Airworthiness Directives; Bell Helicopter Textron Canada Model 206L, L-1, L-3, L-4, and 407 Helicopters

We are adopting a new airworthiness directive (AD) for the specified Bell Helicopter Textron Canada (BHTC) helicopters. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority to identify and correct an unsafe condition on an aviation product. The Aviation Authority of Canada with whom we have a bilateral agreement states in the MCAI: "Horizontal stabilizers part numbers 206-023-119-167 and 407-023-801-109 may have manufacturing flaws on the inside surface of the upper and/or lower skin at the tailboom attachment inserts. These flaws may result in cracking of the skin and failure of the horizontal stabilizer." The manufacturer's service information states that in addition to cracks, the horizontal stabilizer may have deformation or debonding around and between the inserts. We are issuing this AD to require actions to correct the unsafe condition on these products.