cross over line to the left side  joins the back.  At the bottom of the transition piece there is a flange that connects to the turbocharger.

My transistion piece had broken off completely just above the flange and onto the part that leads to the forward cylinders.  I'd say it cracked in flight and the crack continued until it was a complete disconnect.

Continuing the flight was a large mistake, and I was very foolish.  That was 1600 degree exhaust gas leaking out of the break, and the fire risk was real.  The AFM warns of this, but I guess I did not want to take it seriously on Sunday morning.  As the mechanic said, I was lucky to be in the maintenance hangar the next morning talking about it.

This is apparently a known issue on the right hand side for Acclaims, and there is a service bulletin.  Be careful.

[jlunseth]

At the GAMI seminar I attended last fall, George Braley related a similar story concerning a Bonanza I believe it was, piloted by his brother.  The pilot detected a momentary anomaly in the engine monitor, descended, and when engine power began to fail, was able to make a rough landing in a cornfield.  The NTSB investigator complimented the pilot on the safe landing.  The pilot said that he didn't feel it was a very good landing, the plane being in a cornfield and bunged up.  The NTSB inspector said, "You don't understand.  This is the fourth of these I have investigated, and you are the first pilot I have been able to talk to."

My A&P, which is Willmar, is sort of manic about inspecting the exhaust tubing, and I have had most of it replaced.  I am grateful they don't let any thing short of 100% get by.

[FlyFstr]

Daniel, thanks for sharing that story. 

[KSMooniac]

The GAMI story involved a 310, I believe, which are notorious for exhaust troubles.  IMO, any signs of trouble on a turbo involving loss of MP should lead to a precautionary landing ASAP.

Thanks for sharing the story!  I and am sure everyone else are glad to hear you're around to tell it!

[Piloto]

That's why I love my 201, simple and reliable.

Jose

 

[blacknchrome]

Quote: Piloto

That's why I love my 201, simple and reliable.

Jose

 

[Daniel]

I did not want to mention the service center and give an implied black eye. Let's just say it was a shop with that kind of dedication to detailed exhaust examination.  Assuming that they did that careful of an exam 20 hours before failure, what are we to learn?  Perhaps only that this is a significant issue which even careful maintenance will not prevent. 

We Acclaim pilots had better be ready for this and also hope that there is a good fix coming.

[aschardt]

Valueable lesson learned.  I had a similar expirence in my turbo normalized F model.  I had the plane inspected by an A&P just prior (1 flight hour) to a 1200 mile trip to KDVT.  I had another maintainance issue on the way and had to have the generator replaced while there.  During that maintainance, the A&P at KDVT noticed that the v-band clamp attaching the turbo to the exhaust had failed and the the bracket holding the turbo on had cracked leaking hot exhaust into the engine compartment.  Not sure which failed first, but my guess is the clamp and the subsequent vibration cracked the backet.  I didn't notice a reduction in power and would not have found it if that generator had not failed.  Not a great feeling

[Piloto]

Quote: blacknchrome

The 201 is a great airplane.  But, you can't go the places he can with the Acclaim's capabilities.  Somewhat apples to oranges....

 

I'm glad things turned out alright with the Acclaim in this situation.  Thanks for the description of how things went during that flight.

[vasco]

Jose, i drive an 2007 O3.  It is an outstanding airplane.  Having said that, at least a half dozens times in the last 5 months i could have used the Acclaim to go higher; to avoid enroute weather and take advantage of tail winds.  Having talked to several Acclaim and Columbia 400 owners the problem described in this thread are rare.  The reliability of the Acclaim and other current turbo systems are very high.  Take a look at the Cirrus sales the past two years.

[jlunseth]

Oooooh, Jose I love all your posts, you serve up great, practical advice and it would be a privilege to fly with you some day, but that one needs a response.  

I love my turbo 231 and would not go back to normally aspirated.  The safety it adds, such as flying above most weather, and being high enough to glide to an airport 35 miles away, more than make up for issues with the turbo.  And just for the record, after buying the plane and making some needed repairs, I have not had issues with the turbo.  I am relentless about having it checked periodically and well, and I don't spare cost hoping that a nicked pipe will last a few hundred more hours, it is just not worth it.

The 201 has this little deal with the siamese twin magnetos and that does not go away unless you replace the whole engine.  Very good friends of mine, both flight instructors, were forced to make an off field in a 201, not the twin magnetoes but a stuck throttle cable - stuck closed during a simulated engine out. 

They all have issues.  You pick your poison. The moral of this story is that an accomplished pilot needs to become intimately familiar with the aircraft he or she flies, needs to know its strong points as well as its weak ones, because they all have weak ones.  The pilot needs to know what they are, and how to deal with them if they come up.

Lots of people seem to view pilots as risk takers, but that does not describe any pilot I know.  There is risk in anything we do. We could take a shower, slip, and die.  Pilots are incessant, relentless learners, determined to know what the risks are and how to manage them. 

[rbharvey]

This is SB M20-309 issued in August 2009. I inspect this every 25 hrs during oil change, SB says every 100. first actual I have heard on an Acclaim although others could of been silenced.....Scary not sure how to prevent if this can happen that quickly

[blacknchrome]

Quote: rbharvey

Scary not sure how to prevent if this can happen that quickly

[rbharvey]

Acclaim is for sale, ...actually everything I own is always for sale for the right price :-) Acclaim offers accepted for sure !

[blacknchrome]

Quote: rbharvey

 ...actually everything I own is always for sale for the right price :-)

[Piloto]

Quote: jlunseth

Oooooh, Jose I love all your posts, you serve up great, practical advice and it would be a privilege to fly with you some day, but that one needs a response.  

I love my turbo 231 and would not go back to normally aspirated.  The safety it adds, such as flying above most weather, and being high enough to glide to an airport 35 miles away, more than make up for issues with the turbo.  And just for the record, after buying the plane and making some needed repairs, I have not had issues with the turbo.  I am relentless about having it checked periodically and well, and I don't spare cost hoping that a nicked pipe will last a few hundred more hours, it is just not worth it.

The 201 has this little deal with the siamese twin magnetos and that does not go away unless you replace the whole engine.  Very good friends of mine, both flight instructors, were forced to make an off field in a 201, not the twin magnetoes but a stuck throttle cable - stuck closed during a simulated engine out. 

They all have issues.  You pick your poison. The moral of this story is that an accomplished pilot needs to become intimately familiar with the aircraft he or she flies, needs to know its strong points as well as its weak ones, because they all have weak ones.  The pilot needs to know what they are, and how to deal with them if they come up.

Lots of people seem to view pilots as risk takers, but that does not describe any pilot I know.  There is risk in anything we do. We could take a shower, slip, and die.  Pilots are incessant, relentless learners, determined to know what the risks are and how to manage them. 

[rorythedog]

Quote: Piloto

That's why I love my 201, simple and reliable.

Jose

 

[fantom]

Quote: rorythedog

 my 201 has been as reliable as a car. i've owned this plane 16 years. 

[vasco]

3rd quarter (2010) GAMA results: Cirrus sold 61 new planes bringing them to 188 for the year.  80% of those airplanes are/were the GAMI/Turbo normalized model.  I believe that the data will support that current generation turbo airplanes are very reliable.  I am not going to report how many Mooneys were sold during that same period..........

[maxmax]

I had a Mooney Rocket for 5 years before selling due to rising costs operating back in 2007, namely 21.5 gph !!  I loved the smooth performance of that big turbo Cont. TSIO-520, but it came with added diligence in regards to the power plant.  Granted that the Acclaim is a completely different system with 2 turbos, rather than one big Garrett on the Rocket.  Anyway, I had the oil changed every 25 hours and went over the exhaust system very carefully every time I had the cowl off.  I have never heard of an in flight fire in a Rocket due to an exhaust leak, but I had in other turbos like the Bonanza.  I spoke to one Rocket owner that saw his oil pressure gauge wiggle in flight.  Fortunately, he took it seriously and made an emergency decent in IMC from 15k to a C class airport below him.  He landed ok, but had to shut down the engine on final due to complete oil pressure loss.  Made the airport, and saved the engine.  Turned out to be an oil seal at the base of the turbo.  He never short cut that 5 minutes of cool down again.  I guess the moral of his story that stuck with me was, if something doesn't seem right, don't chance it.  Get on the ground and figure it out.

[Piloto]

Quote: maxmax

I had a Mooney Rocket for 5 years before selling due to rising costs operating back in 2007, namely 21.5 gph !!  I loved the smooth performance of that big turbo Cont. TSIO-520, but it came with added diligence in regards to the power plant.  Granted that the Acclaim is a completely different system with 2 turbos, rather than one big Garrett on the Rocket.  Anyway, I had the oil changed every 25 hours and went over the exhaust system very carefully every time I had the cowl off.  I have never heard of an in flight fire in a Rocket due to an exhaust leak, but I had in other turbos like the Bonanza.  I spoke to one Rocket owner that saw his oil pressure gauge wiggle in flight.  Fortunately, he took it seriously and made an emergency decent in IMC from 15k to a C class airport below him.  He landed ok, but had to shut down the engine on final due to complete oil pressure loss.  Made the airport, and saved the engine.  Turned out to be an oil seal at the base of the turbo.  He never short cut that 5 minutes of cool down again.  I guess the moral of his story that stuck with me was, if something doesn't seem right, don't chance it.  Get on the ground and figure it out.

[M016576]

Quote: Piloto

Jose 

[roundout]

Quote: Piloto

That's why I love my 201, simple and reliable.

Jose