Emergency Airworthiness Directive Issued for Select Bell 505 Helicopters
The Federal Aviation Administration (FAA) has issued an Emergency Airworthiness Directive (AD) 2026-05-51 for specific Bell 505 helicopters. This directive comes in the wake of a critical safety defect discovery that could potentially lead to a total loss of control.
This emergency AD was instigated by the Transport Canada Emergency AD CF-2026-12 issued on March 3, 2026. The directive addresses a malfunction of the hinge assembly on the aft movable ballast box assembly. This defect could potentially allow ballast weights to break free and strike the tail rotor assembly, causing catastrophic damage and severe vibrations, ultimately leading to the loss of helicopter control.
The directive is applicable to Bell Model 505 helicopters, serial numbers 65011 and subsequent, with specific ballast box assembly part numbers installed. The AD mandates an immediate revision of 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. Bell has identified possible plastic deformation and improper pin engagement in the door hinge knuckles of the affected assemblies.
Source: Federal Register