Horizontal Braces: i.e., CE-04-34

If a job is worth doing, it's worth over-doing.

I see a lot of horizontal braces. I mean, I maintain about 35 planes a year.  Add to that the Pre-Purchase inspections and other planes that I inspect and you get a general idea how many I see each year.  I would venture to guess that 20% of the planes I see have wrinkles in the lower cross brace. 

The question has always been, "Why do they crack?" I asked a DER many in 2004 to do a finite element analysis of the aft end of the plane. His conclusion was racking of the area due to 1) rudder deflection, followed by 2) the 12 foot horizontal following, then 3) twisting (racking) of the fuselage between the aft bulkhead and the bulkhead just forward of the ELT tray.