2006-23-17: Centrifugal compressor intake wheel blades

2006-23-17 Turbomeca: Amendment 39-14829. Docket No. FAA-2006-25970; Directorate Identifier 99-NE-12-AD. Effective Date (a) This airworthiness directive (AD) becomes effective December 21, 2006. Affected ADs (b) This AD supersedes AD 2003-11-09, Amendment 39-13168. Applicability (c) This AD applies to Turbomeca Turmo IV A and IV C series turboshaft engines. These engines are installed on but not limited to Aerospatiale SA 330--PUMA helicopters. Unsafe Condition (d) This AD results from Turbomeca's review of the engines' service experience that determined more frequent borescope inspections are required on engines not modified to the TU 191, TU 197, or TU 224 standard. The actions specified in this AD are intended to prevent centrifugal compressor intake wheel blade cracks, which can result in engine in-flight power loss, engine shutdown, or forced landing. 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. Engine Modification Before Further Flight (f) For engines modified to the TU 197 standard, but not to the TU 191 or TU 224 standard, before further flight, remove the TU 197 standard and install the TU 224 standard. Initial Inspections (g) For all engines, borescope-inspect, and either eddy current- inspect (ECI) or ultrasonic-inspect (UI) the centrifugal compressor intake wheel blades using paragraphs 2.B.(1)(a) through 2.B.(1)(g) of Turbomeca Mandatory Service Bulletin A249 72 0100, Update No. 5, dated February 25, 2005, and the criteria in the following Table 1: Table 1.--Inspection Criteria If engine modification level is: Then borescope-inspect centrifugal compressor intake wheel blades: Were traces of corrosion found at borescope-inspection? Then confirm corrosion by performing ECI or UI within: (1) Pre TU 191 and Pre TU 224. Within 200 flight hours-since-last inspection. (i) Yes Six months-or 50 flight hours-since-borescope inspection, whichever occurs first. (ii) No Two hundred flight hours-since-borescope inspection. (2) Post TU 191 or Post TU 224. Within 1,000 flight hours-since-last inspection. (i) Yes Six months-or 50 flight hours-since-borescope inspection, whichever occurs first. (ii) No One thousand flight hours-since-borescope inspection. (h) Thereafter, perform repetitive inspections using the criteria in Table 1 of this AD. (i) Remove centrifugal compressor intake wheel blades confirmed cracked or pitted. Alternative Methods of Compliance (j) 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. Material Incorporated by Reference (k) You must use Turbomeca Mandatory Service Bulletin A249 72 0100, Update No. 5, dated February 25, 2005, to perform the actions 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) and 1 CFR part 51. You can get a copy of this service information from Turbomeca, 40220 Tarnos, France; telephone 33 05 59 74 40 00, fax 33 05 59 74 45 15. 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 . Related Information (l) Direction Generale de L'Aviation Civile airworthiness directive F-2005-037, dated March 2, 2005, also addresses the subject of this AD.