Safety Directive SD-00001 for RV-12/12iS - Elevator Trim Servo
 

Van's Aircraft has published RV-12/12iS Safety Directive SD-00001. It includes a simple inspection and modification of trim tab motor units included in RV-12/12iS kits shipped prior to the publication date (May 14, 2020).

Safety Directives are considered mandatory in nature. This safety directive does not immediately ground existing airplanes, but does require a simple inspection before further flight and action to be taken at next annual condition inspection or by a specified time in service. Details are in the document.

Synopsis of what owners need to do:

1. Examine the stabilator trim motor installed in your aircraft and determine which model is installed.
2. Examine the metal shaft on the trim motor to determine if it is bent.
3. If bent, order the replacement trim motor and bushing parts described in the document.
4. If not bent, determine which of two trim motor models is installed.
5. For the older (no longer shipping) model, replace with the new model if time in service is 1000+ hours. You may, of course, replace the unit before that time with the new parts as well. Note that the Ray Allen Company, which manufactures the units, has set up a low-cost exchange program for affected units of the older model. Details are included in the Safety Directive document.
6. For the newer (current) model, order a small and inexpensive bushing kit which MUST be installed before 1000 hours time in service. NOTE that Van's STRONGLY encourages installation now or at their next annual condition inspection since it is a simple, inexpensive and safety-related change.

Optional Parts Order Issue
 

FYI... The online parts store order search fails for the optional F-1287A-1 (Servo Tray) and BAG 2670

While I agree that the D-Sub connector is a step up from the mini-molex, Steinair has the best, low-cost solution here Simple Trim Servo Connection with D-sub pins.

I've used it several times and truly applaud the adherence to the KISS principle.

That aside....wow, an SD from Van's... I've already contacted the Ray Allen Company for exchange.

Thank you Van's Aircraft for your excellent support and research to develop and improve what I personally hold as the finest aircraft build kits.

This has been fixed. Thanks for the heads-up.

By the shaft on the trim motor, do you mean the square shaft or the threaded portion at the end of the shaft?

Ignore my last. I read the bulletin. But it leads me to this question: do you have to remove the threaded nut and clevis to determine if the shaft is bent?

The shaft is the metal portion and is where the bending might occur. See the SD document for detailed description of the issue, and the last page of the document has drawings to reference and aid in identification. If your trim motor has a square, non-metal portion it is likely it the life-limited, original motor and not the current, updated model.

The shaft runs straight out of the box portion of the unit, perpendicular to the side of the box and parallel to the top of the box. I'd recommend examining closely, and we'd recommend you take advantage of the exchange program Ray Allen has set up for those motors and replace it soon, just out of an abundance of caution. The newer motor with the bushing alleviates concern and it's a pretty simple change.

Don?t you just hate those guys that ask a bunch of question before theY read the SB or look at the aircraft. Done both now. I?m good. Ignore my above ?transgressions.

Reading the document, it appears that the "low cost" replacement motor for those of us with the older version is limited to those with bent or timed-out units. Mine, on a not-yet-flying airplane, is neither bent nor timed-out. Is it possible for us to get the $90 deal?

Jerre

Good question, thanks for asking. I am told that if you have the older model trim motor on an RV-12/12iS, you can contact Ray Allen Company and ask to arrange the exchange, regardless of condition or hours in service.

Just as a matter of interest I'll post some pictures of three servos. These are all the original life limited servos.

Looks Ok ~580 hrs


Looks OK ~300 hrs


Looks bent ~800 hrs

Tony -

Is servo with bent threaded rod yours? Any idea how it got bent? Manhandling stabilator or trim tab?

Would be best to remove and further examine, and then send to Ray Allen for an exchange and so they can take a close look at it.

Not mine. I do know the completed fuselage for this airplane was shipped across the country. The stab wasn't mounted but the servo and pushrod may have been. Could have been manhandled, but no way to know for sure. Otherwise, the airplane was always hangared and well maintained.

Yes, this one will be removed and sent to Ray Allen for review and replacement.

BTW, if your servo is like these with the rectangular actuator, you can slip a wire gauge like a spark plug gauge between the jam nut and the actuator which will help determine any bend. The gap is about .025 or a little wider.

Thank you so much, Tony, for the the photos as examples.

Have any of you tried to make this mod yet? Page 09, step 1 of the latest revision of KAI 11iS/U dated 5/12/20 has you adjust the rod end bearing so the pivot arm length is 16.0?. This dimension was 16-11/16? in the prior revision. The problem I?m having is that it is only 16? from the pivot point to the end of the F-1287F threaded insert for the rod end bearing. So there?s no way to achieve that dimension with the rod end bearing attached. And the part number for the AST push rod has not changed between revisions - still F-1287E.

What am I missing here?

And with about 18 hours on the hobbs, my threaded servo arm was ALREADY bent!!!

Anyone looked at this yet?

Ok - per my previous post, I just noticed an inconsistency... The metric dimension shown is 42.39 cm, which is 16-11/16?. So, one is wrong. I?m guessing which one it is, but not sure why the 16-11/16? dimension was changed.

Scott, can you please confirm?

We will check on that dimension when back in the office - thanks for the note.

Can you please send photos of your bent servo rod to support@vansaircraft.com? Would be interested in seeing yours. Thanks!

Done. And here are photos for any of you that might be interested.

https://www.dropbox.com/s/n6v0mj4drk...51.26.jpg?dl=0

https://www.dropbox.com/s/5tsatcclfi...53.30.jpg?dl=0

Thank you for posting those.

If I may make a point here: To state it plainly and simply, this is exactly why we published the Service Directive. The photos show a pre-failure condition. It's not possible to say how long the unit might take to fail, nor is it possible to say why your servo is in this condition, but this condition is exactly what was predicted and is the first step in the potential series of failure events that caused us to decide to take action. In the safety and risk management world, we call your investigation and discovery a success - It's the SD process working as a preventative measure.

In case people don't take these notifications seriously, this is a great example of why it's important to stay up to date on your service notifications (for any airplane type, not just ours). I'm posting Bob's photos inline here just to make them easier for folks to see. They are good visual examples.

I have looked at your pictures. Your servo and bracket appear clean and maybe lowTT.

How many hours on the airframe?

Any idea how servo rod got bent? Rough ground handling perhaps?

Yes, low TT - about 18 hours. Too bad this SD didn't come out a couple of months earlier, as it would provide more data to analyze this issue. Unfortunately, early April I disassembled the plane for painting. I picked-up the actuator assy. from the painter yesterday to address the SD since it was apart. This was how I found it when I picked it up. So, I can not confirm if it was this way when I removed it from the aircraft. For that matter, this was so discrete of a discrepancy that, for all I know, this could have been bent the day I installed it. Face it, it's been sitting around over two years waiting to be installed, and I could have even bent it day one when I snugged up the jam nut. I just can't say.

I am PRETTY sure the pivot point wasn't contacting the bottom of the tail fairing and that my hole was large enough. And I can guarantee the AST dimensions specified in the PAP were right within range before first flight. Again, this was so discrete of an issue that even if I was doing an inspection it's very likely I would have missed it.

So, yes, it could have been that way from day one, but I believe the take away from this discussion is that it's an issue that can occur.

I read SD 00001 and pulled tail cone fairings off to inspect. My threaded shaft is perfectly straight at 536TT. Early-on I added a 2nd jam nut to lock the threaded shaft to the square servo actuator. So, I will following the SD and monitor shaft for straightness thru 1000 hours of operation.

I'm wondering if threads are rolled or cut? AN hardware uses rolled threads to prevent stress concentration.

Jim, I know you weren?t the original builder, but see step 2 on page 8 of the original KAI section 11.

https://www.dropbox.com/s/jvj8ysixx3...ttach.pdf?dl=0

This step covers adjusting the aft end of the servo push rod. You?ve got a lot more thread exposed between the rod end yoke and the plastic shoulder of the servo drive rod than I, so would expect yours to be more prone to bending. But the kinematics of that appear to indicate that your pivot point would not drop as low as mine when the rod was fully retracted, thus be less likely to bottom out on the tail fairing than mine. Making me wonder now if I was in fact contacting the bottom of the fairing? Just another observation. I?ll certainly be very watchful of this area when the plane is reassembled.

Yes, I'm aware of KAI section 11. I elected to add the 2nd jam nut to prevent rotation, vibration, and working of thread in the square actuator. I never run servo to limits - so no jamming at control stops. I have checked trim function apprx 50% more travel up/dwn than used in flight.

I'll keep "tab" on the tab until 1000TT... :D

When I looked from the side it appears to be not bent.
Took it off and WOW it is really bent
166 hrs


https://www.flickr.com/photos/185605.../shares/4b6a0y
https://www.flickr.com/photos/185605.../shares/y235GN

Safety Directive SD-00001
 

I received my new servo from Ray Allen about a week ago. It was then that I learned I needed to order some parts from Van's also.

I got my parts from Vans today. New tray, F-1287A-1, Bag 2670, and another Bag with the AN315-3R and the Bush-BS 188X 313Xv222 in it. I did not receive any rivets. The new tray has doublers that have to be separated and deburred and then riveted onto the main body of the tray. It seems to me that rivets should have been supplied. I also did not get the rubber gromet that protects the wires from the servo when they go throw the tray. I know there is one on my old tray, but I expected a new one for the new setup. Did anyone get a gromett?

Has anyone else received these items from Van's? If so, did you receive rivets?

Thanks.

John

No bushings or rivets are provided. Apparently you?re expected to reuse the bushings. And since you?re not the builder, guess you don?t have LP4-3 rivets. Van?s approves the use of solid rivets in place of blind rivets. I actually used solid rivets when I rebuilt mine. You might find someone on your field that has some solid rivets.

Hello John,
My order from Ray Allen and Vans was exactly like yours. I wanted to change the plug from the micro molex to the D-sub style so the Service Directive identified the bag needed and the tray replacement due to the fixture on the side that holds the D-sub.
I too checked out the parts and would have liked, and paid for, the plastic grommet that holds the electrical from the servo to the plug. Also the two bushings on the pivot points of the new tray.
Once I get the original parts off, 412 hrs, I will inspect the parts I will need to transfer and determine whether I need to order those parts too.
Now the rivets for me was no issue as I had plenty available, and used solid rivets like Bob Y. I can see where the new tray would need those rivets to complete and supplying the 4 needed makes sense. IMHO

Maybe someone (funflying) could make a short bill of material for the Van?s parts to order for complete new rebuild ? lower bushings, grommet, rivets, etc. so everybody doesn?t have to do their own searching.

One of the items Greg didn?t mention in his initial posting are the terminals for the servo leads. If one doesn?t upgrade to the new D-sub connectors, you?ll need another set of terminals to attach to the new servo leads - if you intend to reuse the existing connector. Guess the other option would be to cut the leads from the old connector long and splice them to the new servo leads so you could reuse the existing one. Just depends on how far one wants to take the replacement.

Safety Directive SD-00001
 

Jim had a good idea about a parts list. If you don't want to reuse the bushings and grommet, you will need to order 2 Bushing TFI-0304-04, 1 grommet SB187-2, and 4 LP4-3 rivets. I have not replaced mine yet, but from looking at the drawings that looks like the additional parts needed. I am planning on reusing those parts, bushings and grommet.

Thanks for the suggestion Jim and to John for looking up the parts and their numbers. And good caught Bob about the connectors for the new servo.

I plan to order the pivot bushings and grommet since I?m replacing the servo, tray, and plug. Thanks again all.

Bag 2670
 

Just received servo tray and bag 2670 trim servo retrofit to replace my old trim servo. The only parts in bag 2670 are d-sub pins and connector for new style tray. I guess I missed where you have to order required bushing and nut separately. I assumed all the parts needed would be in a bag labeled trim servo retrofit. Guess that’s what I get for assuming!

Safety Directive SD-00001
 

And this is a suggestion to Vans. Why not have a bag with all the parts needed to replace the tray, including rivets, bushings, grommett, etc. On other Service Bulletins, the kit to comply includes all parts. Why not treat this one the same way?

I also assumed the plastic bushings and small snap bushing for the wires would be in bag 2670. They are not. I broke one of the old pivot bushings trying to get it out of the old tray so had to send off another order to Van's for small parts.
Here's a couple of other tips.

Someone mentioned reusing those U shaped reinforcements used on the old servo. They won't fit the new servo. The new servo is quite a bit larger.


You can reuse 4 of the old screws to mount the servo but they are a little long. I don't think that matters.


I used this wire diagram from the iS wire diagrams to organize the wiring.

My older airplane harness and old servo wiring had two white wires for UP and DN power and the latest harnesses have a white and black so you can't get the UP/DN wires backwards. The newer airplane harness also has the D-sub male connector already on the airplane harness. Those of us with the old harness have to install the male D-sub pins.

I crimp them (see Stein videos) although I guess you can solder them as well.

I seem to remember from the Dynon auto-trim setup with the AP-knobs panel you could switch this function in the software if you got them backwards. I could be wrong on that. I didn't get that far today since I quit to order the pivot bushings.
I did temporarily hook up the servo motor to see if the cockpit switch would run the servo and if the trim widget on the EMS would track it.


Everything seems to be working, just need to do the trim calibration when I get those pivot bushings and put everything back together.

Yeah, not knowing what was going to be in the 2670 bag and then researching the parts and wiring diagrams was a pain. There were 3 different connector styles used on the trim servo wiring over the years, spades, molex, and D-sub.

Ray Allen was a pleasure to work with. The new servo is shipped quickly. The cost will be the $90, but you pay $219 until you return the old servo for the core charge credit. My old servo is already on the way.:)

Ray Allen
 

Decided to go ahead & replace the trim servo assembly that hasn't even flown yet. Looked over the latest KAI and ordered the following from Van's last night :

(1) F-1287A-1 Servo Tray

(1) BAG 2670 (hoping all the DSUB plugs, pins, sockets are in it, anybody know exactly what's in it?)

(2) TFI-0304-04 Tray BUSHINGs (in case I booger up the old ones in original tray - and can always make better ones the second time around ;)

(1) SB187-2 Snap BUSHING (again, in case I booger up the old one that servo wires run thru)

(1) AT6-058X5/16X4 Al Tube to cut to length of the two bushings (again, I want to try to make even better ones this time)

(1) AN315-3R Jam Nut (just in case)

Spoke with Gary at Ray Allen today (on way to Post Office with old servo in hand) to confirm a couple of things and work thru the deal.
He said it's fine to mail the old servo in a simple "bubble wrap" envelope. Packaging isn't critical, they just what to examine & keep track of the returns.
Wanting to save a few days, I went ahead and ordered the replacement actuator on credit card and they'll take care of the math ($219-$90 plus shipping) when the old one arrives.
Very knowledgeable & friendly service and he said their "company plane" is an RV-12 so he knew exactly what I was trying to articulate.

Bag 2670
 

1 female d-sub
1 male d-sub
6 female d-sub pins ( 1 extra )
6 male d-sub pins ( ditto)
2 standoff nuts
2 4-40 allen screws
2 4-40 all metal locknuts
a d-sub pin tool

The bag parts are just for the d-sub installation. My nomenclature may not be perfect on these parts but you'll get the idea.
Those little metal locknuts are really tiny. I had no US socket or wrench that small but found a 4.5mm socket fit them perfectly.

There is a use for that extra jam nut (it's not in the bag) - see Section 11iS/U-07 Fig. 3

In the install directions and pic it does not show the use of the jam nut anymore,but says to order one which i did,but I dont see it being used anymore?
Comments on this?
Thanks,