AD 2005-25-11

The FAA is superseding an existing airworthiness directive (AD) for Rolls-Royce plc (RR) models RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 884B-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines with low pressure (LP) compressor fan blades, part number (P/N) FW18548 installed. That AD currently requires LP compressor fan blade replacement with new or previously reworked blades, or rework of the existing LP compressor fan blades. This ad requires the same actions but at reduced compliance times for certain airplane and engine rating combinations and certain maximum gross weight limits. This AD results from a number of new production LP compressor fan blades found with surfaces formed outside of design intent. We are issuing this AD to prevent possible multiple uncontained LP compressor fan blade failure, due to cracking in the blade root caused by increased stresses in the shear key slots.

Final rule.

2005-25-11 Rolls-Royce plc: Amendment 39-14404. Docket No. 2003-NE- 38-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective January 17, 2006. \n\nAffected ADs \n\n\t(b) This AD supersedes AD 2004-15-02, Amendment 39-13736. \n\nApplicability \n\n\t(c) This AD applies to Rolls-Royce plc (RR) models RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 884B-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines, with low pressure (LP) compressor fan blades, part number FW18548 installed. These engines are installed on, but not limited to, Boeing 777 series airplanes. \n\nUnsafe Condition \n\n\t(d) This AD results from a number of new production LP compressor blades found with surfaces formed outside of design intent. We are issuing this AD to prevent possible multiple uncontained LP compressor fan blade failure, due to cracking in the blade root caused by increased stresses in the shear key slots. \n\nCompliance \n\n\t(e) You are responsible for having the actions requiredby this AD performed within the compliance times specified unless the actions have already been done. \n\nActions Required for LP Compressor Fan Blades \n\n\t(f) Replace LP compressor fan blades with new or previously reworked LP compressor blades before accumulating the specified cycles-since-new (CSN) in the following Table 1, or rework the existing blades as specified in paragraph (g) of this AD. \n\n\tTable 1.--LP Compressor Fan Blade Replacement or Rework Schedule \n\n\n\nBoeing 777 Series: \nAirplane maximum gross weight (times 1,000 pounds) \nRB211 Trent Engine Model \nReplace or rework LP compressor fan blades before accumulating: \n-300 \n660, 632.5 \n-884, -892, -884B \n2,400 CSN. \n-200 \n656 \n-892, -895 \n2,400 CSN. \n-200 \n648 \n-892, -892B \n3,200 CSN. \n-200 \n632.5 \n-892B \n3,200 CSN. \n-200 \n632.5 \n-892 \n4,100 CSN. \n-200 \n555 \n-884 \n4,100 CSN. \n-200 \n545 \n-877 \n4,100 CSN. \n-200 \n535 \n-875 \n4,100 CSN. \n-200 \n506 \n-875 \n4,100 CSN. \n\n\t(g) Rework LP compressor fan blades at or before accumulating the specified CSN in Table 1 of this AD. Follow paragraphs 3.B.(1) through 3.B.(22) of Accomplishment Instructions of RR service bulletin (SB) No. RB.211-72-E044, Revision 2, dated October 8, 2004, to do the blade rework. \n\n\t(h) For engines moved between configurations, calculate the cycles remaining using either of the following: \n\n\t(1) Subtract the total CSN from the most limiting configuration's limit from Table 1 of this AD; or \n\n\t(2) Calculate the cycles remaining using the following equation: \n\n\n\t\nWhere: \n\nXr = Cycles remaining in current configuration. \nLc = Cyclic limit of current configuration from Table 1 of this AD. \nXn = Cycles accumulated in configuration n. \nLn = Cyclic limit in configuration n from Table 1 of this AD. \n\n\n\t(i) Information on the source life of the cycle limits in Table 1 of this AD can be found in RR Alert SB No. RB.211-72-AE055, Revision 3, dated May 28, 2004. \n\nAlternative Methods of Compliance \n\n\t(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. \n\nMaterial Incorporated by Reference \n\n\t(k) You must use Rolls-Royce plc Service Bulletin No. RB.211-72- E044, Revision 2, dated October 8, 2004, to perform the blade rework 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 from Rolls-Royce plc, PO Box 31, Derby, England, DE248BJ; telephone: 011-44-1332-242424; fax: 011-44-1332-245418. You can review a copy 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 . \n\nRelated Information \n\n\t(l) CAA airworthiness directive G-2004-030, dated December 23, 2004, and RR Alert SB No. RB.211-72-AE055, Revision 4, dated December 9, 2004, pertain to the subject of this AD.

The FAA proposed to amend 14 CFR Part 39 with a new AD, applicable to RR models RB211 Trent 875-17, Trent 877- 17, Trent 884-17, Trent 884B-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines with LP compressor fan blades, P/N FW18548 installed. We published the proposed AD in the Federal Register on May 27, 2005 (70 FR 30653). That action proposed to require LP compressor fan blade replacement with new or previously reworked blades, or rework of the existing LP compressor fan blades, at reduced compliance times from the previous AD, for certain airplane and engine rating combinations and certain maximum gross weight limits. \n\nExamining the AD Docket \n\n\tYou may examine the AD Docket (including any comments and service information), by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for the location. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We considered the one comment received. The commenter supports the proposal. \n\nConclusion \n\n\tWe carefully reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\tAbout 392 RR RB211 Trent 800 series turbofan engines of the affected design are in the worldwide fleet. About 106 engines installed on airplanes of U.S. registry will be affected by this AD. We estimate about 100 work hours per engine are needed to perform blade rework, and that the average labor rate is $65 per work hour. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $689,000. \n\nAuthority for this Rulemaking \n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detailthe scope of the Agency's authority. \n\n\tWe are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, "General requirements." Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\tWe have determined this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. \n\n\tFor the reasons discussed above, I certify that this AD: \n\n\t(1) Is not a "significant regulatory action" under Executive Order 12866; \n\n\t(2) Is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\n\t(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. \n\n\tWe prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include "AD Docket No. 2003-NE-38-AD" in your request. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The FAA amends Sec. 39.13 by removing Amendment 39-13736 (69 FR 44925, August 12, 2004) and by adding a new airworthiness directive, Amendment 39-14404, to read as follows: