Airworthiness Directives; MT-Propeller Entwicklung GmbH Propellers

The FAA is adopting a new airworthiness directive (AD) for certain MT-Propeller Entwicklung GmbH variable pitch and fixed pitch propellers with serial numbers (SNs) below 95000, which have not been overhauled since April 1994. This AD requires overhauling the propeller blades of these propellers within 30 days after the effective date of the AD. This AD also requires performing initial and repetitive visual inspections of affected propeller blades. This AD also requires removing all propeller blades from service with damaged erosion sheath bonding or loose erosion sheaths and installing any missing or damaged polyurethane protective strips. This AD results from reports of stainless steel leading edge erosion sheaths separating from propeller blades and reports of propeller blades with damaged or missing polyurethane protective strips (PU-protection tape) due to insufficient inspection procedures in older MT-Propeller Entwicklung GmbH Operation & Installation Manuals. We are issuing this AD to prevent erosion sheath separation leading to damage of the airplane.