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MT P-860 Prop gov failure

Housing interference

Joel,

Sorry to hear of your issues and damage. Hope you get it resolved and back in air soon as I know your RV10 is utilized frequently.
Question, Do you think it is possible the weights interfered with the housing prior to catastrophic failure? Do you think it is the reason for the weight snapping the ear of the retaining pin because the weights interfered with the housing?
 
Joel,

Sorry to hear of your issues and damage. Hope you get it resolved and back in air soon as I know your RV10 is utilized frequently.
Question, Do you think it is possible the weights interfered with the housing prior to catastrophic failure? Do you think it is the reason for the weight snapping the ear of the retaining pin because the weights interfered with the housing?

I dont know for sure but there is very little scoring of the case internally so I think it happened when the ear broke. Also every thing abnormal looks "fresh".

Nothing looks like it had been wearing over time.
 
My governor is the 860-4 mated to an IO 320 with a Hartzel prop. Since I'm at 5 years and the recommended overhaul is 6 years according to the folks at MT I spoke with, I decided to send it for overhaul. At $550, is seems prudent, given recent experiences. It will be interesting if they find anything. I'm sorry you all have gone through the malfunction and resulting troubles but am grateful for you sharing your experiences.
 
My governor is the 860-4 mated to an IO 320 with a Hartzel prop. Since I'm at 5 years and the recommended overhaul is 6 years according to the folks at MT I spoke with, I decided to send it for overhaul. At $550, is seems prudent, given recent experiences. It will be interesting if they find anything. I'm sorry you all have gone through the malfunction and resulting troubles but am grateful for you sharing your experiences.

That is considerably less than what I just paid. Who are you using?
In another thread, it was questioned why a perfectly working governor would have a calendar year limit. Many folks are not aware of this,
Or don't care, and run them to TBO, and probably beyond. I chose the rebuild path as you are. Considering the circumstances, Inwould say you are wise to do this.

Outside of this circumstance, there is another option, if your governor is working and you don't have concerns like is being brought up in this thread. You can have an "inspection and re-seal". They replace all of the seals, visually inspect and check for limits. They don't magniflux all of the parts. So, it is a short cut that is about half the cost, but would be better than just letting it go to TBO.

Again, considering these problems, I wouldn't be taking any short cuts.
 
That is considerably less than what I just paid. Who are you using?
I called MT directly in Deland. They gave me a quote of $550 for overhaul. I also called American Propeller in Redding, Ca and they were $900+ for the same service..
 
My governor is the 860-4 mated to an IO 320 with a Hartzel prop. Since I'm at 5 years and the recommended overhaul is 6 years according to the folks at MT I spoke with, I decided to send it for overhaul.

The manual that Dan provided a link for seems to indicate there is no TBO

erich
 
PCU5000 Governor

The Jihostroj governor is marketed here in the USA by
Aero Technologies, LLC. Aero Technologies, LLC is the FAA/PMA holder of all
certified units. The PCU5000X is the same as a certified unit, except it is set to the owners specifications. Jihostroj made MT governors prior to 2004. Part number start P-920 or P-940 are an older design, they physically look different from the current models. Hartzell Propeller, Inc. manufacturers
their own S-1 design governor for the homebuilt market. The PCU5000 has a large service center network with Propeller and Accessory shops that can sell new or overhaul these governors. New units can be ordered direct, email to: [email protected], Maciej "Mac" Paszkowski-Sikorski is our sales representative. PCU5000 has been an advertiser on this website for years and continues to support the GA/Homebuilder aircraft community.

Sean O'Keefe
Project Manager
Aero Technologies, LLC
1-847-541-1133 ext 109
 
As a result of the reported failures of MT P-860-3 prop governors posted here in the forums, Van's has contacted MT-Propeller USA (the supplier of the gov. that have been sold by Van's). Van?s has supplied to MT any available information on those failed governors that were sold through Van?s. ie: Date of delivery, Time in service etc.

MT USA has indicated to Van?s that they are currently acting on those reports. Rather than having information flow from multiple sources (with the confusion that can often cause), Van's is referring customers directly to MT-Propeller USA to obtain assistance in determining if their governor is at risk of failure. MT indicated to Van?s that they are happy to work directly with our customers regarding this issue.
 
The manual that Dan provided a link for seems to indicate there is no TBO

erich


Yes there is a TBO. Its 2000 hours and/or 72 months.

MT Propellers
ATA 61-20-48 Operation and Installation Manual
Hydraulically Constant Speed Governor
P-8( )( )-( )
Link: http://www.mt-propeller.com/pdf/manuals/e-1048.pdf

Specifically, page 4, states in part:

1.1.1 Overhaul
Overhaul is a periodic process and contains the following items:
- disassembly
- inspection of parts
- reconditioning of parts
- reassembly
The overhaul interval is based on hours of service (operating time) or on calendar time.
At such specified periods, the governors should be completely disassembled and inspected
for cracks, wear, corrosion and other unusual or abnormal conditions. As specified, certain
parts should be refinished, and certain other parts should be replaced.
For overhaul interval for the governors please refer to Service Bulletin 1



MT Propellers
Service Bulletin No. 1 R1
Subject: Time Between Overhaul of Propellers, Governors and Oil-Accumulators (TBO)
Aircraft affected: All with these Propellers, Governors and Accumulators


Link: http://www.mt-propeller.com/pdf/sbs/sb1r1.pdf

Specifically, Page 10 states in part:

5.2 Time Between Overhaul (TBO) Governor:


Governor: P-8( )( ) - ( ) Piston and Turbine engines 2000 hours 72 months
 
Last edited:
Follow-up

As a result of the reported failures of MT P-860-3 prop governors posted here in the forums, Van's has contacted MT-Propeller USA (the supplier of the gov. that have been sold by Van's). Van?s has supplied to MT any available information on those failed governors that were sold through Van?s. ie: Date of delivery, Time in service etc.

MT USA has indicated to Van?s that they are currently acting on those reports. Rather than having information flow from multiple sources (with the confusion that can often cause), Van's is referring customers directly to MT-Propeller USA to obtain assistance in determining if their governor is at risk of failure. MT indicated to Van?s that they are happy to work directly with our customers regarding this issue.


E-mail address for contacting MT tech support in EU.

[email protected]
 
Yes there is a TBO. Its 2000 hours and/or 72 months.

MT Propellers
ATA 61-20-48 Operation and Installation Manual
Hydraulically Constant Speed Governor
P-8( )( )-( )
Link: http://www.mt-propeller.com/pdf/manuals/e-1048.pdf

Specifically, page 4, states in part:

1.1.1 Overhaul
Overhaul is a periodic process and contains the following items:
- disassembly
- inspection of parts
- reconditioning of parts
- reassembly
The overhaul interval is based on hours of service (operating time) or on calendar time.
At such specified periods, the governors should be completely disassembled and inspected
for cracks, wear, corrosion and other unusual or abnormal conditions. As specified, certain
parts should be refinished, and certain other parts should be replaced.
For overhaul interval for the governors please refer to Service Bulletin 1



MT Propellers
Service Bulletin No. 1 R1
Subject: Time Between Overhaul of Propellers, Governors and Oil-Accumulators (TBO)
Aircraft affected: All with these Propellers, Governors and Accumulators


Link: http://www.mt-propeller.com/pdf/sbs/sb1r1.pdf

Specifically, Page 10 states in part:

5.2 Time Between Overhaul (TBO) Governor:


Governor: P-8( )( ) - ( ) Piston and Turbine engines 2000 hours 72 months

I called Harzell to inquire about their governor which seem to be the exact replacement with no modification needed. They indicated that theirs has a 2400 hour TBO with no calendar time limitation. If the cost of an overhaul is around $800 which some have been quoted for, it seems to make sense to switch to a new Harzell, at lease this is what I would do.
 
I called Harzell to inquire about their governor which seem to be the exact replacement with no modification needed. They indicated that theirs has a 2400 hour TBO with no calendar time limitation. If the cost of an overhaul is around $800 which some have been quoted for, it seems to make sense to switch to a new Harzell, at lease this is what I would do.

Bavafa,

Yes. It does make sense. Thanks for the info. I looked it up. You are correct "(there is no calendar limit applicable to governors)". Hartzell Governors that is. Thanks for posting. I see you are in SAC?

HARTZELL PROPELLER INC.
SERVICE LETTER
HC-SL-61-61Y

Propeller - Overhaul Periods and Service Life Limits for Hartzell
Propeller Inc. Aviation Components -
Propellers, Governors, and Propeller Damper Assemblies
April 01/04
Revision 4, Nov 06/13
HC-SL-61-61Y
Page 20 of 28
D. Governors
(1) Hartzell Propeller Inc. propeller governors are to be overhauled at the same
time as engine or propeller overhaul, but not to exceed 2400 hours of operation
(there is no calendar limit applicable to governors).
 
Update....

So the engine teardown has begun. As expected, the prop gov drive assembly is toast. What wasn't expected was apparently one of the exhaust valve tappets broke and ping-ponged around. The good news is it doesn't appear that the case has been cracked, but they are going to dye it to be sure -- hopefully I will dodge that bullet. So far we know all of the the valve springs will be replaced and all the other components will be pulled and measured for service limits. I would expect that additional valve train components will need to be replaced. More to follow....
 
So the engine teardown has begun. As expected, the prop gov drive assembly is toast. What wasn't expected was apparently one of the exhaust valve tappets broke and ping-ponged around. The good news is it doesn't appear that the case has been cracked, but they are going to dye it to be sure -- hopefully I will dodge that bullet. So far we know all of the the valve springs will be replaced and all the other components will be pulled and measured for service limits. I would expect that additional valve train components will need to be replaced. More to follow....

Ouch. What rpm did it hit during the overspeed, and how long was it up there?
 
3250 for 10 sec. I was flying a missed approach at the time and actually did not know the magnitude of the overspeed until I pulled the engine data log the next day.

Wow - I wouldn't have predicted that 3250 rpm would lead to a failure in the valve train.
 
3250 for 10 sec. I was flying a missed approach at the time and actually did not know the magnitude of the overspeed until I pulled the engine data log the next day.

Wow. I wonder what will be found in my engine. It will likely be late this winter or early spring till I have time to tear into it. It went to 3496 RPM and was over 2700 for a while but would have to look up the duration. Pretty sure it was less than 10 sec. going from memory.
 
Wow - I wouldn't have predicted that 3250 rpm would lead to a failure in the valve train.

Well I'm not going to jump to any conclusions one way or the other. The tappet failure could be purely coincidental, or perhaps it was on it was already well on its way to failure and the overspeed just accelerated the process--who knows?

My only advice is if you have an overspeed, read Lycoming SB 369L very carefully, and contact your prop and rotating accessory manufacturers for potential impacts. In my case my prop, and 1 of 2 of alternators exceeded specs and had to be replaced. I also went ahead and replaced the 2nd alternator as it was real close to the manufacturer's max limit and as I have an all electric airplane and fly IFR a lot, I deemed it prudent to replace.
 
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.

Update for all those that have been inquiring how this worked out.

I opted to buy a new engine so the Insurance paid the estimated over speed inspection cost along with engine removal and reinstallation. They also paid for the new prop. Sure it didn't pay for every thing I am out of pocket such as hangar rent at the remote airport and travel back and forth but I am pleased with the service provided by Hallmark.

The new engine now has ~5hrs total time on it. Time will tell how it works out.
 
Well I'm not going to jump to any conclusions one way or the other. The tappet failure could be purely coincidental, or perhaps it was on it was already well on its way to failure and the overspeed just accelerated the process--who knows?

My only advice is if you have an overspeed, read Lycoming SB 369L very carefully, and contact your prop and rotating accessory manufacturers for potential impacts. In my case my prop, and 1 of 2 of alternators exceeded specs and had to be replaced. I also went ahead and replaced the 2nd alternator as it was real close to the manufacturer's max limit and as I have an all electric airplane and fly IFR a lot, I deemed it prudent to replace.

Likely, not just due to overspeed but if the exhaust stem was tight then overspeed just triggered a stuck valve then the gap to the tappet did the rest. Either way, an overspeed creates a real mess.
 
Hey Todd, Get your engine back yet? Let us know if you found anything else broke. I have been running the new engine a while now and if I can find time later in the winter I may tear into the broken one.

BTW sure has been quite from MT.
 
Hey Todd, Get your engine back yet? Let us know if you found anything else broke. I have been running the new engine a while now and if I can find time later in the winter I may tear into the broken one.

BTW sure has been quite from MT.

Not yet. Next week I plan to give either Rhonda or Allan a shout to see where they're at with it.
 
Epilogue....

So it's been almost 5 months since my prop gov self destructed and shelled the engine on my RV-10, Finally got it back from BPE this past Wed and got it mounted today:

31792156316_c092da5b59_z.jpg

31829655305_669ac5f8de_z.jpg


Now just a few things to tidy up (fuel and oil lines, throttle body, air box, exhaust, primary alternator, starter, sensors, p-leads, electrical wiring, control cables, ring gear, prop, prop governor, and baffles) and we're back in business.

It was supposed to be on the in the paint shop right now getting finishing touches on it's paint job, but I had to give up my slot. Luckily I was able to swap with the guy behind me so I'll get it painted in March.
 
Nice. Don't be a moron like I was and try and crank it with the fuel still shut off. The first flight will almost be as memorable as the original. It feels great to get back "normal", but I must confess that I listen more to the engine now than i did before ... perhaps I always will.

Perhaps we can meet up at OSH and take a group photo. :)

Good luck and Merry Christmas.
 
rev limiter

One feature of EFII and SDSEFI... a rev limit fuel shut-off function in case of governor failure or blade loss.
 
MT Service Bulletin - misleading conditions

As some have noted, MT's service bulletin 31 (http://www.mt-propeller.com/pdf/sbs/sb31.pdf) says the MT governor flyweight failure problem applies to engines "modified with electronic ignitions or higher compression pistons." At least one of the RVs that had an MT governor fail had dual magnetos and stock pistons. It's been reported on VAF that this has been brought to MT's attention. MT has not changed the service bulletin in the intervening months.

Based on MT's unwillingness to honestly describe the failure condition in their service bulletin, I lost confidence in MT and pulled the MT governor from my plane in January. I replaced it with a PCU 5000, which has noticeably better performance than the MT governor (the PCU doesn't have the rpm hunting that the MT had).

At OSH this year, I spoke with MT about the fact that their SB is misleading, in that there have been failures in engines without either electronic ignition or high compression pistons. It was amazing to hear the blamestorming from the German-accented MT rep at OSH. "What about McCauley governor failures" "What about Whirlwind propeller failures." I pointed out that the issue at hand was MT's failure to publish an honest, complete service bulletin. The MT rep continued to attack other products, rather than address MT's Service Bulletin shortcomings.

I'm glad I got rid of the MT governor on my plane several months ago. Based on the behavior of MT on this issue, I'll advise all prospective builders I meet not to use MT products.
 
I had one of the failures. As best as I have been able to determine, the very first failure of the batch that had the design change that caused the failures happened in Europe with a high performance aerobatic aircraft that had high compression pistons and EI. IMO, that laid the foundation to their thinking. However, all of the remaining failures (4 known 2 more rumored) in the US and Canada were stock stock.
 
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