Airworthiness Directives; Bell Textron Canada Limited Helicopters

The FAA proposes to supersede Airworthiness Directive (AD) AD 2024-02-55, which applies to certain Bell Textron Canada Limited (BTCL) Model 505 helicopters. AD 2024-02-55 requires initial and recurring inspections of the vertical stabilizer top end cap assembly and corrective action if a crack is found. Since the FAA issued AD 2024-02- 55, the manufacturer introduced a new one-piece vertical stabilizer machined top end cap assembly, which is implemented during production, and designed a new replacement for the vertical stabilizer machined top end cap assembly currently in service. This proposed AD would continue to require the inspection requirements of AD 2024-02-55 and would limit the applicability to exclude certain serial numbered BTCL Model 505 helicopters with an improved design vertical stabilizer top end cap installed at production. This proposed AD would also require replacing the vertical stabilizer top end cap assembly with an improved design top end cap assembly, which would constitute terminating action for the recurring detailed visual inspections. The FAA is proposing this AD to address the unsafe condition on these products.