AD 2021-19-08 Prompted By Reports Of Cracked Tail Rotor Blades

The FAA is adopting a new airworthiness directive (AD) for certain Robinson Helicopter Company Model R44 and R44 II helicopters.

This AD was prompted by reports of cracked tail rotor blades (blades). This AD requires checking each blade for any crack and removing any cracked blade from service. This AD also requires removing all affected blades from service and prohibits installing any affected blade on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective September 22, 2021.

Supplementary Information: The FAA received reports of spanwise cracks found along the leading edge of part number (P/N) C029-3 blades, serial numbers (S/N) 9410 through 9909. These affected blades were factory-installed or shipped as spares between March and December 2019. The cracks were found at different inspection intervals ranging from preflight inspections to 100-hour inspections. In one instance, a cracked blade was suspected when the pilot felt abnormal vibrations during flight; subsequent investigation determined that the blade was cracked. The cause of the cracks is a manufacturing defect in the properties of the blade skin that makes the blades prone to stress corrosion cracking.

This condition, if not addressed, could result in reduced controllability and subsequent loss of control of the helicopter. The FAA is issuing this AD to address the unsafe condition on these products.

FMI: www.regulations.gov