Airworthiness Directives; Rolls-Royce, plc. Models Tay 650-15 and 651-54 Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) that is applicable to Rolls-Royce, plc (RR) models Tay 650-15 and 651-54 turbofan engines. This action requires borescope inspection of the high pressure compressor (HPC) stage 12 disc assembly to detect damage caused by HPC outlet guide vane (OGV) retaining bolt failure, and replacement of unserviceable parts with serviceable parts. This action also requires as terminating action, the incorporation of a new design retention arrangement for the HPC OGV, to prevent HPC OGV retaining bolt failure. This amendment is prompted by service reports of cracked HPC stage 11/12 disc spacers. The actions specified in this AD are intended to prevent an uncontained failure of the HPC stage 11/12 disc spacer, which could result in damage to the airplane.

DATES:

Effective February 15, 2002. The incorporation by reference of certain publications listed in the rule is approved by the Director of the Federal Register as of February 15, 2002.

Comments for inclusion in the Rules Docket must be received on or before April 1, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001-NE-02-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. Comments may also be sent via the Internet using the following address: “9-ane-adcomment@faa.gov”. Comments sent via the Internet must contain the docket number in the subject line.

The service information referenced in this AD may be obtained from Rolls-Royce plc, PO Box 31 Derby, DE24 8BJ, United Kingdom; telephone 011-44-1332-242424; fax 011-44-1332-249936. This information may be examined at the FAA, by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays, 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.

FOR FURTHER INFORMATION CONTACT:

Keith Mead, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7744; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

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 models Tay 650-15 and 651-54 turbofan engines. The CAA advises that four cracked HPC stage 11/12 spacers have been found during engine overhaul. Investigation has concluded that the spacer cracking results from prior failures of the HPC OGV retaining bolts. The separated OGV bolt material is released into a cavity between the inner seal support assembly air seal and stage 12 rotor disc assembly, damaging the disc assembly, resulting in high stresses and cracking of the HPC stage 11/12 spacer. Loose object damage resulting from OGV retaining bolt material release is clearly visible during borescope inspection of the stage 12 rotor disc assembly rear face. Based on an engineering review, a redesign has been introduced to reduce the loading on the OGV retaining bolts, introduced by mandatory service bulletin (SB) Tay-72-1498, which is terminating action for this AD.

Manufacturer's Service Information

Rolls-Royce, plc has issued mandatory SB's Tay-72-1483, Revision 2, dated October 20, 2000, Tay-72-1498, dated October 20, 2000, and Tay-72-1498, Revision 1, dated December 1, 2000, that specify procedures for:

• Initial and repetitive borescope inspections, based on bolt cyclic life exposure, of the stage 12 rotor disc assembly for damage due to failed HPC OGV retaining bolts and, if necessary, replacement with serviceable parts.
• Introduction of revised retaining and locking features for the HPC OGV and outer seal spacer, to eliminate stage 12 rotor disc assembly damage and stage 11/12 spacer cracking.

The CAA has classified SB's Tay-72-1483, Revision 2, dated October 20, 2000; and Tay-72-1498, Revision 1, dated December 1, 2000; as mandatory and issued AD 005-12-99, dated December 2, 1999; and AD 003-10-2000, dated December 1, 2000, in order to assure the airworthiness of these RR Tay engines in the UK.

Bilateral Airworthiness Agreement

These engines are manufactured in the UK, and are type certificated for operation in the United States under the provisions of § 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.

FAA's Determination of an Unsafe Condition and Required Actions

Since an unsafe condition has been identified that is likely to exist or develop on other RR models Tay 650-15 and 651-54 turbofan engines of the same type design, this AD is being issued to prevent an uncontained failure of the HPC stage 11/12 disc spacer, which could result in damage to the airplane. This AD requires:

• Initial and repetitive borescope inspections of the stage 12 rotor disc assembly for damage due to failed HPC OGV retaining bolts, and replacement with serviceable parts as required.
• Introduction of revised retaining and locking features for the HPC OGV and outer seal spacer, to eliminate stage 12 rotor disc assembly damage and stage 11/12 spacer cracking due to failed HPC OGV retaining bolts.

The actions must be done in accordance with the service bulletins described previously.

Immediate Adoption of This AD

Since 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. Therefore, a situation exists that allows the immediate adoption of this regulation.

Comments Invited

Although 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.

Comments 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 will be filed in the Rules Docket.

Commenters 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-02-AD.” The postcard will be date stamped and returned to the commenter.

Regulatory Analysis

This 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.

The 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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, 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:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

2. Section 39.13 is amended by adding the following new airworthiness directive:

2002-01-29 Rolls-Royce, plc: Amendment 39-12624. Docket No. 2001-NE-02-AD.

Applicability

This airworthiness directive (AD) is applicable to Rolls-Royce, plc. (RR) models Tay 650-15 and 651-54 turbofan engines with high pressure compressor (HPC) outlet guide vane (OGV) retaining bolts part numbers (P/N's) BLT3602, DU909, and DU818 installed. These engines are installed on, but not limited to Boeing 727 and Fokker F.28 Mark 0100 airplanes.

Note 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 (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

Compliance with this AD is required as indicated, unless already done.

To prevent an uncontained failure of the HPC stage 11/12 disc spacer, which could result in damage to the airplane, do the following:

Initial Inspection

(a) Perform borescope inspection to the rear side of the stage 12 rotor disc in accordance with paragraph 3.A.(1) of the Accomplishment Instructions of RR Mandatory Service Bulletin (SB) Tay-72-1483, Revision 2, dated October 20, 2000, at or before accumulating 8,000 cycles on the OGV retaining bolts, or within 30 days from the effective date of this AD, whichever occurs later. If damage is observed on the stage 12 rotor disc, replace unserviceable parts with serviceable parts as necessary.

Repetitive Inspections

(b) Thereafter, perform repetitive borescope inspections of the rear side of the stage 12 rotor disc no earlier than 1,800 and no later than 2,200 cycles-since-last-inspection, or no later than 18 months since-last-inspection, whichever occurs first, in accordance with paragraph 3.A.(1) of the Accomplishment Instructions of RR mandatory SB Tay-72-1483, Revision 2, dated October 20, 2000. If damage is observed on the stage 12 rotor disc, replace unserviceable parts with serviceable parts as necessary.

OGV Retaining Bolt Replacement

(c) For engines that had OGV bolts replaced with new bolts P/N's BLT3602, DU909, and DU818 as specified in RR SB Tay-72-1484, the initial and repetitive inspection requirements, based on engine cycles-since-bolt installation, are the same as specified in paragraphs (a) and (b) of this AD.

Terminating Action for the Inspections Required by This AD

(d) Before October 1, 2005 for Tay 650-15 engines, and before October 1, 2012 for Tay 651-54 engines, install new design retaining and locking hardware for the HPC OGV and outer seal housing assembly, in accordance with paragraph 3 of the Accomplishment Instructions of RR mandatory SB Tay-72-1498, dated October 20, 2000, or RR mandatory SB Tay-72-1498, Revision 1, dated December 1, 2000. After performing this action, the inspections specified in paragraphs (a) through (c) of this AD are no longer required.

Alternative Methods of Compliance

(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 (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.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

Special Flight Permits

(f) Special flight permits may be issued in accordance with §§ 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 done.

Documents That Have Been Incorporated by Reference

(g) The inspections and replacements must be done in accordance with the following Rolls-Royce plc, mandatory SB's:

The incorporations by reference were 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 plc, PO Box 31 Derby, DE24 8BJ, United Kingdom; telephone 011-44-1332-242424; fax 011-44-1332-249936. Copies may be inspected, by appointment, 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.

Note 3:

The subject of This AD is addressed in Civil Airworthiness Authority airworthiness directives AD 005-12-99, dated December 2, 1999; and AD 003-10-2000, dated December 1, 2000, in order to assure the airworthiness of these RR Tay engines in the UK.

Effective Date of This AD

(h) This amendment becomes effective on February 15, 2002.