Regulacje i polityka gospodarcza · 1.11.2022

Airworthiness Directives; Hoffmann GmbH & Co. KG Propellers

The FAA is superseding Airworthiness Directive (AD) 2021-23-17 for all Hoffmann GmbH & Co. KG (Hoffmann) model HO-V 72 propellers. AD 2021-23-17 required amending the existing aircraft flight manual (AFM) by inserting abnormal propeller vibration instructions, 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. Since the FAA issued AD 2021-23-17, further investigation by the manufacturer revealed that cracks found on propeller hubs likely resulted from propeller blade retention nuts that were not tightened using published service information during blade installation. This AD is prompted by reports of cracks at different positions on two affected propeller hubs. This AD retains the required actions of AD 2021-23-17. This AD also requires a maintenance records review and, depending on the results of the maintenance records review, tightening of each propeller blade retention nut to specific torque values. Depending on the results of the maintenance records review, this AD requires physically inspecting the propeller blade for shake. I