99-04-09: High Pressure Turbine Disk

99-04-09 Rolls-Royce Limited: Amendment 39-11033. Docket 98-ANE-46-AD. Applicability: Rolls-Royce Limited (R-R) Dart 525 series, 526, 527, 528 series, 529 series, 530, 531, 532 series, 535 series, 542 series, and 552 series turboprop engines, installed on but not limited to Gulfstream Aerospace Corp. G-159, British Aerospace HS 748, Fokker Aircraft F27, Fairchild Hiller FH227, Mitsubishi Heavy Industries YS-11, General Dynamics (Convair) 640 and 600 series, and Vickers Armstrong (Aircraft Limited) Viscount aircraft. Note 1: This airworthiness directive (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 (e) 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: Required as indicated, unless accomplished previously. To prevent high pressure turbine (HPT) disk rupture, which can result in an uncontained engine failure, engine fire, and damage to the aircraft, accomplish the following: (a) For engines with a complete set of HPT blades that were either inspected and reworked to D.R.S. 611 standard or were installed new at last HPT rework or engine overhaul, perform fuel burner fuel flow calibration checks and overhaul or replacement of fuel burners in accordance with R-R Alert Service Bulletin (ASB) No. Da73-A87, dated May 1998, at each engine overhaul, or prior to exceeding 3,000 hours time in service (TIS) since last fuel burner calibration, whichever occurs first. (b) Inspection to the D.R.S. 611 standard requires the HPT blades to have both the inner platform and shroud inspected to this standard. This inspection requirement was added to the Engine Overhaul Manual in 1992. Inspection to the D.R.S. 611 standard prior to this date must be considered to be pre-D.R.S. 611 standard. (c) For engines with HPT blades that have not been inspected and modified during the last engine or HPT overhaul using the D.R.S. 611 build standard, perform initial and repetitive fuel burner fuel flow calibration checks and overhaul or replacement of fuel burners in accordance with R-R ASB No. Da73-A87, dated May 1998, as follows: (1) For engines with 6,000 or more hours time in service (TIS) since last HPT overhaul and rework, perform the initial check and overhaul as follows: (i) For fuel burners with more than 850 hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding an additional 150 hours TIS after the effective date of this AD, but not to exceed 1,000 hours TIS since last fuel burner calibration after June 30, 1999. (ii) For fuel burners with 850 or less hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding 1,000 hours TIS since last fuel burner calibration. (2) For engines with 5,000 or more hours but less than 6,000 hours TIS since last HPT overhaul and rework, perform the initial check and overhaul as follows: (i) For fuel burners with more than 700 hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding an additional 300 hours TIS after the effective date of this AD, but not to exceed 1,000 hours TIS since last fuel burner calibration after June 30, 1999. (ii) For fuel burners with 700 or less hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding 1,000 hours TIS since last fuel burner calibration. (3) For engines with 4,000 or more hours but less than 5,000 hours TIS since last HPT overhaul and rework, perform the initial check and overhaul as follows: (i) For fuel burners with more than 550 hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding an additional 450 hours TIS after the effective date of this AD, but not to exceed 1,000 hours TIS since last fuel burner calibration after June 30, 1999. (ii) For fuel burners with 550 or less hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding 1,000 hours TIS since last fuel burner calibration. (4) For engines with less than 4,000 hours TIS since last HPT overhaul and rework, perform the initial check and overhaul as follows: (i) For fuel burners with more than 100 hours TIS since last fuel burner calibration, performthe fuel flow check and calibration prior to exceeding an additional 900 hours TIS after the effective date of this AD, but not to exceed 1,000 hours TIS since last fuel burner calibration after June 30, 1999. (ii) For fuel burners with 100 or less hours TIS since last fuel burner calibration, perform the fuel flow calibration check and overhaul prior to exceeding 1,000 hours TIS since last fuel burner calibration. (5) Thereafter, perform repetitive fuel burner fuel flow calibration checks and overhauls at intervals not to exceed 1,000 hours TIS since last fuel burner fuel flow calibration check. (d) After the effective date of this AD, no new fuel burner may be installed unless it has been subject to a satisfactory fuel flow calibration check within 3 years prior to installation, and no fuel burner run since last overhaul, including those fitted to a combustion chamber, may be installed unless it has been subject to a satisfactory fuel flow calibration check in accordanceto R-R ASB Da 73-A87, dated May 1998, prior to installation. (e) 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. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office. (f) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be accomplished. (g) The actions required by this AD shall be performed in accordance with the following R-R ASB: Document No. Pages Date Da73-A87 1-8 May 1998 Total pages: 8. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Rolls-Royce Limited, Attn.: Dart Engine Service Manager, East Kilbride, Glasgow G74 4PY, Scotland. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (h) This amendment becomes effective on February 25, 1999.