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MT P860-3 Prop Gov fail.

>>If somehow you didn't overspeed your engine/prop you got very lucky. The other recent (identical?) failure wasn't so fortunate:
http://www.vansairforce.com/communit...ight=overspeed

Might be worth a look at engine monitor data, if you have a record.<<

Thanks for that link. I hadn't seen that and the pix look almost exactly like mine. The only difference is that there must be two pressure chambers in the unit to maintain pitch because my failure caused the RPM to drop rather than overspeed. I was about 18-19 on the RPM at full throttle and 800 on idle descent. Aside from everything else, the landing was much different due to lack of drag. First time I ever slipped the airplane to be honest to get the sucker down as a go-around would have been a nightmare. A short field would have been dicey. Good things to think about and practice on a routine basis.
 
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I'm confused about something, perhaps somebody can clarify.

As I understand it, single engine airplanes with constant speed props are set up to go to fine pitch, not coarse, upon loss or reduction of governor oil pressure - so that you can still make power.

Twin engine airplanes with constant speed props are set up to go to coarse pitch (feather) upon loss of governor oil pressure - so that you minimize drag on the side with the failed engine.

Yet this incident seems to indicate that an RV-10 (single engine) went to coarse pitch, with 500 RPM lower than expected upon governor failure, which seems strange.

This seems to be a different failure mode than the Todd Stovall RV-10 failure from another thread [or at least different symptoms - coarse pitch (lower RPM) instead of fine pitch (potential overspeed)] - that is, unless this is a prop set up for a multi-engine installation, which seems very unlikely.

What am I missing here?
 
Dan,

No,

The temptation is strong, but I don't want to go there until I know what recourse options I can expect. I am getting conflicting advice as to whether to get the FAA involved in this or not. My natural tendency is keep experimental aviation free of Feds, lawyers, etc. However, this is a certified part and three fails in a short period is a GIGANTIC RED FLAG. This is a ticking bomb that when it goes off, you've got about 10 mins to get on the ground or be a glider with a seized engine. I guess I was lucky that the failure caused coarse pitch instead of overspeed, because the latter can trash an engine on top of everything else.
As much as I would like to keep our community "pure", I would feel terrible if a failure of something I could have alerted to caused damage, injury, or death.

Regardless of where this goes, they are going to want to examine the assembly as it is, not after an amateur inspection. It really needs to go to a NTSB level tombstone lab and before the tombstones are required.
 
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I'm confused about something, perhaps somebody can clarify.

As I understand it, single engine airplanes with constant speed props are set up to go to fine pitch, not coarse, upon loss or reduction of governor oil pressure - so that you can still make power.

Twin engine airplanes with constant speed props are set up to go to coarse pitch (feather) upon loss of governor oil pressure - so that you minimize drag on the side with the failed engine.

Yet this incident seems to indicate that an RV-10 (single engine) went to coarse pitch, with 500 RPM lower than expected upon governor failure, which seems strange.

This seems to be a different failure mode than the Todd Stovall RV-10 failure from another thread [or at least different symptoms - coarse pitch (lower RPM) instead of fine pitch (potential overspeed)] - that is, unless this is a prop set up for a multi-engine installation, which seems very unlikely.

What am I missing here?

I don't know myself yet. My semi educated guess at this point is that there are two pressure chambers within the unit to balance and control the prop position. In this type of failure, there is no loss of pressure from the engine to the PG as the pressure loss is by wall breach of the case instead. I imagine that such is something that the engineers think they have eliminated as a possibility. I suspect that my failure was on the side that caused it to go to coarse pitch, which, in a way, I am grateful for as it kept the engine from overspeeding.
 
Somewhere from a dark dusty corner of my memory I seem to recall that aerobatic planes use a different setup so that if the oil pressure is momentary lost, the prob does not go crazy.

Any chance you have a governor from an aerobatic application?
MT is big in the aerobatic world.

Or, maybe the cobwebs need sweeping.......??
 




Here I have tried to depict two different failures with like orientation. Obviously the data sticker is oriented differently.
Mine (bottom) appears closer to the lever side and slightly more to the right at punchout point. Still remarkably similar.
 
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Mike S, I am no expert, but you are on the right track wrt aerobatic CS props- the springs and counterweights that make low total drag, low rpm and high prop pitch with oil pressure loss are in the propellor, not the governor.

Is there a chance this RV-10 has a prop setup like an aerobatic plane?

Is it possible that the same governor failure will overspeed a prop setup to go fine pitch/climb/high rpm and cause an acro/twin setup prop to go low rpm/coarse/high pitch?

Prop should have limit stops with either setup in both directions? (Not an expert).

I have seen nasty overspeeds in acro before accumulators and governors were all shaken down, limit serttings alone didn't stop overspeeds where counterweights were set for climb pitch/fine with oil pressure loss.
 
shox, this is an awful news for MT owners but I am glad your incident had not resulted in any thing worse.

How old/new is your governer and is there a trend in those that are failing?
 
If you have a 'backwards' prop (aerobatic or twin) you need a 'backwards' governor (supply more oil pressure to increase RPM). If you only have one of tbe two it just won't work right. My guess (just a guess) is that this particular failure jamed the oil control valve wide open, resulting in coarse pitch/lower rpm. If he had actually run out of oil rpms would have gone high.
 
Quick update after dozens of phone calls.

This is what I know.

1. Three failures in short succession all in RV-10's with the same model P-860-3 unit and sold by Van's.

2. Two breached the case, one didn't.

3. Two went to overspeed condition, one, (mine) went opposite to coarse pitch. Overspeed means automatic full split case inspection. Jury still out on mine.

4. Mine was manufactured in 2011 and was outside of their SB which were 2012/2013 vintage units. Don't know on the other two.

5. MT in Florida first said that they had never seen a case where the casewall of the unit was breached. They now have pictures of all three and are going to "get with the manufacturer and get back to me". The tech did confirm that the failure could result in fine or coarse pitch depending on how the eggs got scrambled in the failure. I am going to call Germany tomorrow.

6. Two of the engines were built by Barrett. Alan is aware and working the problem. Third engine was not built by him. At this point I think BPE's involvement is purely coincidental.

7. Van's is aware and concerned obviously. I suggested at the very least that they have an alert and/or banner on their website that this has happened. (while thinking emergency AD in the back of my mind) The answer was that more things have to be determined before that level of action but they are actively engaged.

8. The multiplicity of this has only come together, for me at least, through this forum. Who knows how many similar events have happened in other models of aircraft. After 35 years of flying, I've seen a lot of AD's and SB's for stuff way below the level of what these three failures constitute and the potential danger. The insidiousness of this issue is that you don't know you're losing oil until it is gone.

I hate the thought of outsiders invading our world, and I am not a nervous Nelly, but personally, I would not fly an aircraft with this PG until more is known and this is resolved.
 
One thing that I will add is that I get what experimental aviation is all about and that we exist and are successful because we all absorb liability for own misfortunes.

However, this is a now at least a three peat failure of a CERTIFIED part, each one of which sold carried a chunk of liability insurance cost for just these types of failures that we paid for ourselves in the purchase cost.

I'm not looking for anything other than being made whole and for preventing something like this from happening in the future with, God forbid, less fortunate results.
 
This is a good opportunity for a real forensic examination of the root cause of this failure (*assuming* all three are truly related in cause).

Analysis of the failure and determination of the failure mechanism, especially examination of the metallurgy and fracture faces of the internal failed parts, will be important. Additionally, operating data from the engine monitors may help.

If these are "certified" units, it surely seems that in the interest of safety, a formal investigation is warranted. If not, and a responsible agency doesn't initiate one, it will be up to the interested parties to attempt an impartial analysis.

There are labs that specialize in this sort of work. May I suggest that if the units have not been disassembled yet, and if the FAA or NTSB are not interested, that the parties consider preserving the units until an agreed upon lab is chosen for an analysis. Knowing that a particular part failed is less important than knowing why that part failed (metallurgy, fatigue, manufacturing induced stress, poor design, etc.).
 
I am just getting wind of the failures. Wow. I am truly sorry this has happened. It sounds like 2 happened on fairly low time. Weasel's happened after 1000+ hours? None affected by the MT SB?

Thus, basically, given the little we know, all of us flying are potentially at risk, regardless of total hours, it sounds like? Is that correct?

Jae
 
Risk Assessment

I have an IO-360-M1B with 360hrs and trying to assess what action I should take at this time.
1) Do nothing while waiting for more data.
2) Ground the plane.
3) Replace it with another mfg.

if I want to replace it what other options are there?

Any thoughts on this???
 
Quick update from today's adventures.

1. There are now four confirmed failures. Details on the fourth are forthcoming, but apparently happened on first flight. My flight time was 235 hours, I believe one other was 140ish and another over 1000.

2. Of the three previously known and described here, all three units were shipped by Van's in a five month span of late 2011/early 2012.

3. Alan Barrett gave me a list of things to do to check my engine. Unfortunately, we found significant metal in the finger filter and the main oil filter media. There was only about 12 hours on the oil since last check which was clean.

4. Hartzell said that since mine over torqued instead of oversped, the prop wasn't necessarily toast but because of metal in oil, the prop would need to be torn down and serviced. Hartzell was already fully aware of the situation when I called them.

5: Obviously all red arrows point to MT, with Van's, Lycoming, Hartzell, and BPE being coincidences. (So far). The MT-USA office keeps pointing to the German office which I have yet to talk to because they close at 8:00 am Pacific time and are on some kind of holiday as well.

6. My insurance is AIG with Gallagher. They were very up to date on the issue before I called and are trying to be helpful. They are working with at least one of the other parties as well. An AIG adjuster is meeting with me at the hangar tomorrow.
 
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Silly question.

Maybe a silly question, but are all 540 governors located on the front case of the engine?
 
Now I have a silly question. Is the gov. Operating RPM different at the forward location compared to the rear mount? Bob
 
Now I have a silly question. Is the gov. Operating RPM different at the forward location compared to the rear mount? Bob

Yes, while I'm no expert on governors I did have to learn a bit about drive ratios to make sure I ordered the right one for our narrow-deck IO-540.

The 6-cyls are all up front (I'm fairly certain at least, never seen one that isn't) and have either a .895:1 (narrow deck, slower) or .947:1 (wide deck, faster) drive ratio.

The 4-cyls can be either up front or in the back, and depending on location they have a different drive ratio as well. I *think* that if they are in back they are always .867:1 ratio, which is the slowest of all. Unless of course you have a "D" engine with the single-unit dual magneto, in which case it's the *fastest* of all at 1.30:1, or something like that. If the governor is located up front, I believe they follow the 6-cyl convention above.

So yeah, they all run at different speeds. Very confusing for a seemingly simple question! :)
 
Mike is correct wide deck 540 is .947:1, narrow deck is .895:1, Lycoming 360 front mount governor is .947:1, rear mount is .866:1 or in some cases .850:1. Continental engines 1:1. The reason the propeller went to high pitch is when the flyweight came apart it jammed the pilot spool in the feed position. MT governors are made by Avia.

Sean O'Keefe
Project Manager
Aero Technologies, LLC
1-847-541-1133 ext 109
 
Has there been any report of failure of these MT governer that is mounted to a 360 (four cylinder) engine? Looks like they all have been on a 540.
 
Stock Lycoming or modified?

Does anyone know if the 4 engines that failed are Lycoming Clones with higher horsepower output than stock?

Vic
 
Narrow vs wide deck

So will the MT P-860-3 governor work on both wide and narrow deck 540's?
Johan
 
Mine was a BPE rebuilt C4B5 that I was running as a D4A5.

Mine was also a BPE narrow deck that states "built to D4A5 specs".

I chose low compression 8.5 cylinders over future fuel concerns. I wanted a cruise motor, not a race motor. Data plate states 260 hp.

I seem to recall an issue years ago where Van's was shipping "narrow deck" PG's to wide deck owners who were being told to simply change the clocking.
 
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A front governor is driven from a location near the crankshaft's fundamental vibratory node, which means it would see very little vibratory amplitude even if the crank was doing the Chubby Checker ;)

For the youngsters who may be present: https://www.youtube.com/watch?v=pHGXwQeUk7M

Duh.....wrong!

That's what I get for writing without thinking. The governor is driven off the forward end of the camshaft, which, in terms of torsional vibration, is likely to be a very active location.

Dan
 
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Anybody know off hand what the ratio is for the governor this way I could look for it on my spectrum analysis runs.
 
I am currently in the middle of swapping the MT for the Hartzell and this is not proving to be easy. The control arm location is totally different and it looks like I will be talking to Hartzell in the morning.

Rob Hickman
N402RH
 
I am currently in the middle of swapping the MT for the Hartzell and this is not proving to be easy. The control arm location is totally different and it looks like I will be talking to Hartzell in the morning.

Rob Hickman
N402RH

Please post the reply from Hartzell. I'm in the process of doing the same swap.
 
Does anyone have information on the 4th failure that has been mentioned? Was it also a C4B5?
 
I'm about to hang my engine in a few weeks. I got a standard D4A5 through Van's with the standard Hartzel prop. Looks like Van's is shipping Hartzel governors with the FWF kit, which I got about 6 months ago. Did they used to ship FWF kits with MT governors?
 
I am currently in the middle of swapping the MT for the Hartzell and this is not proving to be easy. The control arm location is totally different and it looks like I will be talking to Hartzell in the morning.

Rob Hickman
N402RH

Rob,

Hartzell has a control arm extension that you need for the RV-10. It's about a $30 part. I don't have the part number handy, but Hartzell will know what you need. There are several three or four year old threads here that discuss the need. Van's supplies the Hartzell governor, but not the required arm.

FP08052013A00017.jpg


bob
 
I'm about to hang my engine in a few weeks. I got a standard D4A5 through Van's with the standard Hartzel prop. Looks like Van's is shipping Hartzel governors with the FWF kit, which I got about 6 months ago. Did they used to ship FWF kits with MT governors?

They've been shipping both for awhile. Prior to about 2011 or they shipped only MT. I got one of the first Hartzell's with no prior notice from Van's. A little surprise when you were expecting a MT. I will say that I'm pleased with the Hartzell. I've stopped by their facility several times since it's about a thirty minute flight away from me. They do provide great support.
 
MT governor

I ordered a MT prop and governor about 3 weeks ago and now see this thread. Just curious, is this a problem with all gov's or just units from a couple years ago?
 
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VAF special, is the sales code you need to mention when you order a PCU5000X. The PCU5000X normally sells for $1,600.00 we will be selling to VAF aviators for $1,250.00 plus shipping. Limited time only, deal will expire October 31,2016. Please contact Mac at 1-847-541-1133 ext 108 or [email protected]
Cheers!

Sean O'Keefe
Program Manager
Aero Technologies, LLC
1-847-541-1133 ext 109
 
Can anyone verify whether the extension arm for the Hartzell gov is needed for the vernier (aka blue knob) installs?
 
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