Emergency Airworthiness Directive for Bell 505 Helicopters Issued by FAA
The Federal Aviation Administration (FAA) has issued an emergency airworthiness directive (AD 2026-05-51) for certain Bell 505 helicopters. This directive follows the discovery of a critical safety issue that could lead to a total loss of control.
The emergency order was issued in March 2026 and formalized in April. It addresses a potential failure of the hinge assembly on the aft movable ballast box assembly. This failure could allow ballast weights to escape and strike the tail rotor assembly during flight. Notably, this directive was issued just days after Transport Canada issued its own emergency order regarding the same issue.
The AD applies to Bell Textron Canada Limited Model 505 helicopters with serial numbers 65011 and subsequent. These helicopters are equipped with ballast box assembly part numbers SLS-706-201-207 or SLS-706-201-207FM. The FAA now requires operators to revise the Limitations section of the rotorcraft flight manual. This revision is to prohibit the use of ballast weights within the affected aft movable ballast box assembly.
According to the MCAI from Transport Canada, Bell discovered “possible plastic deformation and improper pin engagement in the knuckles of the door hinge” on the aft movable ballast box assembly. If left uncorrected, this condition could lead to catastrophic consequences.
The emergency AD became effective on April 16, 2026, for operators who did not receive direct notice. Since then, Bell has developed a modification involving a longer two-inch hinge assembly and adjusted rubber pad thickness on the door.
Source: Federal Register