2004-26-09: Compressor Adaptor Couplings

2004-26-09 Rolls-Royce Corporation (formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison): Amendment 39-13921. Docket No. FAA-2004-18515; Directorate Identifier 2004-NE-12-AD. Effective Date (a) This airworthiness directive (AD) becomes effective February 8, 2005. Affected ADs (b) None. Applicability (c) This AD applies to Rolls-Royce Corporation (formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison) 250-B17, -B17B, -B17C, -B17D, -B17E, 250-C20, -C20B, -C20F, -C20J, -C20S, and -C20W series turboprop and turboshaft engines with the compressor adaptor couplings installed listed in the following Table 1: Table 1.-Affected Compressor Adaptor Couplings Manufacturer Affected part numbers Alcor Engine Company (Alcor) P/Ns 23039791AL. 23039791AL-1/-2/-3. EXTEX Ltd. (EXTEX) A23039791. E23039791. E23039791-1/-2/-3. EH23039791. EH23039791-1/-2/-3. Rolls-Royce Corporation (RRC) 23039791-1/-2/-3. Superior Air Parts (SAP) A23039791. These engines are installed on, but not limited to, the aircraft in the following Table 2: Table 2.-Applicable Aircraft Helicopters Agusta Models. A109, A109A, A109A II. Bell Models. 206A, 207B, 206L. Enstrom Models. TH-28, 480, 480B. Eurocopter France Models. AS355E, AS355F, AS355F1, AS355F2. Eurocopter Deutschland Models. BO-105C, BO-105S. MDHI Models. 369D, 369E, 369H, 369HM, 369HS, 369HE. Schweizer Model 269D. Airplanes B-N Group Ltd. Model. BN-2T. Unsafe Condition (d) This AD results from nine reports of engine shutdown caused by compressor adaptor coupling failure. 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. Alcor Compressor Adaptor Couplings (f) Remove Alcor compressor adaptor couplings, P/Ns 23039791AL, 23039791AL-1, -2, and -3from service as follows: (1) For couplings with 600 or more operating hours-since-new as of the effective date of this AD, or the operating hours are unknown and cannot be determined, remove couplings from service at next access but not to exceed 50 additional operating hours. (2) For couplings with fewer than 600 operating hours-since-new on the effective date of this AD, remove couplings from service at next access but not to exceed 649 operating hours-since-new. EXTEX and SAP Compressor Adaptor Couplings (g) Remove EXTEX and SAP compressor adaptor couplings, P/Ns A23039791, E23039791, E23039791-1, -2, and -3, EH23039791, and EH23039791-1, -2, and -3, from service as follows: (1) For couplings with operating hours that are unknown and cannot be determined, remove couplings from service at next access but not to exceed 50 additional operating hours. (2) For couplings with 600 or more operating hours-since-new as of the effective date of this AD, remove couplings from service at next access but not to exceed 100 additional operating hours. (3) For couplings with fewer than 600 operating hours-since-new on the effective date of this AD, remove couplings from service at next access but not to exceed 150 additional operating hours. RRC Compressor Adaptor Couplings (h) Remove RRC compressor adaptor couplings, P/Ns 23039791-1, -2, and -3 from service next time the compressor rotor is disassembled for any reason, but not later than March 1, 2012. Installation Requirements for Compressor Adaptor Couplings (i) Machine the compressor impeller as follows: (1) Select and measure the pilot outside diameter (OD) of a new larger dash size coupling. (2) For example, if a -1 coupling was removed, a -2 coupling must be installed. (3) If a -3 coupling is removed, a new impeller is required. (4) Machine the inside diameter (ID) of the compressor impeller to achieve a fit of 0.0000 to -0.0013 inch. No fretting isallowed on the impeller after machining. (5) Due to previous fretting, an impeller with a -1 coupling removed might have to be machined for a -3 coupling. Plating of the impeller ID is not allowed. (6) Fluorescent penetrant inspect the impeller. (7) Install a new compressor adaptor coupling, P/N 23076559-2 or -3; or (8) If a new impeller is installed, then install compressor adaptor coupling, P/N 23076559-1. (9) Heating of the impeller per the engine overhaul manual is required to install the coupling to achieve the target fit specified in the following Table 3: Table 3.-Impeller-to-Coupling Target Fit New adaptor Adaptor OD Fit (interference) (i) 23076559-1 0.9000 to 0.9008 inch 0.0000 to -0.0013 inch. (ii) 23076559-2 0.9020 to 0.9028 inch 0.0000 to -0.0013 inch. (iii) 23076559-3 0.9040 to 0.9048 inch 0.0000 to -0.0013 inch. (10) The mating surfaces of the impeller and coupling must not have any fretting. Do not install a -1 coupling into a used impeller. Definition (j) For the purposes of this AD, next access is defined as when the compressor module is separated from the engine and disassembled for any reason. Alternative Methods of Compliance (k) The Manager, Los Angeles Aircraft Certification Office, has the authority to approve alternative methods of compliance for Alcor, EXTEX, and SAP adaptor couplings addressed in this AD if requested using the procedures found in 14 CFR 39.19. The Manager, Chicago Aircraft Certification Office, has the authority to approve alternative methods of compliance for RRC adaptor couplings addressed in this AD if requested using the procedures found in 14 CFR 39.19. Related Information (l) Alcor SLB No. 814-3-1, Revision C, dated April 28, 2004, EXTEX Alert Service Bulletin T-081, Revision B, dated May 4, 2004, and RRC CEB-A-1392 and CEB-A-1334, dated September 9, 2003, pertain to the subject of this AD.