What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

MT P860-3 Prop Gov fail.

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
 
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.
 
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.
 
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
 
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
 
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.
 
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.
 
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🙁
 
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.
 
Last edited:
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
 
MT governor failure

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
 
Last edited:
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
 
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.

 
Last edited:
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?
 
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.
 
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.
 
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.
 
The reference for the Fed report lies within the maintenance side. I believe it is the obligation of the person holding the repairman certificate that will be signing the logbook to report a component that fails in flight.
I'll see if I can get more specific details and references.

My insurance adjuster requested a report to the FSDO. When I called them, they hadn't heard of it and said it would be a regional issue. Next day I got a call from the regional office. He said he was aware of the issue and of multiple failures. He requested pix that I sent. He was the one who told me not to send it to MT. He said that they would have preferred that it had never been removed from the aircraft in the first place. He mentioned the report that would be required and I told him that I didn't have complete information yet. He was fine with that.
He said he or someone else would get right back to me and I haven't haven't heard a another word in over a week.
 
Last edited:
The reference for the Fed report lies within the maintenance side. I believe it is the obligation of the person holding the repairman certificate that will be signing the logbook to report a component that fails in flight.
I'll see if I can get more specific details and references.

My insurance adjuster requested a report to the FSDO. When I called them, they hadn't heard of it and said it would be a regional issue. Next day I got a call from the regional office. He said he was aware of the issue and of multiple failures. He requested pix that I sent. He was the one who told me not to send it to MT. He said that they would have preferred that it had never been removed from the aircraft in the first place. He mentioned the report that would be required and I told him that I didn't have complete information yet. He was fine with that.
He said he or someone else would get right back to me and I haven't haven't heard a another word in over a week.

Please do if you can. I can find no reference that would mandate a pilot or A&P/repairman to provide such a report where there is no accident or damage outside of the aircraft associated with an incident such as ours which occurred operating under part 91. Shoot, I didn't even declare an emergency or request priority handling.

FWIW, I have had no request by my insurance adjuster, the FAA, MT or anyone else for any kind of report. That doesn't mean that someone won't ask for one in the future, just no one has asked for one to this point. Now it could be that the claim paperwork I completed filled that purpose and whatever was germane to the FAA was extracted and forwarded on by the adjuster thereby negating any further action by me-- I dunno.

All this tells me that once again that in our community, the rules it would seem to vary from office to office. In this case we have the same insurance underwriter but different adjusters and of course the same FAA but different FSDOs and yet you had to submit a report and I didn't. :rolleyes:
 
Last edited:
I think what you guys are looking for is not the FARs, but the CFRs dealing with the NTSB (section 830 or something??). But I don't see prop governors on the list. Of course you may always make a voluntary report.
 
I think what you guys are looking for is not the FARs, but the CFRs dealing with the NTSB (section 830 or something??). But I don't see prop governors on the list. Of course you may always make a voluntary report.

I just read through CFR part 830 Subparts A thru D and my conclusion is no NTSB report is required IAW with Subpart D, para 830.15 because the damage is not considered "substantial" by the definition in Subpart A, para 830.2 nor does the incident, as handled in the air and once on the ground, fall under one of the immediate notification criteria as listed in Subpart B, para 830.5.
 
Last edited:
OK, I've done more research. I hope to make the mud a little clearer. Here is the report in question:

http://av-info.faa.gov/sdrx/SubmissionsGeneralAviation.aspx

The first mention of this to me was an A&P IA who was one of the guardian angels who came up to rescue me when I was AOG on the rez. He said that it was a report that we needed to make when we got back home.

The second mention was the insurance adjuster. She asked if I had already done it and when I said I hadn't, she "strongly suggested" that I do it right away. Since she had yet to tell me if my claim would be accepted I was "strongly motivated" to keep her happy so I told her I would contact the FSDO that afternoon. (I can see how getting FAA involved helps AIG subrogate against MT).

The third reference was when the regional Fed called me. He also asked if I had done it and I told him I was still collecting information.

Now where the gray seeps in. This report mirrors a similar report that licensed repair stations are required to submit on failed components. There is debatable school of thought that as the repairman certificate holder of this aircraft, we become the station required to report. Some say yes, some say no. As merely owners/pilots we are allowed and encouraged to report, but perhaps not required.

When I spoke to the shop that has my propeller (Hartzell authorized repair and distribution center) they told me that they had already made their report on the issue and that a report by me would just go in the same file as their report.

Sorry if I confused anyone with previous posts. I'm not sure if the mud is clearer or not.

My primary concern is just making sure that this thing is resolved before anyone gets hurt or worse.
 
Another data point in all this...

So, I've been curious to see if the MT governor in my RV-7 would be affected by all of this and when the SB didn't hit the wire today (again), I took matters into my own hands and called MT-USA and was connected to Peter.

Up to this point, my governor has operated with no issues. (Fingers crossed that continues.)

I gave him my model and serial number (P-860-4 and 11G146-G) and I was relieved to find I will be unaffected by the bulletin, even with a production date in 2011-around when some of the bad ones came off the line.

I did ask him (had I been affected) would sending the unit in for the SB service have also satisfied the 72 month overhaul requirement and was told it would not have...that's a separate service not included in the fix.

Next question was..(for those that are close to the O/H time limit and DO need the SB performed)...what is the "upcharge" to do the O/H if done while it's already apart and getting fixed for the SB and the response was "we haven't decided on pricing yet, but since it's already apart it wouldn't be much...a couple of hundred bucks maybe?"

Like I said above...a data point for others with these things installed.

Thanks to the folks posting on this thread who have had governor failures for all the info shared-it is very much appreciated!

Rob
 
Not on the naughty list!

Just got off the phone with Peter at MT after giving him my serial number. There were a few earlier than my serial number and a bunch after. He looked up my individual number and said mine was OK!

He is forwarding to me an email document this am with the SB 31 as it is not showing on MT's German site yet.

If someone gives me their email, and is proficient at posting a doc, I will forward the email so it can be posted here on the site for all interested to see.
 
Marvelous. They changed the design of the flyweight assembly in July of 2013. Somebody had concerns, theoretical or actual, and there were only 175 serial numbers with the problematical design. How hard would it have been to declare a fix three years ago?
 
I see the SB applies only to engines modified with electronic ignition or high(er) compression pistons.
Have there been any failures on stock engines?
 
I see the SB applies only to engines modified with electronic ignition or high(er) compression pistons.
Have there been any failures on stock engines?

Yes--mine for one (2 mags, 8.5 pistons), Myron's for 2, a third did have lightspeed and one mag. MT was made aware of this from multiple sources to include both Vans and BPE -- disappointing that they chose to publish that misconception in the SB even after they were told it was false.
 
Last edited:
Bob

I asked Peter about the compression/EI part of the SB.

He stated that if your serial number is on the list AND you have either electronic ignition OR higher compression Pistons then you should not fly until repaired. If you have standard / stock engine ( no EI and no higher compression) then follow SB as shown.

Didn't make sense to me either as some of the failures seemed to be "stock".
I asked Peter to join the discussion to put rumors to rest and tell us straight up, "what's up". He said his company policy doesn't allow anyone to participate in forum discussions as they tend to turn ugly.

He seemed very willing to take any calls about the SB or prop governor question anyone may have.
 
It was amusing to me to see my serial number on the SB list.

I find the whole EI/High comp thing to be curious as none of the recent failurees apply. Something smells to me that there was a previous failure(s) that was quietly investigated. They sure seem confident about the weights assembly fix and yet they have not even inspected the two specimens that breached the case wall. I've sent them two emails that they've never answered.

I would be very curious to know what PG Van has on his personal 10
 
Last edited:
SB Cost

I called them on the SB cost.
No charge other than shipping.

Since mine would be due for an overhaul in 18 months or so, I asked what that cost would be if they did it at the same time as the SB. Since they have it apart the OH cost is $250.

Gary
 
I just got off the phone 1 minute ago with Peter. I told him that not a SINGLE one of the recent failures would apply to the SB as written.

His answer was "we are just a service center, all inquiries of that nature must be directed back to the factory."

Now we know that they've known about the problem since 2013.

Excuse the melodrama, but my wife and I had 2-3 minutes of sustainable oil left when I landed. If I had been just a few miles further south I would have been off airport and choosing between sheep trails, lava rock, or forest. Having not known that I was going to be dead stick until it seized. (Not that an abandoned airport on the Rez is far from off airport).

Rant off. Thank God nobody has gotten hurt (that we know of).
 
Yes--mine for one (2 mags, 8.5 pistons), Myron's for 2, a third did have lightspeed and one mag. MT was made aware of this from multiple sources to include both Vans and BPE -- disappointing that they chose to publish that misconception in the SB even after they were told it was false.

The copy that has been produced as we have it, was not "published" on the MT website. Maybe there are still changes being made?
 
FAA Report Not Mandatory

The Service Difficulty Report form in Post #127 cites a FAR 121.703 requirement. Part 121 applies to Air Carriers (scheduled airlines), not to experimental aircraft operating under Part 91. That said, informing the aviation community of a product defect is a good thing even if not mandatory.
 
That's true, but the link was sent to me from the Feds, and the title on the link said "general aviation". Typical Fed way of paper tracking.
 
MT Governor failure

Yes--mine for one (2 mags, 8.5 pistons), Myron's for 2, a third did have lightspeed and one mag. MT was made aware of this from multiple sources to include both Vans and BPE -- disappointing that they chose to publish that misconception in the SB even after they were told it was false.

FWIW, my narrow deck engine has 9.0:1 compression and dual Slick impulse mags. Obviously nothing in SB#27 wrt the bushing issue.
Rick
Southampton, Ont
 
That's true, but the link was sent to me from the Feds, and the title on the link said "general aviation". Typical Fed way of paper tracking.
Not unusual for the feds. From the IA test guide:
Malfunction or Defect Reports
All malfunctions or defects that come to the attention of the holder of an IA should be reported on FAA Form 8010-4. (Refer to appendix 1, figure 7.) Copies of the self-addressed form are available at all Flight Standards District Offices (FSDOs), easy to fill out and require no postage. Prompt reporting will contribute much toward improving air safety by helping correct unsafe conditions.
On an OBAM aircraft the repairman or A&P doing the condition inspection is performing the function of an IA.
There are other reporting requirements buried around the regs. How many know that an EFIS failure in flight is a reportable event?
While not strictly a reporting requirement, would you tell the FAA if the cylinder head on your engine departed when the engine was at 50% of TBO?
Point being, unexpected failures at low in service times indicate an engineering or manufacturing problem. In the case of these governors, they are type certificated parts, in some cases installed on type to certificated engines. The SB referring to experimental aircraft with electronic ignition and higher compression is bogus on all three items. They are doing the SB on my governor because its serial number is on the SB, but the model number is not, it is on an RV-10, but the engine is certified, with stock compression and mags. Only the Mt prop and the airframe are not type certificated.
 
MT is now finally gathering our actual data. Their past assumptions have been quite wrong, as evidenced by the wording of the SB, among other things.

If you've had a failure, or know someone who has, please send the information, serial number, installation, engine type, failure type, etc, to the following.

[email protected]

This could save lives.
 
Myron, Did MT contact you requesting this information? They have made no effort that I know of so-far to request information about the failure of my governor.
 
MT is now finally gathering our actual data. Their past assumptions have been quite wrong, as evidenced by the wording of the SB, among other things.

If you've had a failure, or know someone who has, please send the information, serial number, installation, engine type, failure type, etc, to the following.

[email protected]

This could save lives.

I read that there is no difference other than clocking between the various MT units. If so then why is only the 860-3 and not the 860-4 in the SB
 
I read that there is no difference other than clocking between the various MT units. If so then why is only the 860-3 and not the 860-4 in the SB

I don't know if MT has a good grip on the situation My 860-5 was listed by serial number under some other model designation. My up-grade was done because of the s/n being listed and because mine is on an RV-10.
 
Joel,

When my first email to MT in Germany went unanswered, I called Peter and asked for a best contact.
He directed me to Martin Albrecht.
I wrote him with my concerns about the verbiage of the SB, especially the part about EI and high comp cylinders. He answered me next day and asked my details which I sent to him. He answered me back asked for the details of those that I was aware of. That's why I made the post for submissions, but personally think that everyone else should send their info if/how they see fit. I'm not even sure how many of us there are.

Send me your email and I'll forward you a copy of all correspondence.
 
I have just been in contact with MT in Germany. I told them that my governor was on the list but I had 8.5:1 pistons and Slick mags. Did I need to comply with the SB? ....... YES.......

I suggested to them that the wording was confusing and they might want to re-issue the SB - no response.
 
Back
Top