Doing Service Bulletin 18-02-02 Part 1 of 3

Back in February Van’s Aircraft issued Service Bulletin 18-02-02 involving possible cracks forming on the horizontal stabilator’s front spar. It appears a very tiny number of RV-12’s have developed stress cracks where the bearing bracket mounts onto the stabilator’s front spar. (Some believe the cracks are forming from the common practice of using the seatbelt to lock the control stick full aft which places the stabilator on the stop so it does not move and bang into the stops on windy days. As a result, some believe the energy from strong winds (or passing airplanes) is transferred directly into the spar at the nutplates for the stabilator mounting bolts causing the stress fractures over time).The service bulletin calls for removal of the stabilator and associated hinge brackets for an inspection of the front spar for cracking … if no cracks are found, the inspection is to be performed every 100 hours or annual inspection. If cracks are found, the service bulletin is to be installed immediately.


Just to be clear, NO cracks were developing on the DOG Aviation RV-12 … however, decided while the RV-12 is down for a condition inspection may just as well go ahead and install Service Bulletin 18-02-02 now and be done with it. I’m here to tell you getting the stabilator off and reinstalled just to inspect every 100 hours is not a piece of cake. As such, decided may just as well go ahead and install the service bulletin now as a preemptive strike and have one less thing to worry about. Plus, doing the work now means all the new parts will be on the stabilator when the RV-12 gets painted this coming spring.


Installing the stabilator service bulletin involves removing the inboard and outboard hinge brackets and throwing them away. The old hinge brackets are replaced with a new hinge brackets that sit on a new doubler plate … in addition, supporting parts are added that create a box around the hinge brackets which tie into the stabilator’s skins and spar. There are also additional doubler plates riveted under the stabilator horns for the control cables. This is not a 10 minute job … plan on at least a full day’s work to install this service bulletin.


Prior to attempting this service bulletin, you will absolutely want to procure a 12” long #30 drill bit to easily access some of the rivets that need to be removed and for drilling some of the new rivet holes. (As a side note, builders/owners may want to also consider replacing all the bolts that screw into nutplates with new bolts. In this case that involves replacing 16 AN3-4A bolts and 2 AN4-12A bolts. Is this truly necessary? Probably not. But I have it on very good authority that “ideally” bolts that screw into nutplates should be replaced after each use. Small bolts like these are really inexpensive, so during final assembly, the DOG Aviation RV-12 will receive new hardware at those locations on the stabilator where bolts screw into nutplates).


 Some of the parts included with the service bulletin need to be separated on the band saw … after doing that all the parts were dressed on the Scotch-Brite wheel to remove burrs and smooth edges then prepped for priming. Because my Akzo epoxy primer is now way out of date and changing color, decided to use SEM self-etching primer and place the parts in a hot box for drying.

The parts for the Stabilator service bulletin primed and ready for instillation.

For ease of removal and instillation of the stabilator assembly the RV-12’s tail was lowered by placing the nose gear on blocks so the stabilator was about the same level as the workbench. Before the stabilator can be unbolted from the fuselage a few items need to be removed … starting with the tail cone’s upper and lower faring’s, the pitch trim servo pushrod and of course the upper and lower stabilator cables. Others have reported that the stabilator cables can be removed without unscrewing the adjusting barrels ….. so that was the tact taken. The cables were easily removed by pulling aft on the cables gently and sliding the bolt out. Prior to removing the cables, a piece of safety wire was wrapped around the cable and secured to the tail cone …. Doing this will insure the cable won’t fall into the tail cone if it slips out of the hand. Mike K. gave me a hand removing the stabilator from the tail cone … thanks Mike.

After removing the stabilator cables from the upper and lower stabilator horns, tie wraps were used to help prevent the cables from falling back into the tail cone …. note the safety wire is the insurance policy.


Note: Before discussing the actual instillation of the new parts, fellow RV-12 builders/owners and readers of this Blog should be aware I deviated from the instillation guide in three areas …. I did not drill the control horns per the plans (more on that a couple of paragraphs below), three solid rivets were used on the inboard flanges of the HS-01231B instead of two solid rivets and a pop rivet (more work but done for a consistent look) and lastly because flush rivets were installed on all the DOG Aviation’s RV-12 exterior skins, the rivet holes on the HS-01231C stabilator hinge gussets common to the stabilator’s skins were machine countersunk for flush rivets (99.9 % of builders won’t need to consider this unless, like myself, you used flush rivets on the stabilator’s skins).


OK, let’s get started. The process for the service bulletin begins by making measurements and marking the WD-1207 & 1208 upper and lower stabilator horns to receive six AN426AD3-4 rivets each. The six rivet locations are to be carefully marked and center punched on each stabilator horn. After center punching the horns, the HS-01232 stabilator horn doubler is centered beneath the WD-1207 stabilator horn then match drilled into the HS-1211 spar cap and secured with Clecos.

The HS-01232 doubler is centered under the WD-1207 stabilator horn and between the edges of the spar box and taped in place. Note the center punching for the six holes to be drilled into the WD-1207 horn can be also seen. Also of note, the center punch marks were biased just outboard of the lines to make it a little easier to squeeze the rivets with the pneumatic squeezer (done later).

Prior to drilling, a clamp was used just to make sure the HS-01232 doubler does not move during the drilling process.

Match drilling the #30 holes in the HS-01232 stabilator horn doubler into the HS-1211 spar cap.

Completed match drilling of the HS-01232 stabilator horn doubler into the HS-1211 spar cap.

Here is where I deviated from the plans and why. At this point Van’s would have the builder/owner drill down through the WD-1207 stabilator horn and through the HS-01232 stabilator horn doubler and then into the HS-1211 spar cap. This really bothered me because ultimately the six holes created in the HS-1211 spar cap serve no purpose other than it was easy to do it this way (and admittedly less work). The six holes in the HS-01232 doubler will ultimately receive countersinking for AN426AD3-4 rivets which will be used to attach the HS-01232 doubler to the bottom of the WD-1207 horn leaving the six #40 holes in the HS-1211 spar cap unused  … same applies for the HS-01232 doubler on the other side for the WD-1208 horn.


My solution was to NOT drill the remaining six holes directly into the HS-1211 spar cap … this was accomplished by first removing the WD-1207 and moving it to a drill press, drilling a #50 lead hole at the six center punched rivet locations, then stepping up the six holes to the final size of #40.

Completed drilling of three rivet holes to #50 on one side of the WD-1207 horn … three down three to go.

The newly drilled WD-1207 horn was bolted back in place over the HS-01232 stabilator horn doubler. Next, the six #40 holes in the WD-1207 horn were used as guides to partially drill into the underlying HS-01232 stabilator horn doubler just enough to leave a nice deep dimple but not enough to drill completely through the piece. Tape was placed on the HS-01232 to note correct orientation and the WD-1207 horn was removed so the HS-01232 doubler could be taken over to the drill press and final drilled using the deep dimples as a guide for the #40 drill bit.

Newly drilled WD-1207 horn bolted back in position so the newly drilled #40 holes can be used to match drill the underlying HS-01232 doubler.

Using the #40 holes in the WD-1207 as guides, one can see the HS-01232 doubler was drilled just enough to create nice dimples that can be used to complete the drilling on the drill press.

The HS-01232 doubler with the newly created six holes … note the spar cap in the background came out unscathed without the additional six holes (that would not be used for rivets) had the service bulletin instructions been followed exactly as written.


To complete the work on the WD-1207 the six #40 holes in the HS-01232 doubler need to be machine countersunk from the bottom for AN426AD3-4 rivets. Next the HS-01232 doubler is riveted onto the WD-1207 stabilator horn. To accomplish this task the pneumatic squeezer was outfitted with the little used “no hole yoke” and the WD-1207 stabilator horn was covered with blue tape to prevent scratches.

A “no hole” yoke was used on the pneumatic rivet squeezer to secure the HS-01232 doubler to the bottom of the WD-1207 stabilator horn using AN426AD3-4 rivets.

Completed riveting of the HS-01232 doubler to the WD-1207 stabilator horn.

Test fit of the WD-1207/HS-01232 doubler assembly on the stabilator spar … fits good.

Gee, this was so much fun let’s flip the stabilator over and do it all again for the WD-1208 stabilator horn on the other side using the same process. After riveting the HS-01232 doublers to both the WD-1207 & WD-1208 stabilator horns, both horn assemblies are set aside and will be installed later.


I’m very happy … this portion of the service bulletin turned out great! And with no extra holes in the HS-1211 spar cap. Admittedly, it took more time doing the drilling this way and lots of care needs to be taken to assure proper alignment … just move slowly if considering performing the work the way I did it. Next up is installing the new hinge brackets which will be documented in the next post.

Mr. Sandy Ballast Receives First Passenger Ride In The DOG Aviation RV-12

Due to having done some modifications such as adding the modified “Bender baffle” and moving the voltage regulator onto the baffle … plus, installing interior baggage carpet and padded side panels to the interior I know the weight and balance has changed since the time the first W&B measurements were made.


Because the plan is to do some flight testing with the airplane loaded close to gross weight, felt it prudent to make new weight and balance measurements before blindly trying to test fly the RV-12 near the forward and aft CG (center of gravity) limits. As such, all the fuel was drained from the fuel tank and the airplane was leveled on the scales so new weight measurements could be obtained. For those interested, the procedure for determining weight & balance was covered in the August 10, 2016 post found at the following link.


Performing weight & balance measurements on the RV-12


After taking the new weight measurements, the weight and balance sheets were updated to reflect the changes and per FAA regulations, an updated copy is kept inside the aircraft. Also updated the aircraft maintenance log books as well.


My CG did move forward some as I expected it would from the modifications. As it sits, the DOG aviation RV-12 will hit the forward CG limit when there is only one gallon of fuel left in the tank when I fly solo … and with a 230 pound passenger, the forward CG limit will be hit with 3 gallons of fuel left. So I feel I’m in the sweet spot because I know when the RV-12 gets painted, the CG will move aft … so hitting the forward CG limit after painting should not be an issue when giving rides to most people who are capable of comfortably fitting into the RV-12 cockpit.


Chad (an A&P mechanic that works on lots of airplanes on the field) was nice enough to loan me 230 pounds of sand bags for the test flight …. Thanks Chad!  I borrowed one 50 pound of play sand and three 60 pound bags of tube sand. The plan was to get close to gross weight but not over while keeping near the center of the RV-12’s CG range which is 80.49 inches to 85.39 inches. With myself, 230 pounds of sand, 19 gallons of fuel and no baggage, the takeoff CG was 82.66 inches. Although not perfectly in the center of the CG range 82.66 inches is close enough. In this configuration, the CG will slowly move forward as fuel is burned and at approximately the 3 gallon point the forward CG limit will be met. As such, I plan to fly down to about 5 gallons so as to get close to the forward CG limit and check out the handling. Because the RV-12 is a proven design, I don’t expect any control issues or surprises.


After removing the passenger’s seatback and seat bottom cushion the 50 pound bag of play sand was placed on the passenger seat floor. Because the sand bags have been used quite a bit, some were showings signs of wear … so as an insurance policy, the decision was made to place all the sand bags into trash bags just in case there was an unwanted rupture.

First 50 pound bag of play sand placed into a trash bag and placed on the passenger seat floor.


The next three 60 pound bags of sand are of the tube variety and those were placed upright on the 50 pound bag of sand. This arrangement actually worked out quite well in that the sand bags did not interfere with the flap handle or the ELT mounted on the far right … and more importantly did not interfere with control stick movement. Cargo straps were placed around the bottom of the tube sand bags and fed through the handle for spar pin as an anchoring point to prevent the sand bags from sliding to the left towards the flap handle. A second cargo strap was placed higher up and secured to the fuselage cross brace.

Mr. Sandy Ballast bravely volunteered to become the first passenger to receive a flight in the DOG Aviation RV-12. With the three bags of tube sand positioned two aft and one centered forward there was plenty of clearance between the stick and Mr. Sandy Ballast.


The test flight occurred during a beautiful hot morning. The air was perfectly smooth throughout the flight and even though Mr Sandy Ballast was very quiet during the entire test flight, I think he had a great time as the airplane made tight turns, stalls, and some touch-and-go landings.


There were no surprises during the test flight … the extra weight and warm temperatures (high 80’s) make for a little longer ground roll than when solo. Climb-out was good just not as sporty compared to being solo. Landings were uneventful, but I did notice more brake was required to slow down and the stopping distance was longer than when flying solo. All the things one would expect with a heavy passenger.


The RV-12 is simply a nice flying Light Sport aircraft.

ADS-B In Upgraded To Dynon SV-ADSB-472

Out with the old and in with the new. Even before the first flight the DOG Aviation RV-12 has been outfitted with Dynon’s SV-ADSB-470 an ADS-B In receiver but for reasons explained a few paragraphs below, I’m upgrading to Dynon’s latest ADS-B In solution …. The SV-ADSB-472 ADS-B In receiver.


For non-aviation readers, ADS-B stands for Automatic Dependent Surveillance—Broadcast. The FAA is requiring that by year 2020 all aircraft flying in Class A, B or C controlled airspace be equipped with ADS-B Out … this means (with few exceptions), that any airspace currently requiring an aircraft to be equipped with a Mode C transponder will now require the aircraft to broadcast an ADS-B Out signal.  This is part of the FAA’s broader plan called NextGen … which will require all aircraft flying in the aforementioned airspaces to periodically send an ADS-B Out broadcast containing information about the aircraft, such as identification, current GPS position, altitude, and velocity. It is said that NextGen will allow for more aircraft to be in “the system” because radar will not be needed to see the aircraft … plus, air traffic controllers will know the exact altitude, speed and GPS location of aircraft which should allow tighter spacing of aircraft than is currently possible with a ground based radar air traffic control system.


Of course, when the NextGen year 2020 mandate was announced many years ago, pilots and pilot advocacy  groups howled (and rightfully so) because the ADS-B Out mandate will cost aircraft owners thousands of dollars to retrofit their aircraft to meet the year 2020 requirement … yet the aircraft owners really got nothing in return. So to sweeten the bitter pill, it was decided the FAA would transmit weather radar (which until recently was a third party paid for service from companies such as XM satellite) and other useful pilot information. The new transmission is called FIS-B (flight information service broadcast) and is transmitted from ground stations to the aircraft and received using an ADS-B In receiver. The ADS-B In receiver also receives the ADS-B Out position transmissions from other aircraft in the vicinity which can subsequently be displayed on a screen in the aircraft.


The FIS-B signal transmitted from ground stations allows an ADS-B In equipped aircraft to receive NEXRAD (near real-time weather radar) information which can be overlaid onto a moving map. In addition, flight service information including METARs (aviation weather reports), TAF’s (terminal area forecasts), TFRs (temporary flight restrictions), PIREP (pilot in-flight reports), winds aloft and much more can be received. All great stuff to have available inside the cockpit … especially during cross country trips.


One nice thing about having a Dynon SkyView is if the aircraft is also equipped with Dynon’s ADS-B In receiver, the SkyView can not only display the FSI-B information mentioned above but it also displays information about other aircraft in the vicinity on the moving map without the need for additional displays in the cockpit. The displayed information can include the aircraft identification, position information, altitude above or below your aircraft (also shows if the target is ascending or descending) and a trend vector showing where the target aircraft will be in 60 seconds based on its current trajectory through the air. All very cool stuff!  The ADS-B In information can be received directly from other aircraft in the vicinity via transmissions between the aircraft or from ground stations. The FAA has adopted two frequency standards for ADS-B out transmissions …. 978 MHz UAT (Universal Access Transmitter) and 1090 MHz called 1090ES (Extended Squitter). The 978 MHz UAT is the FAA’s preferred ADS-B Out frequency for aircraft primarily flown below 18,000 feet and 1090ES is primarily for aircraft flown above 18,000 feet (primarily commercial aircraft).


The reason for removing the SV-ADSB-470 ADS-B In receiver initially installed in the DOG Aviation RV-12 is because it only receives one frequency (978 MHz) so aircraft broadcasting on the higher 1090 MHz frequency may not be displayed on the Dynon SkyView unless relayed by a ground station. Last year, Dynon announced the new SV-ADSB-742 ADS-B In receiver which receives both frequencies … now all aircraft equipped with ADS-B Out whether using 978 or 1090 MHz will be seen on the SkyView map screen.


To Dynon’s credit, Dynon offered SkyView owners who originally purchased the single frequency SV-ADSB-470 an opportunity to exchange their ADSB-470 box for the new SV-ADSB-472 dual frequency ADS-B In receiver at a fraction of the cost of the 472. To me that was a no brainer … so I signed up for the exchange program.


It amazes me how small the new dual band SV-ADSB-472 receiver is compared to the original SV-ADSB-470 box. The 470 spanned the entire area above the Garmin radio as can be seen in the photo below. (This confirms a long held belief of mine that one has to just accept the fact that when purchasing electronic items, they are pretty much obsolete the day you by them because technology is moving at such a rapid rate).

The Dynon SV-ADSB-470 single frequency (978 MHz) ADS-B In UAT receiver. Note how big this box is … it takes up the entire area above the Garmin GTR 200 radio rack.

Instillation of the new SV-ADSB-472 was quite easy … except for the time consuming task of removing all the screws necessary to gain access to the backside of the instrument panel. Fortunately, the new dual band SV-ADSB-472 receiver uses the same DB connector (which is almost half as big as the box) and antenna connection. However, because the 472 is SO MUCH SMALLER than the 470 box, it requires the addition of a mounting plate to span the top of the Garmin GTR 200 radio. The same mounting locations the 470 screwed into are used to mount the adapter plate. The new mounting plate can be ordered directly from Van’s. As one can see from the photos below, the connections to the SV-ADSB-472 are on the right and left ends ... whereas the connections to the original SV-ADSB-470 were along the front edge of the box. This almost created a problem with the antenna cable, but fortunately after rerouting the cable a little, there was just enough slack to attach the antenna cable to the 472 box.

Completed instillation of Dynon’s SV-ADSB-472 ADS-B In receiver. Note how much of the mounting plate is exposed … the old 470 box covered this entire area. By comparison, the new 472 box is really small. My finger is pointing to the DB connector which is almost half as big as the new 472 box.

Another view of the completed SV-ADSB-472 instillation showing how small this box is compared to the first photo posted above of the old 470 box which completely covers the top of the Garmin GTR 200 radio.


After installing the new SV-ADSB-472 receiver, a configuration change needs to be made to the SkyView’s serial port the 472 box is connected to. First verify the SkyView’s software version … the SV-ADSB-742 receiver REQUIRES the software to be Version 15.1 or newer to support the 472 box. If that is OK, the next step is to configure the serial port the 472 is wired to … this is done by entering the Setup Menu by pressing and holding down buttons 7&8 on the SkyView and then navigating to the serial port the 472 is wired to (it will be the same serial port the old 470 was wired to if upgrading as I was). SETUP MENU > SYSTEM SETUP > SERIAL PORT SETUP > SERIAL PORT x SETUP (the serial port the SV-ADSB-472 is wired to) > SERIAL IN DEVICE > SV-ADSB-472 > ACCEPT (button).


At this point the SV-ADSB-472 receiver should be configured properly and the serial port it is wired to should be showing transmit and receive packets incrementing as the SkyView and 472 box talk back and forth … if so, tap yourself on the back for a job well done.