Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2020-25-05, which applies to all Hoffmann GmbH & Co. KG (Hoffmann) model HO-V 72 propellers. AD 2020-25-05 requires amending the existing aircraft flight manual (AFM) with abnormal propeller vibration instructions. AD 2020-25-05 also requires visual inspection and non- destructive test (NDT) inspection of the propeller hub and, depending on the results of the inspections, replacement of the propeller hub with a part eligible for installation. AD 2020-25-05 also requires replacement of the propeller hub before exceeding 30 years since the date of manufacture. Since the FAA issued AD 2020-25-05, analyses of the inspection results showed that the 30-year life limit of the propeller hub is no longer needed. This proposed AD would retain certain requirements of AD 2020-25-05 and remove the 30-year life limit of the propeller hub. The FAA is proposing this AD to address the unsafe condition on these products.