2006-21-10: Splines of high-pressure (HP) pump drive gear shaft

2006-21-10 Turbomeca: Amendment 39-14795. Docket No. FAA-2005-23809; Directorate Identifier 2005-NE-52-AD. Effective Date (a) This airworthiness directive (AD) becomes effective November 24, 2006. Affected ADs (b) None. Applicability (c) This AD applies to Turbomeca Arriel 2B, 2B1, and 2B1A turboshaft engines. These engines are installed on, but not limited to, Eurocopter AS350B3 and EC130B4 helicopters. Unsafe Condition (d) This AD results from reports of uncommanded in-flight shutdowns of engines. We are issuing this AD to detect wear on the splines of the high-pressure (HP) pump drive gear shaft and the coupling shaft assembly, which could interrupt the fuel flow and cause an uncommanded in-flight shutdown of the engine on a single- engine helicopter. The in-flight shutdown of the engine could result in a forced autorotation landing or accident. Compliance (e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. Initial Visual Inspection (f) Perform an initial visual inspection of the splines of the coupling assembly and the HP pump drive gear shaft for wear. Use 2.A. through 2.C.(2) of the Instructions to be Incorporated of Turbomeca Mandatory Service Bulletin (MSB) No. 292 73 2812, Update No. 2, dated June 28, 2005, as follows: (1) For hydraulic mechanical units (HMUs) that have accumulated 450 or more hours time-since-new (TSN) or time-since-overhaul (TSO) on the effective date of this AD, inspect within 50 hours after the effective date of this AD. Replace the HMU if worn beyond limits. (2) For HMUs that have fewer than 450 hours TSN or TSO on the effective date of this AD, inspect after accumulating 450 hours TSN or TSO, but before accumulating 500 hours TSN or TSO. Replace the HMU if worn beyond limits. Repetitive Visual Inspections (g) Thereafter, perform a visual inspection of the splines of the coupling shaft assembly and the HP pump drive gear shaft for wear every time you remove or install the HMU. Use 2.A. through 2.C.(2) of the Instructions to be Incorporated of Turbomeca MSB No. 292 73 2812, Update No. 2, dated June 28, 2005. Replace the HMU and coupling shaft assembly if worn beyond limits. Alternative Methods of Compliance (h) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19. Related Information (i) DGAC airworthiness directive F-2005-188, dated November 23, 2005, also addresses the subject of this AD. Material Incorporated by Reference (j) You must use Turbomeca Mandatory Service Bulletin No. 292 73 2812, Update No. 2, dated June 28, 2005, to perform the visual inspections required by this AD. The Director of the Federal Register approved the incorporation by reference of this service bulletin in accordance with 5 U.S.C. 552(a) and1 CFR part 51. Contact Turbomeca, 40220 Tarnos--France; Tel (33) 05 59 74 40 00; Telex 570 042; Fax (33) 05 59 74 45 15, for a copy of this service information. You may review copies at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html .