2003-12-14: Axial Compressor

2003-12-14 Turbomeca S.A.: Amendment 39-13199. Docket No. 2002-NE-43-AD. Applicability: This airworthiness directive (AD) is applicable to Turbomeca S.A. Arriel 1 A, 1 A1, 1 A2, 1 B, 1 C, 1 C1, 1 C2, 1 D, 1 D1, 1 E, 1 E2, 1 K, 1 K1, 1 S, and 1 S1 turboshaft engines. These engines are installed on, but not limited to, Eurocopter AS 350, AS 350B1, AS 350B2, AS 365C, AS 365C2, AS 365N, AS 365N1, AS 365N2, BK 117C1, BK 117C2, Augusta A109 K2, and Sikorsky S76 C helicopters. Note 1: This AD applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. Compliance: Compliance with this AD is required as indicated, unless already done. To prevent an unbalance of the gas generator rotating assembly which may lead to deterioration of the gas generator rear bearing and also to uncommanded engine shutdown, do the following: Initial Inspections and Cleaning (a) For engines that have been operated in a dusty or erosive atmospheric environment containing substances such as laterite, sand, volcanic ash, and chemical particles, and engines for which the operating environment cannot be determined, do the following: (1) Perform an initial visual inspection for erosion of the axial compressor, within 50 operating hours after the effective date of this AD. Information on inspecting can be found in Turbomeca S.A. Mandatory Service Bulletin (MSB) No. 292 72 0230, dated October 16, 1998. Modification TU 175 Not Incorporated (2) For engines that do not have Modification TU 175 incorporated, if axial compressor erosion is above 1.5 millimeters in area III as defined in the engine maintenance manual, even if it has not reached 1,000 operating hours, and if the module M03 has operated more than 200 hours with this M02 module, clean the M03 module within the next 50 operating hours. Information on cleaning can be found in Turbomeca S.A. MSB No. 292 72 0230, dated October 16, 1998. Modification TU 175 Incorporated (3) For engines that have Modification TU 175 incorporated, if axial compressor erosion inspection requires the M02 module to be removed, and if the M03 module has operated more than 400 hours with this M02 module, clean the M03 module within the next 50 operating hours. Information on cleaning can be found in Turbomeca S.A. MSB No. 292 72 0230, dated October 16, 1998. Reconditioning and Checks (b) Perform reconditioning and checks of the engines. Information on reconditioning and checks can be found in Turbomeca S.A. MSB No. 292 72 0230, dated October 16, 1998. Repetitive Inspections (c) Repeat axial compressor erosion inspections within every 200 operating hours-since-last-inspection (HSLI) for engines that do not have Modification TU 175 incorporated, and within every 400 operating HSLI, for engines that have Modification TU 175 incorporated, as specified in paragraph (a) of this AD. Alternative Methods of Compliance (d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office (ECO). Operators must submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO. Note 3: A list of authorized repair centers qualified to carry out gas generator rotating assembly maintenance and cleaning may be obtained from Turbomeca S.A. or the ECO. Special Flight Permits (e) Special flight permits may be issued in accordance with 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be done. Note 4: The subject of this AD is addressed in Direction Generale de L'Aviation Civile airworthiness directive 1990-064(A), Revision 1, dated March 21, 2000. Effective Date (f) This amendment becomes effective on July 25, 2003.