AD 2006-05-05 Airworthiness Directives; MT-Propeller Entwicklung GmbH Propellers

Makes named: mt-propeller. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to MT-Propeller Entwicklung GmbH, models MT, MTV-1, MTV-2, MTV-3, MTV-5, MTV-6, MTV-7, MTV-9, MTV-10, MTV-11, MTV-12, MTV-14, MTV-15, MTV-17, MTV-18, MTV-20, MTV-21, MTV-22, MTV-24, and MTV-25 propellers with serial numbers (SNs) below 95000, which have not been overhauled since April 1994. These propellers may be installed on but not limited to, Sukhoi SU-26, SU-29, SU-31; Yakovlev YAK-52, YAK-54, YAK-55; and Technoavia SM-92 airplanes.

You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. Note 1: Information about inspection procedures and acceptable limits can be found in Table 1 of this AD. Overhaul of Propeller Blades (f) Overhaul all propeller blades of propellers listed in the applicability, within 30 days after the effective date of this AD. Initial Visual Inspection of the Propeller Blade (g) During the next preflight inspection or 100-hour inspection, whichever occurs first, after the effective date of this AD, inspect all MT and MTV propellers by doing the following: (1) Determine if the erosion sheath of any propeller blade is cracked or loose; and (2) Determine if any propeller blade has other damage out of acceptable limits. (3) Before the next flight, remove from service those propeller blades with a cracked or loose erosion sheath, or other damage affecting airworthiness. Table 1.—Service Information For propeller model . . . See operation and installation manual . . . MT No. E-112, issued Nov. 1993 or later. MTV-1, MTV-7, MTV-10, MTV-17, MTV-18, MTV-20 No. E-118, issued March 1994 or later. MTV-5, MTV-6, MTV-9, MTV-11, MTV-12, MTV-14, MTV-15, MTV-21, MTV-22, MTV-25 No. E-124, issued March 1994 or later. MTV-2, MTV-3 No. E-148, issued March 1994 or later. MTV-24 No. E-309, issued March 1994 or later. Initial Visual Inspection of the Propeller Blade Polyurethane Strip (h) During the next pilot's preflight inspection after the effective date of this AD, if the polyurethane protective strip on the leading edge of the inner portion of the blade is found to be damaged or missing, the polyurethane protective strip must be replaced or installed within 10-flight hours. If electrical de-icing boots are installed, no polyurethane protective strips are required. Repetitive Visual Inspection of the Propeller Blade (i) If after the effective date of this AD, any propeller blade erosion sheath found to be cracked or loose during the pilot's preflight inspection, or 100-hour inspection, or annual inspection, must be repaired, replaced, or overhauled before the next flight. Repetitive Visual Inspection of the Propeller Blade Polyurethane Strip (j) If after the effective date of this AD, any propeller blade polyurethane protective strip found to be damaged or missing during the pilot's preflight inspection, or 100-hour inspection, or annual inspection, must be replaced or installed within 10-flight hours. If electrical de-icing boots are installed, polyurethane protective strips are not required. Alternative Methods of

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.