The flap had a few cracks that we had known about. One of the most obvious was across one of the stiffening ribs in the top skin. Turns out it is illegal to stop-drill that so the only solution was to reskin it. It shipped out with the stabilizer.
In order to remove the horizontal stabilizer the vertical stabilizer needs to be removed as well. This is the first time I've seen the tail removed from this airplane (or any other) and I hope it's my last.
A closeup of the right side of the tail with the stabilizers removed. The holes on the forward bulkhead where the control cables come through in the center accept the bolts that fasten the horizontal tail section to the empennage.
Another perspective on the tail. The rear bulkhead that forms the rear of the tail is a very substantial solid aluminum casting. I'm sure it was designed to take abuse.
This picture is of the horizontal stabilizer, still attached to the airplane, looking toward the nose. The crack is circled with a marker. If you look closely, you can tell that the lightening hole is already doubled and it STILL cracked. Obviously this is a high stress point in the design.
Surprise, surprise. The spar has buckled under the load in the vicinity of the cracks. We're not sure which came first, but even though the service bulletin covering the repair allows stop-drilling of the cracks, the buckling is a clear sign that the thing needs to be repaired.
Another picture of the crack on the right side of the spar as viewed from the rear.
The new hub installed. The obvious enhancements to the design include grease fittings relocated to a low-stress area and fillets added to the area that wrap the blade shanks. If looks count for anything, this is indeed a stronger design.
Another perspective on the new hub. There has been one reported failure of the hub (the one that influenced the creation of the AD, and cracks in 6 others. Probably a good idea to replace the hub sooner rather than later if you are affected by this.