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MT P-860 Prop gov failure

Auburntsts

Well Known Member
So I was out flying a practice approach and as I reached the MAP and poured the coals on I heard a pop and the RPMs redlined. I immediately pulled power and discovered I had zero prop control. As we were on 15 miles from home, and all other engine parameters were green I opted to limp back at 14-15", 2500-2600 rpm which gave about 90 KTS. After getting home safely we pulled the cowl and discovered that piece of the prop gov case, approx 1/16" wide and 1/2 " long had peeled back for some reason (obviously something internal disintegrated) and spewed oil over the bottom cowl.

28754952311_89906fdeee_z.jpg

28547015660_2c3b914a54_z.jpg

28831029925_4b810598b9_z.jpg


Anyone ever seen of a failure like this?

Anyone have a recommendation for a replacement prop gov (IO-540): MT vs Hartzell?
 
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Sadly, I've seen this in the past. MT= Muehlbauer Terminator. Mine had to go back to Gerd in Atting DE for analysis/repair.
 
MT Governor failure

Todd, I had an MT governor fail during the first flight of my RV10. MT has a service bulletin dated Feb 20 2013, #27, that addresses a seized internal bushing. Probably not the same issue you had but I would highly recommend everyone checking out the SB who has an MT (Serial #'s are listed in SB).
I will post more in the future about my experience (had an engine overspeed).
Rick
#40956
Southampton, Ont
 
So I was out flying a practice approach and as I reached the MAP and poured the coals on I heard a pop and the RPMs redlined. I immediately pulled power and discovered I had zero prop control. As we were on 15 miles from home, and all other engine parameters were green I opted to limp back at 14-15", 2500-2600 rpm which gave about 90 KTS.

Good work getting back on the ground.

I'm curious to know whether you had the prop low pitch stop set so the rpm early in the take-off roll was a bit less than 2700, with the rpm increasing as the airspeed increased until it started being controlled by the governor. Or, was the prop being controlled by the governor even at very low speed, which would imply the low pitch stop was set finer than needed.

It is generally recommended to adjust low pitch stops so that the engine cannot quite make rated rpm during the first part of the take-off roll. This sets the low pitch stop a bit coarser than the way many props are delivered, and really helps if there is ever a governor failure.

The opposite is true for aerobatic props, which go to coarse pitch if the governor fails. On aerobatic props, the high pitch stop is the one that can be adjusted by the builder, and it should be set as fine as you can get away with. If it is set too coarse, the rpm will sag to very low values if the prop governor fails, making it impossible to make enough power maintain altitude.
 
Todd, I had an MT governor fail during the first flight of my RV10. MT has a service bulletin dated Feb 20 2013, #27, that addresses a seized internal bushing. Probably not the same issue you had but I would highly recommend everyone checking out the SB who has an MT (Serial #'s are listed in SB).
I will post more in the future about my experience (had an engine overspeed).
Rick
#40956
Southampton, Ont

Rick, I did check SB 27 and my serial number wasn't one of the ones listed in the SB. I am in contact with MT-USA and they are looking into the problem and are shipping me an exchange unit to get me back in the air.
 
Good work getting back on the ground.

I'm curious to know whether you had the prop low pitch stop set so the rpm early in the take-off roll was a bit less than 2700, with the rpm increasing as the airspeed increased until it started being controlled by the governor. Or, was the prop being controlled by the governor even at very low speed, which would imply the low pitch stop was set finer than needed.

It is generally recommended to adjust low pitch stops so that the engine cannot quite make rated rpm during the first part of the take-off roll. This sets the low pitch stop a bit coarser than the way many props are delivered, and really helps if there is ever a governor failure.

The opposite is true for aerobatic props, which go to coarse pitch if the governor fails. On aerobatic props, the high pitch stop is the one that can be adjusted by the builder, and it should be set as fine as you can get away with. If it is set too coarse, the rpm will sag to very low values if the prop governor fails, making it impossible to make enough power maintain altitude.

It's adjusted to make 2650, which is what I think the standard factory setting is--I installed it out of the box without changing anything but the control arm clocking. FWIW, I had the prop set at 2400 when the incident happened, about an hour into the flight and the 3rd approach of the day.
 
Did the screen on the gasket have any metal on it? Kinda vlooks like the flyweight arms carved their way through the body. Might want to pull your oil filter too.
 
Possible overspeed...

I'm going to pull my engine data tonight and see what RPMs I actually hit and for how long -- to be honest I simply don't remember. After reading the posts here and and reviewing some overspeed threads plus the Lycoming Service Bulletin on overspeed, I've potentially got some major inspections on the engine and prop before returning the plane to service, assuming everything checks out. UGH!!!!! :(
 
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Did the screen on the gasket have any metal on it? Kinda vlooks like the flyweight arms carved their way through the body. Might want to pull your oil filter too.

No -- it was clean as were the shaft and splines on the gov itself.
 
MT Governor failure

Todd, you probably already know about the Lycoming SB that deals with over speeds? #SB369M.
This is why I had an engine tear down.
Opps, just saw your 2nd last post.
Rick
 
Recommend looking at the PCU-5000X governor. This is what I have on my RV-10 and recommend it.

Carl

I believe this is the same JIHOSTROJ made for both companies.

Todd - How many hours on the governor? How many years in service?
MT has a 2000 hour TBO or 6 years in service before inspection. For some reason, JIHOSTROJ has a 7 year inspection interval, same TBO.
The shop that just rebuilt mine stated to me that MT no longer supports this governor. However, parts are readily available from JIHOSTROJ. They peeled off the MT sticker affixed over the JIHOSTROJ data plate, so now my governor is officially a JIHOSTROJ, not an MT anymore....
 
I believe this is the same JIHOSTROJ made for both companies.

Todd - How many hours on the governor? How many years in service?
MT has a 2000 hour TBO or 6 years in service before inspection. For some reason, JIHOSTROJ has a 7 year inspection interval, same TBO.
The shop that just rebuilt mine stated to me that MT no longer supports this governor. However, parts are readily available from JIHOSTROJ. They peeled off the MT sticker affixed over the JIHOSTROJ data plate, so now my governor is officially a JIHOSTROJ, not an MT anymore....

1 year and 3 months for 138 hours TT.

MT Germany is shipping me one (I've already received the invoice) although if my log review shows an overspeed, which based upon my luck I feel is likely, then there's no rush as I'm not flying anytime soon as the engine will have to be pulled, torn down, and inspected per Lycoming SB 369L. In any event, parts I think would be a non-issue as this thing is now nothing more than a paperweight -- no one is going to fix it.
 
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Saw photos of a recent catastrophic internal governor failure. The result was a loose chunk. It didn't cut the governor case, but if I understand correctly, it did wreck the governor drive. Think real hard about that.

Perhaps the owner will join in. He elected to buy a new 540.

If this governor is also used in certified applications, it's starting to smell like an AD.
 
It was me.....

Saw photos of a recent catastrophic internal governor failure. The result was a loose chunk. It didn't cut the governor case, but if I understand correctly, it did wreck the governor drive. Think real hard about that.

Perhaps the owner will join in. He elected to buy a new 540.

If this governor is also used in certified applications, it's starting to smell like an AD.

Will take me some time to compile all the information. Basically cruise around 177 knots at 9000ft when it let go. Saw 3700 RPM on the EFIS but datalog only caught it at 3480 rpm. Broke something in the governor drive I can feel a broken tooth when rotating the gov. Drive. MT guy in Florida took the governor apart and said he has never seen this but documented it and sent it back.
 
Saw photos of a recent catastrophic internal governor failure. The result was a loose chunk. It didn't cut the governor case, but if I understand correctly, it did wreck the governor drive. Think real hard about that.

Well that pretty much seals the deal on a tear down I think. The governor's drive shaft will no longer rotate by hand which I believe it's suppose to so I'm guessing that means something inside the engine's gov drive assembly probably sheared.

For those who have faced this kind of thing before, should I give my insurance company a call to start a claim process at this point? Is this even claimable (man I'm so ignorant on this kind of thing)?
 
Teardown it is

Well I had an overspeed - from the moment on the missed approach when I advanced power to until I figured out something was seriously wrong and transitioned to VFR whikle reducing power. That delay is going to prove very costly.

I've read through SB 369L and the teardown and inspection is extensive. Is this something I trust to my local guy or bite the bullet and ship it back to BPE from whence it came?
 
Overspeed

Following a normal take off and climb proceedures I arrived at 9000ft and leveled off. Was talking with Gulfport approach at the time. Set up for cruise LOP and autopilot for a nice smooth cool ride. Something like 3 minuets latter instantly the engine overreved much like the sound of a 16 year old trying to speed shift his newly acquired 69' Camaro with a Big Block and a 4 speed from 2nd to 3rd and hits 1st with foot on the floor and drops the clutch.

I glance at the EFIS at the same instant I pull the throttle back and remember north of 3700 RPM. (Latter pulling the EFIS file shows a lower number but I think the recorder was set on 2hz updated so it may have missed the highest excitement). It seemed like forever till it slowed enough to drop below 3000 RPM. First thing I remembered Picayune was directly below. Called ATC and told them I had a loss of power and needed lower. He immediately cleared me to 4000ft and said Picayune at your 5 oclock and 2 miles cleared to deviate left or right direct picayune when able.

So we circled down. Engine was still running good but prop control did nothing when changed settings. I tried slowly speeding the motor back up but it would go past red line at low MAP so I was certain the prop was on the low pitch stop and not moving. I didn't want to try anything more for fear loosing oil but nothing was on the windscreen which is good.

ATC asked if we had a complete power loss or only partial? I told them partial and the engine was still running.

Canceled IFR somewhere around 2500ft when I was sure we had the field made. Landing and taxi was a non event and just left the throttle at idle all the way in.

Soon as I landed the maint. guy comes out and said hey Gulfport approach wants to know if you made it.......yeh we made it thanks for checking on us!!! They were great.

Removed the Governor and immediately noticed when the engine is at a specific position that the female spline gear in the engine could rotate aprox. the distance of several gear teeth so I assume when the governor locked up that it stripped some teeth off the governor drive gear, the governor idler gear or the front cam gear.

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I sent the Governor to MT in Florida. There response was "Governor is scrap due to overspeed" which we all know is incorrect. The overspeed was a result from the Governor failure not the other way around...

I paid them to take it apart and send it back to me.

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I just discovered I have one of the governors that is covered by SB 27. My -10 is now grounded until I hear back from MT on the replacement procedure.

I am so glad, this thread popped up and prompted me to look. :eek:

Shannon
 
MT governor failure

Guys, the other fact I wondering about. is, since the MT SB came out in 2013, was Vans ever told about it and/or did they keep sending MT governors with the kits?
I combed their web site and correct me if I'm wrong, but I see no mention of any MT service bulletin. This doesn't help,the situation either.
Rick
 
Guys, the other fact I wondering about. is, since the MT SB came out in 2013, was Vans ever told about it and/or did they keep sending MT governors with the kits?
I combed their web site and correct me if I'm wrong, but I see no mention of any MT service bulletin. This doesn't help,the situation either.
Rick
You titled your post " MT Governor failure "? Then go on to question the SB issued by MT. Neither mine nor the original poster have governors that are affected by the SB. They are 2 separate issues.
 
Question

I had my MT Governor overhauled in June 12, 2102. Serial # 09G054G

Can someone see if my governor is on the list. My computer will not allow me to access the SB from MT.

Tiffin Aire did the work.

Thanks,
Darren Kerns
RV7 N599DT
 
MT governor (failure)

So Weasel, at this point, do you know for sure that your issue was NOT caused by an internal issue with the bushing being involved? The same could be asked about Todd's? While you are correct that the 2 afore mentioned governors may not be part of the SB, my point is that all 3 appear to have caused an engine over speed which may have caused significant engine damage, and, I'm wondering if Vans was ever told of the SB by MT? Seems like a reasonable question to me.
Rick
 
Guys
I got in to see the SB. It looks as if my governor does not apply.

I hope I am reading it correctly.
Thanks,
Darren
RV7 N599DT
 
Seems like a reasonable question to me.
Rick

Sure, it's a reasonable question but you can see in the picture that a portion of the fly weight pin bracket broke off letting the weight depart off the pin. I don't think a bushing had anything to do with it. Also MT-USA disassembled it for inspection and said they have never seen this before.
 
Harmonics?

Both of the failures discussed in this thread were on -540's. Is anyone aware of similar MT governor failures on four cylinder Lyc's? I'm wondering if this could be a harmonics issue on the -540...


Skylor
 
Well I had an overspeed - from the moment on the missed approach when I advanced power to until I figured out something was seriously wrong and transitioned to VFR whikle reducing power. That delay is going to prove very costly.

I've read through SB 369L and the teardown and inspection is extensive. Is this something I trust to my local guy or bite the bullet and ship it back to BPE from whence it came?
Also consider the prop. Hartzell and MT both publish inspection requirements as a function of the max rpm. They also publish rpm values at which the prop should be scrapped, and that rpm could have easily been exceeded in this event.
 
Both of the failures discussed in this thread were on -540's. Is anyone aware of similar MT governor failures on four cylinder Lyc's? I'm wondering if this could be a harmonics issue on the -540...Skylor

Mine was installed on an AEIO 360 in a Pitts
 
So I was out flying a practice approach and as I reached the MAP and poured the coals on I heard a pop and the RPMs redlined. I immediately pulled power and discovered I had zero prop control. As we were on 15 miles from home, and all other engine parameters were green I opted to limp back at 14-15", 2500-2600 rpm which gave about 90 KTS. After getting home safely we pulled the cowl and discovered that piece of the prop gov case, approx 1/16" wide and 1/2 " long had peeled back for some reason (obviously something internal disintegrated) and spewed oil over the bottom cowl.

28754952311_89906fdeee_z.jpg

28547015660_2c3b914a54_z.jpg

28831029925_4b810598b9_z.jpg


Anyone ever seen of a failure like this?

Anyone have a recommendation for a replacement prop gov (IO-540): MT vs Hartzell?

...I have seen this before and never got the opportunity to speak with the unfortunate sole behind the stick! I am interested in two things, first, was this so violent that it took out the governor drive? Second question is, how much oil loss was involved in what amount of time? Thanks, Allan...:confused:
 
...I have seen this before and never got the opportunity to speak with the unfortunate sole behind the stick! I am interested in two things, first, was this so violent that it took out the governor drive? Second question is, how much oil loss was involved in what amount of time? Thanks, Allan...:confused:

I'm not sure about the status of the engine's gov drive assembly, but since the gov's drive shaft is now "frozen" and won't turn at all, it's logical to assume that the drive assembly has been damaged although there isn't anything visible from outside of the case. We'll know for sure in few weeks once BPE tears the engine down.

As for the oil, I lost at least 1/2 quart, probably a little more. I started the flight at 8qts and have a bit more than 7 now.
 
I'm not sure about the status of the engine's gov drive assembly, but since the gov's drive shaft is now "frozen" and won't turn at all, it's logical to assume that the drive assembly has been damaged although there isn't anything visible from outside of the case. We'll know for sure in few weeks once BPE tears the engine down.

As for the oil, I lost at least 1/2 quart, probably a little more. I started the flight at 8qts and have a bit more than 7 now.

...Thank you for the instant reply! Allan
 
Might not be worth the effort considering what you are facing but since the governor is off already, your only one hose and four nuts away to remove the governor adaptor. I don't know if there is a shear pin in the adaptor or not.
Might be a waste of time considering you may be faced with a tear down anyway.
So sorry to have this happen.
 
Might not be worth the effort considering what you are facing but since the governor is off already, your only one hose and four nuts away to remove the governor adaptor. I don't know if there is a shear pin in the adaptor or not.
Might be a waste of time considering you may be faced with a tear down anyway.
So sorry to have this happen.

Yeah, unfortunately I had a large overspeed so I have to have it torn down. I'm working through those machinations right now with the Insurance adjuster and the engine shop (BPE). Still waiting to hear back from Hartzell on what I need to do for the prop as my search did not turn up and equivalent SI/SB/SL to Lycoming's SB on overspeeds.
 
Since the OP asked about alternatives, I'll just state that I chose the Hartzell governor. No issues for me, nor have I heard of any from anyone else.
 
Since the OP asked about alternatives, I'll just state that I chose the Hartzell governor. No issues for me, nor have I heard of any from anyone else.

You sure it's a Hartzell? Certified ?
I was sure my MT was an MT. It isn't. MT relabeled the JIHOSTROJ unit. Stuck their labor right over the top of the data plate. They quit doing that some time ago and started doing there own thing or using a different OEM. The JIHOSTROJ isn't what failed on this OP's airplane. It is a newer MT or ?
JIHOSTROJ Shows Hartzell as one of their distributors, just like PCU5000, which is a JIHOSTROJ according to the shop I used.
A certified governor should set you back several thousands of $$. If it is experimental, chances are it is a relabeled JIHOSTROJ.
 
I too opted for the Hartzell certified gov. Vans sent me the MT and I sent it back for exchange. I don't remember if more dollars were involved, it was to long ago.
I would certainly approach MT for reimbursement of the 10K it may cost for the tear down and possible replacement of the crankshaft as Rick has had to do as a result of the overspeed. It's starting to sound like a recurring issue to me.....
 
I too opted for the Hartzell certified gov. Vans sent me the MT and I sent it back for exchange. I don't remember if more dollars were involved, it was to long ago.
I would certainly approach MT for reimbursement of the 10K it may cost for the tear down and possible replacement of the crankshaft as Rick has had to do as a result of the overspeed. It's starting to sound like a recurring issue to me.....

Are you sure? The Hartzell Vans currently carries appears to be the experimental one, which I believe is the JIHOSTROJ.
Thus far, I haven't heard of failures like this from them.
The price is around $1300, which is about the same cost on exchange or rebuild of a certified unit.
So, if it is certified, nobody would ever have one rebuilt as it would cost the same as new. Something does t make sense.
 
Are you sure? The Hartzell Vans currently carries appears to be the experimental one, which I believe is the JIHOSTROJ.
Thus far, I haven't heard of failures like this from them.
The price is around $1300, which is about the same cost on exchange or rebuild of a certified unit.
So, if it is certified, nobody would ever have one rebuilt as it would cost the same as new. Something does t make sense.

Quick call to Vans, they think they are all certified, at least the tech I talked too.
 
And the hits keep a comin'....

The bad news -- I heard back from Hartzell and I'm now the proud owner of a pristine 80", 2-bladed, scimitar shaped wall decoration. :eek:

The good news is it's look my insurance will cover it. Sigh....:rolleyes:
 
Did Hartzell refer to a specific over-speed duration or max exceeded RPM?

Both -- they have a chart with percentage over max RPM on the Y-axis and Duration in seconds on the X-axis (MT-prop uses a similar chart BTW). Depending where you fall on the chart determines whether no action is required, inspection, overhaul, or scrap. In my case it was percentage over max RPM and not duration that killed my prop.
 
You have a great attitude about all of this Todd.

Well **** happens, and so far my insurance underwriter hasn't given me a reason to panic--yet. Right now the estimate is north of $21K and that's before they find anything that needs to be replaced outside of the prop.

The worst part for me at the moment is:
A: I now have a 12-hr drive one-way ahead of me to Florida (and then back) next week instead of a 4 hr flight.

B: Yesterday my painter e-mailed me that my slot on the wait list had finally arrived for 19 Sep. Luckily he found someone further down the list to swap with me so now it's Mar 2017.
 
Todd,
Great news about the insurance, I thought for certain they would tell you to pound sand. I wonder if they will subjucate the claim to MT.
 
Todd,
Sorry to hear about your troubles and great job handling it.

Whenever and if you feel comfortable sharing which insurance company you are insured with, I would appreciate it as it is good to know those insurance companies who are there for you when you need them.
 
Gosh Todd. Congrats on keeping your head and making it back. Same for keeping your head and working through all of this. Hopefully the insurance company will take care of it---or most of it.
Keep us informed!
Tom
 
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