AD 2001-19-06

This amendment adopts a new airworthiness directive (AD) that is applicable to Rolls-Royce plc (RR) Dart 525, 525F, 528, 528D, 529, 529D, 530, 532, 535, 542, and 552 series turboprop engines. This action requires the removal of certain part number (P/N) high pressure turbine (HPT) discs and replacement with serviceable discs. This \namendment is prompted by three reports of uncontained HPT disc failures and the manufacturer's investigation into disc failure. The actions specified in this AD are intended to prevent HPT disc failure, which could result in an uncontained engine failure and damage to the airplane.

Final rule; request for comments

2001-19-06 Rolls-Royce plc: Amendment 39-12446. Docket 2001-NE-29-AD. \n\nApplicability \n\n\tThis airworthiness directive (AD) is applicable to Rolls-Royce Dart 525, 525F, 528-7E, 528D-7E, 529-7E, 529D-7E, 529-7H, 529D-7H, 529-8E, 529D-8E, 529-8H, 529D-8H, 529-8X, 529D-8X, 529-8Y, 529D-8Y, 529-8Z, 529D-8Z, 530, 532-7, 532-7L, 532-7N, 532-7P, 532-7R, 535-2, 535-7R, 542-10, 542-10J, 542-10K, 542-4, 542-4K, 552-2, 552-7, 552-7R series turbofan engines that contain high pressure turbine (HPT) discs having the part numbers listed in the following Table 1: \n\nTable 1.--Part Numbers of Applicable HPT Discs\n\n\n\tThese engines are installed on, but not limited to BAC Viscount Type 810 aircraft, Fokker F.27 Friendship Mark 200, 400, 500, and 600 series aircraft, Maryland Air Industries, Inc. Fairchild F-27A, F, G, M, J, FH-227, FH-227B, C, D, and E series aircraft, Gulfstream Aerospace Model G-159 aircraft, BAE SYSTEMS (Operations) Limited HS 748 series aircraft, Mitsubishi Heavy Industries,Ltd. YS-11 series aircraft, and Convair CV600/640 series aircraft. \n\n\tNote 1: This 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 (d) 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. \n\nCompliance \n\n\tCompliance with this AD is required as indicated, unless already done. \n\n\tTo prevent HPT disc failure, which could result in an uncontained engine failure and damage to the airplane, do the following: \n\n\t(a) Remove from service the discs listed by part number in Table 1 of this AD, in accordance with the following Table 2 of this AD: \n\n\nIf:\nThen:\n(1) Engine is fitted with a listed HPT disc with more than 15,000 cycles since new (CSN) on effective date of this AD. \nRemove from service and replace with a serviceable disc within 300 cycles or before June 30, 2002, whichever occurs earlier.\n(2) Engine is fitted with a listed HPT disc that has 12,000 CSN to 15,000 CSN on effective date of this AD. \nRemove from service and replace with a serviceable disc within 600 cycles or before June 30, 2002, whichever occurs earlier.\n(3) Engine is fitted with a listed HPT disc that has 9,000 to 11,999 CSN on effective date of this AD. \nRemove from service and replace with a serviceable disc within 900 cycles.\n(4) Engine is fitted with a listed HPT disc that has more than 6,000 CSN as of June 30, 2003.Before further flight, remove from service and replace with a serviceable disc.\n(5) Engine is fitted with a listed HPT disc as of June 30, 2004. \nBefore further flight, remove from service and replace with a serviceable disc.\n\n\t(b) Remove from service any discs, listed by part number in Table 1 of this AD, from engines that are returned for a shop visit for any reason. \n\nDefinitions \n\n\t(c) For the purpose of this AD, a serviceable disc is one whose P/N is not listed in Table 1 of this AD. Information on the reworking of affected discs into serviceable discs is specified in Rolls-Royce Dart Service Bulletin Da72-533 Revision 2, dated July 25, 2001. \n\nAlternative Methods of Compliance \n\n\t(d) 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 (ECO). Operators must submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO. \n\n\tNote 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO. \n\nSpecial Flight Permits \n\n\t(e) 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 airplane to a location where the requirements of this AD can be accomplished. \n\n\tNote 3: The subject of this AD is addressed in Civil Airworthiness Authority airworthiness directive AD 007-02-2001, dated April 12, 2001. \n\nEffective Date of this AD \n\n\t(f) This amendment becomes effective on October 15, 2001.

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified the FAA that an unsafe condition may exist on RR Dart 525, 525F, 528, 528D, 529, 529D, 530, 532, 535, 542, and 552 series turboprop engines. The CAA advises that three reports of uncontained HPT disc failures have occurred on in-service engines. The results of an investigation reveal that fretting, wear, and open clearance between the HPT disc diaphragm seal arm and intermediate pressure turbine (IPT) disc diaphragm seal arm can result in a high-response disc vibration mode, which results in high-cycle-fatigue (HCF) fractures in the HPT disc. The manufacturer, through testing, has shown that by adding an interference fit between the HPT and IPT seal arms, the discs become effectively preloaded against each other, significantly reducing disc diaphragm vibratory stresses. This condition, if not corrected, could result in HPT disc failure, which could result in an uncontained engine failure and damage to the airplane. \n\nBilateral Airworthiness Agreement \n\n\tThis engine model is manufactured in the UK, and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States. \n\nFAA's Determination of an Unsafe Condition and Proposed Actions \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other Rolls-Royce plc Dart 525, 525F, 528, 528D, 529, 529D, 530, 532, 535, 542, and 552 series turboprop engines of the same type design, this AD is being issued to prevent HPT disc failure, which could result in an uncontained engine failure and damage to the airplane. This AD requires the scheduled replacement of HPT discs of the affected design with serviceable discs. The cycles and calendar dates of the replacement schedule are based on risk analysis and the need for owners/operators to have an adequate length of time to accomplish this AD. \n\nImmediate Adoption of This AD \n\n\tSince a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\tAlthough this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. \n\n\tComments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD willbe filed in the Rules Docket. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2001-NE-29-AD." The postcard will be date stamped and returned to the commenter. \n\nRegulatory Impact \n\n\tThis final rule does not have federalism implications, as defined in Executive Order 13132, because it would 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. Accordingly, the FAA has not consulted with state authorities prior to publication of this final rule. \n\n\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption ADDRESSES. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n\t1. 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\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: