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SB-00023 published: RV-12/12iS Engine Mount Standoff Inspection/Replacement

greghughespdx

Well Known Member
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Van's has published Service Bulletin SB-00023, which guides affected RV-12/12iS aircraft owners (as listed in the doc) to inspect the engine mount standoff weldment on affected aircraft for cracks. Van's is aware of two RV-12/12iS aircraft on which these cracks have been observed. Inspection can be completed with the top cowl removed using a small inspection mirror.

  • If cracks are found, do not fly the aircraft. Replace the stand-off with the new version part.
  • If you do not find cracks, you may continue to fly and need to inspect periodically at least every 100 hours. Details are contained in the service bulletin document.
 
Van's has published Service Bulletin SB-00023, which guides affected RV-12/12iS aircraft owners (as listed in the doc) to inspect the engine mount standoff weldment on affected aircraft for cracks. Van's is aware of two RV-12/12iS aircraft on which these cracks have been observed. Inspection can be completed with the top cowl removed using a small inspection mirror.

  • If cracks are found, do not fly the aircraft. Replace the stand-off with the new version part.
  • If you do not find cracks, you may continue to fly and need to inspect periodically at least every 100 hours. Details are contained in the service bulletin document.

Wondering if you can share how many hours on the two aircraft. I just ordered the new standoff engine mount, did not do the inspection yet, but my annual is coming so I will just replace it whether the inspection is good or bad. The mount is $280.00 incase others want to know.
 
Ugh. Does it stop? gear leg, Nose Fork, Exhaust, Trim motor, prop balance, throttle springs, and now these mount standoffs.

Don’t get me wrong, I’m very grateful that Van’s is proactive and ‘on it’. Just feel like there are so many SB’s on an otherwise excellent airplane.
 
Wondering if you can share how many hours on the two aircraft. I just ordered the new standoff engine mount, did not do the inspection yet, but my annual is coming so I will just replace it whether the inspection is good or bad. The mount is $280.00 incase others want to know.

Around 900 hours on one of the aircraft. I will have to see whether or not I can find out how many hours on the other one.

Owner's choice on proactive replacement. It's an easy changeout. I would certainly inspect regularly of course, and I inspect under the cowl much more frequently than every 100 hours already in the normal course of maintenance. I mean, oil changes require removing the top cowl at least twice every 100 hours (more often for the one I deal with) and I tend to have the top cowl off even more frequently than that just to take a look and make sure everything's as it should be.
 
Around 900 hours on one of the aircraft. I will have to see whether or not I can find out how many hours on the other one.

Owner's choice on proactive replacement. It's an easy changeout. I would certainly inspect regularly of course, and I inspect under the cowl much more frequently than every 100 hours already in the normal course of maintenance. I mean, oil changes require removing the top cowl at least twice every 100 hours (more often for the one I deal with) and I tend to have the top cowl off even more frequently than that just to take a look and make sure everything's as it should be.

Ya going to bit the bullet on this one. A engine mount is nothing to mess around with. Can you tell us, is there a design change in the original WD-01221 ver the new WD-01221-1? If so what is the difference?
 
I have had engine mount cracks in my Cherokee and one other home built. I would never trivialize this, but there are enough redundant load paths to protect you until inspection. Obviously if you find cracks you should ground the aircraft until you fix them.
 
top cowl only

Greg you must have long arms to change oil with just the top cowl off. Two wrenches under the tank to remove the plug, then catch the plug and hold a container for the oil, and thats not counting holding the bottle for the oil test sample. An "easy changeout", I believe it took me two hours just to install the two bolts through the firewall and that was with no engine and cables in the way.
 
I'm just about ready to have an AW certification.. so I'll probably inspect my 0-time engine mount and make the log entry. Replace it in a year.

I have to think that if it was 2 planes out of .. 1000?, this isn't something to worry too much about. I don't like the idea of going over an important structure with a magnifying glass every time the cowl is open (for peace of mind).. so I'll probably squirrel a little money away each month and just replace it.

I'm sure the prop balancing SB will help out on wear in this area.
 
Performed the inspection last night. At just over 50 hours on the hobbs I wasn't expecting to find any issues. Will inspect again at next condition inspection and probably go ahead and replace. Aircraft will have a prop balance in the near future.
 
Glad there is tremendous oversight by Van's but (sarcastically) I'm now going to need a much larger binder to organize all the Van's SBs on the 12. Is there a part we haven't reinspected or replaced over the last five years?
 
Glad there is tremendous oversight by Van's but (sarcastically) I'm now going to need a much larger binder to organize all the Van's SBs on the 12. Is there a part we haven't reinspected or replaced over the last five years?

As a previous C-177RG owner, and current half owner of a Cirrus SR-22, I would like to offer my point of view that the number of SB's we have received from Vans are very in small number and very inexpensive compared to what I am otherwise used to. I believe that owners of other certificated aircraft would probably say something similar.

The fact of the matter is that aircraft are designed with numerous mutually incompatible goals-- be light, be strong, be fast to build, be fast to fly, be economical, be maintenance free, and—above all—be safe. It's simply not possible to achieve all of these. Engineers make their best calculations and estimates. Professional engineers, such as are at Vans, then monitor their products' peformance in the real world and modify them (sometimes with service bulletins) as reality dictates.

This is simply the cost of owning an aircraft. The RV-12(iS) is a very inexpensive aircraft. Period.

If you'd like some numbers on cost of ownership of my SR-22 or of my previous C-177RG, just PM and I'll be happy to oblige.
 
Reasons the RV-12 may have more SBs.

My question is are there more SB's for the Rv-12 than the other RV models?

The RV-12 is the only RV model designed to a "Standard". (ASTM)

And, in the case of the S-LSA, it is also the only RV model that may be used commercially as in flight schools.
 
The RV-12 is the only RV model designed to a "Standard". (ASTM)

Compare the number of bulletins from the RV-12 and -14. The -14 has just a handful. Its not that the factory designed the perfect aircraft in the -14.. its just that (I think), the factory doesn't have to issue letters for every single screw or wire that was incorrect in the KAI, etc. A bunch of letters are ones that "allow installation of".. ok lets not even count those.

Most of the expensive bulletins are for important things though.. nose gear collapse.. engine falling off... Even huge certificated mfgs have problems that need to be fixed after the aircraft has left the factory.. and those are even more expensive repairs just due to paperwork and needing an A&P.

Lets not forget that most of us here have an EXPERIMENTAL aircraft and these are not Airworthiness Directives.
 
Compare the number of bulletins from the RV-12 and -14. The -14 has just a handful. Its not that the factory designed the perfect aircraft in the -14.. its just that (I think), the factory doesn't have to issue letters for every single screw or wire that was incorrect in the KAI, etc. A bunch of letters are ones that "allow installation of".. ok lets not even count those.

Most of the expensive bulletins are for important things though.. nose gear collapse.. engine falling off... Even huge certificated mfgs have problems that need to be fixed after the aircraft has left the factory.. and those are even more expensive repairs just due to paperwork and needing an A&P.

Lets not forget that most of us here have an EXPERIMENTAL aircraft and these are not Airworthiness Directives.

In the Light Sport world SB's are equivalent to AD's in the Certificated world.
 
In the Light Sport world SB's are equivalent to AD's in the Certificated world.

Mel, can you update us on this? As of 2015, the only thing that was legally mandatory were Safety Directives (SD) for S-LSA aircraft. There are 3 SDs for RV-12 and 2 for RV12iS. SB's were optional, but in either case, only certain certificated persons could perform maintenance on S-LSA (as specified in the SB/SD).

There was supposed to be some rule change that changed or clarified what was legally mandatory. To what, I'm still trying to research.

Are SB's now also mandatory for S-LSA? Are E-LSA completely free from legal mandates, even from aircraft or powerplant SDs?
 
Greg you must have long arms to change oil with just the top cowl off. Two wrenches under the tank to remove the plug, then catch the plug and hold a container for the oil, and thats not counting holding the bottle for the oil test sample.
I installed a quarter-turn quick drain valve on my oil tank. I can reach it to attach a hose to it by reaching up through the openings at the back of the lower cowl. I can also remove the oil filter and magnetic plug with the lower cowl still attached. It is a much easier process to change the oil that way. FWIW.
 
Greg you must have long arms to change oil with just the top cowl off. Two wrenches under the tank to remove the plug, then catch the plug and hold a container for the oil, and thats not counting holding the bottle for the oil test sample. An "easy changeout", I believe it took me two hours just to install the two bolts through the firewall and that was with no engine and cables in the way.

I think you totally missed Greg's point.....

I doubt anyone changes the oil by removing only the bottom cowl, so that means the top cowl is off at every oil change (what he likely meant).
That means at every oil change there is an easy opportunity to inspect the engine mount standoff.

Secondary comment.... All our aircraft at Van's have quick drain valves for doing oil changes but those are utilized for the convenience of not haveing to remove and then reseal on installation, a drain plug.

We do not at all endorse (in fact we discourage) doing oil changes with part of the cowl still installed.
Stuff breaks on airplanes. A lot of that stuff can cause a serious safety issue. Taking a good look over the entire engine installation every 50 hrs or so is a very good idea.
 
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"Taking a good look over the entire engine installation every 50 hrs or so is a very good idea."

And I don't disagree.

I can count on one finger the times that I have done an annual inspection that had an additional 50 hours since the previous one. I have also changed oil that had no more than 7 hours on it. My oil changes are done by calendar, not hours.

Everyone's situation is different. Some of us rack up a lot of hours, and some of us don't. I take a deep-dive look at any part of the airplane that gets exposed throughout the year, which is often enough with service bulletins and other maintenance jobs that crop up. If it has been awhile when an oil change comes due, I strip it down to take a look.

That said, I don't feel a compelling need to prolong routine jobs if I don't believe that the current situation warrants it.

I'm comfortable with making those decisions for myself. It's why I have an Experimental.
 
I installed a quarter-turn quick drain valve on my oil tank. I can reach it to attach a hose to it by reaching up through the openings at the back of the lower cowl. I can also remove the oil filter and magnetic plug with the lower cowl still attached. It is a much easier process to change the oil that way. FWIW.

"Taking a good look over the entire engine installation every 50 hrs or so is a very good idea."

And I don't disagree.

I can count on one finger the times that I have done an annual inspection that had an additional 50 hours since the previous one. I have also changed oil that had no more than 7 hours on it. My oil changes are done by calendar, not hours.

Everyone's situation is different. Some of us rack up a lot of hours, and some of us don't. I take a deep-dive look at any part of the airplane that gets exposed throughout the year, which is often enough with service bulletins and other maintenance jobs that crop up. If it has been awhile when an oil change comes due, I strip it down to take a look.

That said, I don't feel a compelling need to prolong routine jobs if I don't believe that the current situation warrants it.

I'm comfortable with making those decisions for myself. It's why I have an Experimental.


Your first post clearly indicates you can do an oil change without removing the bottom cowl, so I guess what you are saying in the second post is that you do at least one during the year at far fewer hrs than then normal change interval and for that one you don’t remove the bottom cowl?

Fair enough, but based on some of the fwf issues I have seen on aircraft over the years, My recommendation is that people use every opportunity available to do an inspection. It takes maybe 5-6 more minutes to remove the bottom cowl on most RV’s.
 
Gosh, I'm getting tired of throwing out parts that have exactly ZERO flight time.

I'm in the middle of installing the engine so it seems prudent to stop, take it off and make this replacement just as I did with the gear leg last year. As someone upstream noted, the engine mount is nothing to mess around with.

Two steps forward....1 back.

Also, can we get some details on the design change?
 
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Gosh, I'm getting tired of throwing out parts that have exactly ZERO flight time.

I'm in the middle of installing the engine so it seems prudent to stop, take it off and make this replacement just as I did with the gear leg last year. As someone upstream noted, the engine mount is nothing to mess around with.

Two steps forward....1 back.

Also, can we get some details on the design change?

Bob, you don't need to remove the engine and mount to change the nose gear leg or engine mount truss.
 
The timing on these things has been comparatively fortuitous. I did the nose gear leg last winter before I got the powerplant kit. Easy peasy (except on the wallet, of course)

Yes, looking closer at the steps (I saw the engine hoist earlier which is why I thought it'd be more complex than it is), I see that I can just unload the weight, pull the bolts, remove, replace, insert bolts, torque, and be done.

Shouldn't be too hard.
 
I have asked this question before with no answer: why are all these part failures happening in the field, but not on the original Vans RV-12? Leads me to believe pilot technique is causing many of these failures leading to fleet replacements. Case in point: I have 1040 hours and over 8 years on my 12 with the same nose tire that still looks like new tread. Why would I expect a nose gear leg failure. I never found loose rivets on the engine mount, I never had wing skin cracks, my prop hub never cracked, my trim servo isn’t bent and I have never seen cracks on my stabilator spar. Seems like some of this stuff is overkill.
 
It may seem like overkill and you may be right. Maybe lots of these issues are the result of rough handling of a plane that’s lightly built for a reason, but at least when Vans become aware of a problem they obviously take it seriously and we end up with an improved aircraft. If they just ignored problems, even apparently minor ones, they’d soon be out of business.
 
The 12 is the only Van's model that can be used for flight schools, etc., it's the only model in which the data plate lists Van's as the builder. And it's the only model -- AFAIK -- in which the kit includes everything. Also, it's the only model that can be purchased as an SLSA.So it stands to logical reason that there would be more SBs and SAs. How else would the information be relayed in an environment in which this model has more widespread missions than any other Van's model?

If you're building as an EAB, and don't wish to make any changes, then the SBs and SAs don't really concern you, you can just ignore it. And obviously if you do an inspection and don't see cracks, come back in 100 hours. There's no real reason anyone should feel particularly put upon by the parameters of this service bulletin. Given the flexibility you have as a builder or owner, how can that possibly be considered overkill? The SB is basically telling you merely to look for cracks, which, of course, you should be doing anyway.

The underlying issue here, though, isn't getting talked about and it should be.

This line is significant:

Note that primary potential causes of vibration on the RV-12/12iS are carburetor sync and propeller balance issues.


The SB underscores the need to control vibration in an RV-12. That's not something that should be ignored regardless of whether you choose to install the new mount.
 
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I have asked this question before with no answer: why are all these part failures happening in the field, but not on the original Vans RV-12? Leads me to believe pilot technique is causing many of these failures leading to fleet replacements. Case in point: I have 1040 hours and over 8 years on my 12 with the same nose tire that still looks like new tread. Why would I expect a nose gear leg failure. I never found loose rivets on the engine mount, I never had wing skin cracks, my prop hub never cracked, my trim servo isn’t bent and I have never seen cracks on my stabilator spar. Seems like some of this stuff is overkill.

A S-LSA in a flight school, sitting on the tarmac, day and night, without the seat belts latched around the joy stick, in high winds, slamming the stabilator or rudders end to end, is a different environment from most E-LSA owner/ builder or 2nd or 3rd owner,where the owner or builder hangars their plane, when not flying.

Add in students learning to fly, and learning to land, not always being the most gentle, having landings that might stretch the definition of a "firm" landing with slightly too low an airspeed approach, due to inexperience with very minor throttle adjustments, and it's a rough environment for the equipment and could induce failures.

It's a rental, and like a rental car, there's no pride in ownership, nor treating the equipment like they would their own. There could be a tendency towards borderline abuse, due to lack of experience of student pilots.

Myself, personally, I don't think I would ever buy a Legacy RV-12 S-LSA used, from a flight school, much like I would never buy a used car from a Rental agency or off of lease. It was a business asset and a tool, used to make money. As a general contractor, I sold my used tools because it was time for newer, more productive tools. Too much time lost taking it into the shop for repairs and down time, no longer made it as profitable as a new tool. Craigslist time!
 
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The 12 is the only Van's model that can be used for flight schools, etc., it's the only model in which the data plate lists Van's as the builder. And it's the only model -- AFAIK -- in which the kit includes everything. Also, it's the only model that can be purchased as an SLSA.So it stands to logical reason that there would be more SBs and SAs. How else would the information be relayed in an environment in which this model has more widespread missions than any other Van's model?

If you're building as an EAB, and don't wish to make any changes, then the SBs and SAs don't really concern you, you can just ignore it. And obviously if you do an inspection and don't see cracks, come back in 100 hours. There's no real reason anyone should feel particularly put upon by the parameters of this service bulletin. Given the flexibility you have as a builder or owner, how can that possibly be considered overkill? The SB is basically telling you merely to look for cracks, which, of course, you should be doing anyway.

The underlying issue here, though, isn't getting talked about and it should be.

This line is significant:

Note that primary potential causes of vibration on the RV-12/12iS are carburetor sync and propeller balance issues.


The SB underscores the need to control vibration in an RV-12. That's not something that should be ignored regardless of whether you choose to install the new mount.

Also add in a Worn Clutch on the gearbox, or clutch dogs worn or Bellvue washers losing tension, and needing replacement or reshimming, as well as Carburetor rebuilds.
 
I think it’s great we get info on field failures. The problem is that in many cases there just isn’t enough info from the field to do a thorough root cause of failure. The original nose leg is a good example. I understand the new FEA identified the accident aircraft failure location as the weakest point, but the leg passed the LSA drop tests. If the drop tests are truly representative of the anticipated hard landings then it seems the accident aircraft must have gone beyond the design limits. If you take anything beyond what it is designed to do you are in unknown territory.

I bought the nose leg (haven’t received it yet) and I will install it, but I’m getting very skeptical about all these replacement part SBs.
 
nut.jpg


Not the ones that attach the standoff to the engine mount and isolators. They are all metal locknuts.
 
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Question: Should the locknuts be reused or replaced when swapping this out?

nut.jpg


Not the ones that attach the standoff to the engine mount and isolators. They are all metal locknuts.

As a general guideline, if a self locking not can not be turned by hand once fully engaged on a fastener, it is acceptable to reuse.

Nylock style nuts are a lot more likely to lose prevailing torque after a few installations.
All steel self locking nut are generally good for many uses but should be checked each time to be sure.
 
Not the ones that attach the standoff to the engine mount and isolators. They are all metal locknuts.

Apparently another difference between the ULS and the iS, as they are Castellated Nuts on the iS. Guess we need to be more specific when replying due some of the more subtle differences.
 
What is the difference between the new WD-01221-1 and the original design?

The following from Van's support line: "Visually the parts should look very much the same, the difference is the wall thickness of the cross tube has been increased form .049 up to .083, almost double."
 
The following from Van's support line: "Visually the parts should look very much the same, the difference is the wall thickness of the cross tube has been increased form .049 up to .083, almost double."

Many thanks John.
 
I have one

Just inspected mine, and found a crack just where shown on the drawing. The powder coat had a hairline crack around 270 degrees of the tube. I scraped away a small portion of the coating and seemed like I could see the underlying crack. After applying dye penetrant it seems to be a crack for sure.

600 or so hours, no "hard" landings or other such events likely to be signifiicant.
 
Just inspected mine, and found a crack just where shown on the drawing. The powder coat had a hairline crack around 270 degrees of the tube. I scraped away a small portion of the coating and seemed like I could see the underlying crack. After applying dye penetrant it seems to be a crack for sure.

600 or so hours, no "hard" landings or other such events likely to be signifiicant.

Was your prop balanced? Just wondering if that may be a contributing factor. Not that one sample would prove much one way or the other but perhaps worth asking the question.
 
Folks,

FYI we published a minor revision to the SB-00023 document today in which we specifically call out the need to support the tail when lifting on the engine (tail stand or padded sawhorse under a bulkhead, etc), just in case someone would not think ahead of time to properly support the tail end of the aircraft while lifting on the nose. No one wants an unintentional tail strike, including in the shop.

And to answer the obvious question: No, this was not done in response to a specific incident. :)

Thx.
 
Any other cracks reported?

To answer your question, we did have some engine vibration last year around 3500rpm.

We overhauled the gearbox, rebalanced the carbs, and balanced the prop. We still get a little lumpiness at 3500rpm. None of this may be significant, but we won't know until we replace the broken standoff.
 
To answer your question, we did have some engine vibration last year around 3500rpm.

We overhauled the gearbox, rebalanced the carbs, and balanced the prop. We still get a little lumpiness at 3500rpm. None of this may be significant, but we won't know until we replace the broken standoff.

When is the last time you inspected and rebuilt the Carburetors, including the main jets? The vibrations can cause the jets and needle valves to wear, and need replacement. Some trouble shooting ideas here: https://www.rotax-owner.com/en/general-tech-discussion/4252-schedule-for-carburetor-overhaul
 
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As has been stated many times… because the Rotax912 utilizes two individual carburetors, it is virtually impossible to have equal power balance L-R at all power settings. We synchronize throttle position with manifold pressure at idle, and off-idle, where uneven power pulses are damaging to the gearbox. Near wide-open throttle at cruise is very near synchronization by virtue of massive airflow and fuel atomization only thru the main jet. It is the mid-range that is problematic and not adjustable. Some carbs will be closely synchronized in mid-range, but it is really just luck of the draw.
 
When is the last time you inspected and rebuilt the Carburetors, including the main jets? The vibrations can cause the jets and needle valves to wear, and need replacement. Some trouble shooting ideas here: https://www.rotax-owner.com/en/general-tech-discussion/4252-schedule-for-carburetor-overhaul

I didn't mention it but, amongst all the other work done last year, I also serviced the carbs and had the mags overhauled.

I cannot believe Vans is out of stock on the very day they announced the replacement part, claiming they had stuff in stock. Surely these should have been prioritised to folk with flying aircraft. I'm not happy having to wait best part of two months :-(


I don't suppose anyone has ordered one from stock which they don't need for two months?

Cheers...Keith
 
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