Originally Posted by lr172
This is a pretty critical joint that can get a fair amount of stress from forces on the elevator and opposed by the control system. I wouldn't too quickly write off their concerns about pull rivets working loose. In most applications I wouldn't think twice about it. However, I see this a pretty critical connection, as it directly ties the elevator to the control system.
I think you may have misunderstood which connection we're talking about. The WD-1222's hold the counter balance tube, not the stabilator.
Also, the WD-1222 is getting riveted to the .040 aluminum of the HS-01203 spar, which is probably why there are 12 rivets each on the front and rear WD-1222's. How strong does a rivet need to be that is connecting something to an .040 piece of aluminum?
There is something that is a bit confusing to me though... The WD-1207-1 and the WD-1208-1 (the stabilator control horns) do carry the stress of the control cables moving the stabilator and those two brackets get riveted to the same spar as the WD-1222 but with BSPQ-5-2 blind rivets. The difference being that the WD-1222's get riveted before the spar tube is closed and therefore you have access to both ends of the rivet which means you can use an AN470. However, the WD-1207-1 and the WD-1208-1 don't get riveted until after the spar is formed into a box and there is no access to the shop head side of the rivet for squeezing, so a blind rivet or bolt into a nut plate would be your only options. The plans call for BSPQ-5-2 blind rivets for the stabilator horns. Curious.