Service Bulletin SB 18-03-06: Cracks in the anti-servo tab skin.

On three high-time RV-12s (hours > 900) cracks were discovered in the skin of the anti-servo tab where the control horn attaches to the inboard-most rib.  All of the internal ribs in the AST have angled tabs at their leading edges which attach the rib to the spar and the skin.  The inboard end ribs,

to which the control horn attaches, did not have these tabs.  Makes sense, right?  The one rib which transmits all the load from the pitch input from the stick didn't, in the original design, connect to the spar in the leading edge of the anti-servo tab.  This original is shown in the picture.






The fix for the poor blokes with already-flying airplanes involved stop drilling any cracks, adding various doublers and replacing the end ribs.  For those of us with airplanes still under construction, all that was required was end-rib replacement.

One of the few benefits to working as slowly as I have is having an easier time with service bulletins.  The fix involved drilling out a total (both ASTs) of 10 solid rivets and 16 pulled rivets, match drilling some holes (my 273rd favorite thing), countersinking holes for the solid rivets, and re-installing everything.  I have become an absolute expert at drilling out rivets.

I appreciate the concept of service bulletins.  As the fleet ages, problem areas appear and a re-design of various parts ensures safety.  As I implement the changes, however, I feel that I'm simply treading water, re-doing something I've already done and making no progress toward that first flight.  The worst of these was the landing gear beef-up, but it's clearly a more solid airplane now.  I guess I'm just tired of building and ready to fly.  Building this airplane has been one of the most interesting things I've ever done, but I'm really ready to "slip the surly bonds of earth" (thanks again, John Magee, for the poem that has inspired me for most of life).  My new goal is to fly the airplane to my home in Colorado next summer.  I'm still on the waiting list for a hangar at KLMO, and have been called several times as one became available there, only to turn it down.  My big fear is that nothing will be available there when I'm ready to go.  That airport is 1.5 miles from my home, so no other airport makes sense.  I will, of course, have to have a hangar here in NC at KVUJ (three miles from my NC home) for the flight test period.  I think it's a fundamental law of nature that RVs can't live outside in the elements as so many store-bought airplanes do.