Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes

The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD- 500-1A11 airplanes. This proposed AD was prompted by the discovery that titanium fasteners had been incorrectly installed in the butt strap at the outer wing box lower skin to center wing box interface in lieu of the correct nickel alloy fasteners. This proposed AD would require the identification of fasteners installed in the butt strap at the outer wing box lower skin to center wing box interface, and applicable on- condition actions. The FAA is proposing this AD to address the unsafe condition on these products.