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-   -   MT P860-3 Prop Gov fail. (https://vansairforce.net/community/showthread.php?t=140879)

vic syracuse 08-23-2016 10:48 AM

Unfortunately, I have to agree, Weasel. It's not making any sense to me right now, and hasn't for the last week. First, I think the data field for the failures is kind of low---yes, they might be from a close-timeframe batch, but there sure is a large time-in-operation spread between them. For piece of mind for me in the meantime I am changing the governor to a PCU5000X (I was going to use a Hartzell, but got the wrong one shipped from Van's last week). I currently have about 1100 hours on my P-860-3, and had it overhauled at 950 hours.
Something must have changed in the manufacturing process for the MT governors, and I hope we can find out soon.

BTW, the The P-880 governor someone mentioned in an earlier thread is for a counterweighted prop. The P-860-3 is the correct model for the RV-10.

Vic

Auburntsts 08-23-2016 10:58 AM

Quote:

Originally Posted by Weasel (Post 1105778)
Anyone care to venture why they mention electronic ignition and high compression. The failures here do not support the remark.

It's a head scratcher. Besides having only mags (as already noted), I have stock 8.5 low compression pistons.

I'm still curious as to how they are able to come out with an SB and a fix so fast being that outside of external pics they have not examined either Myron's nor my PG.

Weasel 08-23-2016 12:02 PM

Quote:

Originally Posted by Auburntsts (Post 1105810)
It's a head scratcher. Besides having only mags (as already noted), I have stock 8.5 low compression pistons.

I'm still curious as to how they are able to come out with an SB and a fix so fast being that outside of external pics they have not examined either Myron's nor my PG.

Well, hopefully this information will get back to them before they actually publish the SB.

DanH 08-23-2016 12:06 PM

Quote:

Originally Posted by Auburntsts (Post 1105810)
It's a head scratcher. Besides having only mags (as already noted), I have stock 8.5 low compression pistons.

I'm still curious as to how they are able to come out with an SB and a fix so fast being that outside of external pics they have not examined either Myron's nor my PG.

Perhaps you three are not the only failures.

GaryK 08-23-2016 12:15 PM

Vic,
Is the PCU5000 the same form factor as the MT. I have the Sam James cowl and plenum so the PG cylindrical shape is important unless I modify the plenum.

Thanks
Gary

Auburntsts 08-23-2016 12:19 PM

Quote:

Originally Posted by DanH (Post 1105832)
Perhaps you three are not the only failures.

My thoughts as well, although you would think that multiple failures would be relatively common knowledge--perhaps not. However, methinks that something was already in the works based upon some kind prior knowledge, especially since the SB is apparently going to target only a specific manufacturing date range of the model and not all of them.

vic syracuse 08-23-2016 01:31 PM

I have scoured the Internet and can't find any other failures, which I find hard to believe.

I will le tyou know on the form factor.

Vic

rvbuilder2002 08-23-2016 01:47 PM

Quote:

Originally Posted by Weasel (Post 1105830)
Well, hopefully this information will get back to them before they actually publish the SB.

I have fwd'ed the details about the 3 RV-10's that have been provided here, to Martin at MT.

woxofswa 08-23-2016 05:09 PM

This gets more confusinger by the day. I dug deep into my documents and there is a card (mostly in German), that says that the 860-3 is specified for 360
Series engines and 2500 RPM.

I've had supposed experts say that the ratio difference of WD and ND is a big huge ticking bomb deal and others say that it is very minor that all it does is slightly vary the speed of the pump and slightly change the distance throw of the arm to make a given change. I've heard of a well known pilot who purposely runs a ND ratio pump on his WD because he likes the feel better and had never had a
problem. The external gear on my failed unit is in pristine condition.

I emailed MT, sent my pictures, and offered any help I could and they never answered me back.

Chkaharyer99 08-23-2016 05:11 PM

Quote:

Originally Posted by vic syracuse (Post 1105807)
Unfortunately, I have to agree, Weasel. It's not making any sense to me right now, and hasn't for the last week. First, I think the data field for the failures is kind of low---yes, they might be from a close-timeframe batch, but there sure is a large time-in-operation spread between them. For piece of mind for me in the meantime I am changing the governor to a PCU5000X (I was going to use a Hartzell, but got the wrong one shipped from Van's last week). I currently have about 1100 hours on my P-860-3, and had it overhauled at 950 hours.
Something must have changed in the manufacturing process for the MT governors, and I hope we can find out soon.

BTW, the The P-880 governor someone mentioned in an earlier thread is for a counterweighted prop. The P-860-3 is the correct model for the RV-10.

Vic

Vic,

Thank you for the post. It helps validate the decision I made.

The MT P860-4 on my RV-8 was due to be sent back for the six year inspection/rebuild... MT quoted me $800.00 for the service and indicated a two week turn around.

After reading about the MT prop governor issues you all were having on the RV-10's (MT P860-3) I decided to ground my plane, remove the MT PG and apply the $800 dollars I would have spent on the MT PG rebuild towards a brand new PCU-5000X from Aero.

Aero sold me a new PCU5000X for $1,200, comes with a warranty and isn't due for a rebuild for 72 months. Should have a new one in five days. It seemed the prudent way to go.

To those of you who have had PG failures. Good job getting your planes safely on the ground. Best wishes in your resolving your problem at the lowest possible expense. Most of all, thank you very much for sharing your experiences with us.

GaryK 08-23-2016 06:26 PM

Vic,
Here are a few pics of the "form factor" I was asking about. For some reason the second pic is upside down (looking in the cowl inlet)

Thanks
Gary

[IMG][/IMG]


Kellym 08-24-2016 08:30 AM

Quote:

Originally Posted by woxofswa (Post 1105924)
This gets more confusinger by the day. I dug deep into my documents and there is a card (mostly in German), that says that the 860-3 is specified for 360
Series engines and 2500 RPM.

I've had supposed experts say that the ratio difference of WD and ND is a big huge ticking bomb deal and others say that it is very minor that all it does is slightly vary the speed of the pump and slightly change the distance throw of the arm to make a given change. .

It is clear that the P-860-3 will work on both the wide and narrow deck engines. It is also clear that it has the gear ratio specified for the narrow deck. The rpm specified is for the governor, not engine rpm, so 2700 times the gear ratio give. s you the governor rpm.
What is not clear is why Vans chose this version, when they have always sold wide deck engines, and the P-860-5 has the correct gear ratio for that engine. Also, MT's application document recommends a P-860-19 for the RV-10 with an MT 12B prop. Don't know anything about that version of the governor.
My P-860-5 is going back to MT today to have the SB31 done on it.

vic syracuse 08-24-2016 08:49 AM

I confirmed this week that the P-860-3 is the correct governor.

Vic

Weasel 08-24-2016 09:12 AM

Quote:

Originally Posted by Kellym (Post 1106092)
My P-860-5 is going back to MT today to have the SB31 done on it.

Without the SB31 being published how do you know it needs to be done? Are you aware that maintenance induced failures are a reality?

Bavafa 08-24-2016 09:41 AM

Does any one know the difference between a P860-4 and P860-3. I just looked up my paperwork and it indicates I have a P860-4

civengpe 08-24-2016 10:30 AM

Juergen from MT USA told me today that all P-860 are the exact same except for the clocking. He said he doesn't understand why MT does it that way, because it is very confusing.

This came up, because I asked him why the MT applicability chart shows the P-860-19 as the appropriate PG for the IO-540-D4A5, but MT sold me the -3.

Also, the SB has now been pushed back to Monday next week.

Please don't shoot the messenger here. I am only parroting what I was told an hour ago by MT. I am not a PG expert and barely have an idea of how the dang things work.

woxofswa 08-24-2016 10:47 AM

Quote:

Originally Posted by vic syracuse (Post 1106104)
I confirmed this week that the P-860-3 is the correct governor.

Vic

Can I ask who confirmed that and for what application? I'm at the point where three experts have four opinions on the matter. Not literally, but I'm definitely stuck right on top of the VOR if you catch my azimuth.

scsmith 08-24-2016 03:44 PM

Service interval?
 
I'm just discovering this thread, kinda late, but I think I read through all the details.

I checked my paperwork, and my MT P-860-4 governor was manufactured in 2008 (thankfully outside the affected time period), and has been in service since September 2009 -- so, 7 years. It has 400 hrs on it.

From this thread, I just learned that there is a 72-month service interval in addition to the 2000 hr service interval. That surprised me. Can someone speculate or explain why there would be a 6-year service limit on a prop governor? I would think that calendar age would have no bearing at all on the service life, except perhaps for age-hardening of elastomeric seals.

If this service interval should be respected, I am a year overdue, and from what I have learned in this thread, it costs $800. It would seem a sensible choice to consider just buying a PCU-5000X instead.
Another alternative would be to ignore the calendar-based service interval and just operating the MT P-860-4.

I would love to hear supporting arguments for why a 6-yr service interval should be respected on a prop governor.

Thanks

Bavafa 08-24-2016 04:00 PM

Quote:

Originally Posted by scsmith (Post 1106228)
I'm just discovering this thread, kinda late, but I think I read through all the details.

I checked my paperwork, and my MT P-860-4 governor was manufactured in 2008 (thankfully outside the affected time period), and has been in service since September 2009 -- so, 7 years. It has 400 hrs on it.

From this thread, I just learned that there is a 72-month service interval in addition to the 2000 hr service interval. That surprised me. Can someone speculate or explain why there would be a 6-year service limit on a prop governor? I would think that calendar age would have no bearing at all on the service life, except perhaps for age-hardening of elastomeric seals.

If this service interval should be respected, I am a year overdue, and from what I have learned in this thread, it costs $800. It would seem a sensible choice to consider just buying a PCU-5000X instead.
Another alternative would be to ignore the calendar-based service interval and just operating the MT P-860-4.

I would love to hear supporting arguments for why a 6-yr service interval should be respected on a prop governor.

Thanks

Steve,
I am in exact same boat as you are with the age/model of the governor and only slightly more hours, at 560 now. I have asked MT via e-mail this question and for a quote but if there is convincing evidence for this overhaul at 6 year interval, I will certainly go with Harzel governor which does not have this calendar base overhaul requirement. With only $400 or so more, I will put a brand new instead of an overhauled one.

GaryK 08-24-2016 04:26 PM

Based on some of the information posted by those who have spoken to MT directly there is a specific date range. Can we assume the new units being shipped by Vans today are OK.

vic syracuse 08-24-2016 04:59 PM

I confirmed the governor model as being correct with the chief inspector for MT-USA. Yes, I know there seems to be lots of conflicting data. But there sure are a lot of them flying for it to be the wrong one.
My guess on this, and it is ONLY my guess, is that they made a change in the manufacturing/assy process during a specified timeframe and have probably seen enough data from the overhauls to affect a SB once these flight failures occured. That might explain why they can act on an SB so fast without having seen the actual failures.

Vic

Kellym 08-24-2016 10:52 PM

Quote:

Originally Posted by Weasel (Post 1106116)
Without the SB31 being published how do you know it needs to be done? Are you aware that maintenance induced failures are a reality?

I emailed Peter Marshall, manager of MT-USA, and he replied that my governor was on the internal tentative service bulletin and advised that I send it in.

Kellym 08-24-2016 11:01 PM

Quote:

Originally Posted by vic syracuse (Post 1106245)
I confirmed the governor model as being correct with the chief inspector for MT-USA. Yes, I know there seems to be lots of conflicting data. But there sure are a lot of them flying for it to be the wrong one.
My guess on this, and it is ONLY my guess, is that they made a change in the manufacturing/assy process during a specified timeframe and have probably seen enough data from the overhauls to affect a SB once these flight failures occured. That might explain why they can act on an SB so fast without having seen the actual failures.

Vic

My question is why Lycoming and MT literature show different gear ratios for wide and narrow deck engines IF all P-860 governors are the same except for clocking? Clearly the gear ratio does differ between dash numbers, with the gear shown on the dash 3 model matching the gear ratio for narrow deck engines. Clearly the gear ratio on the -5 and -19 match that called for on wide deck engines.

vic syracuse 08-25-2016 05:35 PM

I can only take their word for it. My guess is that the P-860-3 can be adjusted for a wider RPM range.

Vic

Bavafa 08-25-2016 05:45 PM

I received a response from MT and in addition to what they have previously said and posted here, they added this :
The different between -3 and -4 is the gear ratio .
-3 has an gear ratio of 0,895:1 and -4 has an gear ration of 0,866:1

bcondrey 08-25-2016 05:47 PM

Seems like the subject of compatibility of the MT governors comes up every year or two. Several years ago I researched this same subject because of the single model being sold by Van's. I don't have the references now but the explanation was that the difference in the models was clocking of the arm AND how the max RPM adjustment (stop screw) were set from the factory.

FWIW, you see the same thing on Lycoming engines... An IO-540-D4A5 is identical to an IO-540-C4B5 in the parts book. Only difference is the RPM and HP rating. The C4B5 is rated at 250 HP @ 2575 RPM and the D4A5 is rated at 260 RPM @ 2700 RPM.

Kellym 08-25-2016 09:11 PM

Quote:

Originally Posted by bcondrey (Post 1106579)
Seems like the subject of compatibility of the MT governors comes up every year or two. but the explanation was that the difference in the models was clocking of the arm AND how the max RPM adjustment (stop screw) were set from the factory.

FWIW, you see the same thing on Lycoming engines... An IO-540-D4A5 is identical to an IO-540-C4B5 in the parts book. Only difference is the RPM and HP rating. The C4B5 is rated at 250 HP @ 2575 RPM and the D4A5 is rated at 260 RPM @ 2700 RPM.

Correct Bob.
I went back to my Matronics archives for explanation by the late Jim Ayers, an MT distributor, dba Less Drag Products:
"The -3 and -5 governors are identical, except for the final adjustments.

For the -3 governor on the wide deck IO-540 engine, the high RPM stop screw has to be turned out quite a bit to get to 2700 RPM from the factory setting of about 2550 RPM. (For the narrow deck IO-540 engine, the initial stop setting on the -3 governor would be at about 2700 RPM.)

The -3 governor on a wide deck IO-540 now has a longer travel to get to the low RPM stop. The governor arm should have full travel from the high RPM stop to the low RPM stop.

Perhaps someone already flying can say if they have full travel (stop to stop) available with Van's governor cable.

Full governor arm travel is helpful to have for the mag check so it is possible to get the expected 450 RPM drop when the governor/propeller is cycled.

Jim Ayers"

With the -5 on my wide deck I only had to move the arm to match the cable approach angle.

GaryK 08-26-2016 04:00 PM

Myron
 
Sent you a PM

Thanks
Gary

rv4bill 08-26-2016 07:07 PM

Got the rocket apart for annual and looked at PG serial number.
MT Govenor
Hartzell CS

P-860-3 11g424-g09/11
I'm only a few numbers away from one that failed.

Narrow deck IO 540 C4b5
9.0 to 1 Pistons.
Bendix mags

Guess I'm grounded or at least soon to be when the SB comes out next week🙁

woxofswa 08-26-2016 07:35 PM

Yeah my sticker says 10/11 but my engraved data plate says 9/11 so I would concur that you are at ground zero. Probably same production run. Probably same shipment. Which ultimately may or may not mean anything. This huevada is taking more twists and turns than a Clancy novel.

GaryK 08-27-2016 04:48 AM

I think Vic's guess of what happened is pretty close. In my conversation with MT he mentioned sometime in 2014 they made a change in manufacturing. The flyweights were welded on prior to 2014. They increased the material thickness and pinned one side and welded the other on the models sometime during 2014. He said the actual fix shouldn't take more than 1.5 hours. They only have 3 sets of the new parts and are waiting on more from Germany.

Gary

jtrollin 08-27-2016 12:03 PM

SB Cost?
 
Anyone know if there is a cost for the SB?

Larkrv10 08-27-2016 01:43 PM

Dan, you are correct, although my prop over speed and P-860-3 governor failure was the result of the bushing seizure and SB 27.
Rick
Southampton, Ont





Quote:

Originally Posted by DanH (Post 1105832)
Perhaps you three are not the only failures.


Larkrv10 08-27-2016 01:56 PM

MT governor failure
 
Quote:

Originally Posted by rvbuilder2002 (Post 1105861)
I have fwd'ed the details about the 3 RV-10's that have been provided here, to Martin at MT.

Scott, not sure if you're aware of my failure wrt SB 27. I do think MT is aware of me though.

FWIW, my P-860-3 governor was installed on a narrow deck IO-540 with 9.0 compression.

Rick
#40956
Southampton, Ont

Larkrv10 08-27-2016 02:14 PM

MT governor failure
 
Guys, after realizing my governor self destructed which was found by placing it on a test stand at Tiffin Aire (Tiffin, 0H), MT did send me a new
p-860-3 with a manufactured date in 2016.
I have since completed my 25 hour Transport Canada test period.

When I recover from shoulder surgery and the shock of an almost $11k repair bill to my IO-540, I will be pulling that MT governor off and replacing it with a Hartzell governor.
If anyone wants a cheap slightly used governor let me know.

Rick
#40956
Southampton, Ont

woxofswa 08-27-2016 06:12 PM

Rick,

What the rest of us are waiting to know with baited breath was if our internal failures were triggered as a result of the same bushing failure that you had. My unit hasn't been torn down and inspected and I don't think Todd's has either. The FAA forbade me from sending the unit to MT, but they haven't requested it either. (Those questioning Fed involvement please understand that a report of a component failure in flight is both an FAR requirement and in my case, an insurance requirement.)

Once the laws of physics get angry, anything can happen.


drill_and_buck 08-28-2016 04:42 AM

Quote:

Originally Posted by woxofswa (Post 1107092)
Rick,
.......(Those questioning Fed involvement please understand that a report of a component failure in flight is both an FAR requirement and in my case, an insurance requirement.)

I was not aware of this. Is this true for aircraft registered in the experimental category? Does this mean that if my alternator or my electronic ignition equipment fails in flight I am obligated to report it?

Anyone have a link to the FAR?

Auburntsts 08-28-2016 05:15 AM

Quote:

Originally Posted by woxofswa (Post 1107092)
Rick,

What the rest of us are waiting to know with baited breath was if our internal failures were triggered as a result of the same bushing failure that you had. My unit hasn't been torn down and inspected and I don't think Todd's has either. The FAA forbade me from sending the unit to MT, but they haven't requested it either. (Those questioning Fed involvement please understand that a report of a component failure in flight is both an FAR requirement and in my case, an insurance requirement.)

Once the laws of physics get angry, anything can happen.


Can you provide the FAR ref for the reporting requirement? Ive read through part 21 and I'm aware that there is a requirement for such a report for 121/135 ops, but can't find any such requirement for part 91.

BillL 08-28-2016 05:50 AM

Quote:

Originally Posted by Kellym (Post 1106640)
Correct Bob.
I went back to my Matronics archives for explanation by the late Jim Ayers, an MT distributor, dba Less Drag Products:
"The -3 and -5 governors are identical, except for the final adjustments.

For the -3 governor on the wide deck IO-540 engine, the high RPM stop screw has to be turned out quite a bit to get to 2700 RPM from the factory setting of about 2550 RPM. (For the narrow deck IO-540 engine, the initial stop setting on the -3 governor would be at about 2700 RPM.)

The -3 governor on a wide deck IO-540 now has a longer travel to get to the low RPM stop. The governor arm should have full travel from the high RPM stop to the low RPM stop.

Perhaps someone already flying can say if they have full travel (stop to stop) available with Van's governor cable.

Full governor arm travel is helpful to have for the mag check so it is possible to get the expected 450 RPM drop when the governor/propeller is cycled.

Jim Ayers"

With the -5 on my wide deck I only had to move the arm to match the cable approach angle.

The bold portion was correct for a recent 10 friend first flight. Stock Vans IO540. The adjustment screw did not have enough range, so rearming and reclocking was required. Not a difficult thing, just to get it adjusted properly took several flights. OK in Phase I, but not if you need to spend a few $hundred on fuel just to do this. The MT manuals' adjustment recommendation of rpm per screw flat is correct.

Jackm 08-29-2016 10:49 AM

Ratio
 
Just another curve ball in this governor issue. Our io540 is a wide deck with narrow deck drive gear ratio so 860-3 is correct one for our engine. We were told that the ratio difference is related to Io540 260 HP/vrs 300hp wide deck version but waiting for Aerosport to confirm. Just Fyi.


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