AD 2005-17-01 Airworthiness Directives; Pilatus Aircraft Ltd. Models PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 Airplanes

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

(c) This AD affects the following airplanes, all manufacturer serial numbers (MSN), that are certificated in any category. Note 1: These airplanes are also identified as Fairchild Republic Company PC-6 series airplanes and Fairchild Heli Porter PC-6 series airplanes.   Models (1) PC-6 (2) PC-6-H1 (3) PC-6-H2 (4) PC-6/350 (5) PC-6/350-H1 (6) PC-6/350-H2 (7) PC-6/A (8) PC-6/A-H1 (9) PC-6/A-H2 (10) PC-6/B-H2 (11) PC-6/B1-H2 (12) PC-6/B2-H2 (13) PC-6/B2-H4 (14) PC-6/C-H2 (15) PC-6/C1-H2

(e) To address this problem, you must do the following:   Actions Compliance Procedures (1) Inspect the following: (i) the stabilizer-trim attachment and structural components (fitting, connecting piece, bearing fork, bearing support assembly, and auxiliary frame, as applicable) for cracks and corrosion; and (ii) the diameters of the actuator attachment bolt holes on the fittings, auxiliary frame, and connecting piece (as applicable) for discrepancies. Within the next 100 hours time-in-service (TIS) after September 29, 2005 (the effective date of this AD). Repetitively inspect thereafter at intervals not-to-exceed 3,500 hours TIS or 7 years, whichever occurs first. Follow Pilatus PC-6 Service Bulletin No. 53-001, Rev. No. 1, dated June 1, 2005. (2) If cracks are found during any inspection required in paragraph (e)(1)(i) of this AD, replace the defective part with a new part. Replace the defective part before further flight after the inspection in which cracks are found. After each replacement, continue with the repetitive inspection requirement in paragraph (e)(1) of this AD. Follow Pilatus PC-6 Service Bulletin No. 53-001, Rev. No. 1, dated June 1, 2005. (3) If corrosion or discrepancies are found during any inspection required in paragraphs (e)(1)(i) and (e)(1)(ii) of this AD, do the following: (i) replace the defective part with a new part if the corrosion or discrepancy is beyond the repairable limits stated in the service information; or (ii) repair the defective part if the corrosion or discrepancy is within the repairable limits stated in the service information. Replace or repair the defective part before further flight after the inspection in which corrosion or discrepancies are found. After each replacement or repair, continue with the repetitive inspection requirement in paragraph (e)(1) of this AD. Follow Pilatus PC-6 Service Bulletin No. 53-001, Rev. No. 1, dated June 1, 2005. (4) Replace the following: (i) all Fairchild connecting pieces, part number (P/N) 6232.0026.XX, with a Pilatus connecting piece, P/N 6232.0026.XX. The Fairchild part has a rivet in the middle that is not on the Pilatus part; and (ii) all fittings, P/N 116.40.06.033 without an index after the P/N, with an improved part, P/N 116.40.06.033 with an index of “A” or “B” after the P/N or with P/N 116.40.06.112. Within the next 100 hours TIS after September 29, 2005 (the effective date of this AD). After replacement, repetitively inspect thereafter at intervals not-to-exceed 3,500 hours TIS or 7 years, whichever occurs first. If after the inspection required in paragraph (e)(1) of this AD, you determine that you already have a P/N 116.40.06.033 with an index of “A” or “B” or a P/N 116.40.06.112 installed, repetitively inspect thereafter at intervals not-to-exceed 3,500 hours TIS or 7 years, whichever occurs first after the part was installed. Follow Pilatus PC-6 Service Bulletin No. 53-001, Rev. No. 1, dated June 1, 2005. (5) Do not install any of the following: (i) Fairchild connecting piece, P/N 6232.0026.XX (it has a rivet in the middle that is not on the Pilatus part); and (ii) fitting, P/N 116.40.06.033, without an index after the part number. As of September 29, 2005 (the effective date of this AD). Follow Pilatus PC-6 Service Bulletin No. 53-001, Rev. No. 1, dated June 1, 2005. Note 2: Even though not required in this AD, the FAA recommends that you send all defective parts to Pilatus at the address specified in paragraph (h) of this AD. With the part, include the aircraft serial number, flying hours, and cycles.

(d) This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. We are issuing this AD to detect and correct cracks in the stabilizer-trim attachment and surrounding structural components, which could result in failure of the stabilizer-trim attachment. This failure could lead to loss of control of the airplane.

(b) None.