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Airworthiness Directives; Rolls-Royce plc RB211-524 Series Turbofan Engines

Document Details

Information about this document as published in the Federal Register.

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AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Recently an RB211 HP turbine disc has been found with a crack which had propagated further than expected from the risk model that was used to establish the original inspection.

We are issuing this AD to detect cracks that could cause the high pressure (HP) turbine disc to fail and result in uncontained failure of the engine.

DATES:

This AD becomes effective September 15, 2008. The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of September 15, 2008.

ADDRESSES:

The Docket Operations office is located at Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Jason Yang, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: jason.yang@faa.gov; telephone (781) 238-7747; fax (781) 238-7199.

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SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on October 24, 2007 (72 FR 60293). That NPRM proposed to correct an unsafe condition for the specified products. The Civil Aviation Authority (CAA), which is the aviation authority for the United Kingdom, has issued United Kingdom Airworthiness Directive G-2006-0002, dated February 13, 2006, to correct an unsafe condition for the specified products. The CAA AD states:

A population of HP turbine discs that were manufactured between 1989-1999 and which were subject to possible machining anomalies, were believed to have an increased chance of suffering from cooling air hole cracking, compared to the general fleet population of HP turbine discs. As a result of this risk, Rolls-Royce issued Non-Modification Service Bulletin (NMSB) 72-C816, recommending in-service inspections of the subject discs.

Recently an RB211 HP turbine disc has been found with a crack which had propagated further than expected from the risk model that was used to establish the original inspection defined in the above NMSB; This has led to the need for a revision of the original inspection requirements.

An HP turbine disc fracture would be uncontained and create a potential unsafe condition. Accordingly, this AD introduces revised inspection requirements to reflect the increased risk of HP turbine disc cracking and potential disc fracture.

You may obtain further information by examining the CAA AD in the AD docket.

Comments

We gave the public the opportunity to participate in developing this AD. We considered the comment received. The commenter supports the NPRM.

Editorial Change for Clarity

We changed the paragraph layering in paragraph (e) of the regulatory text to clarify the requirements for disks that have a serial number in Table 1 of this AD and disks that don't have a serial number in Table 1 of this AD.

Conclusion

We reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD with the change described previously. We determined that this change will not increase the economic burden on any operator or increase the scope of the AD.

Costs of Compliance

We estimate that this AD will affect 72 engines of U.S. registry. We also estimate that it will take about 10 work-hours per product to comply with this AD. The average labor rate is $80 per work-hour. Required parts will cost about $15,000 per product. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $1,137,600. Our cost estimate is exclusive of possible warranty coverage.

Authority for This Rulemaking

Title 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 detail the scope of the Agency's authority.

We 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.

Regulatory Findings

We determined that 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.

For the reasons discussed above, I certify this AD:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

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.

We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​ or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is provided in the ADDRESSES section. Comments will be Start Printed Page 46551available in the AD docket shortly after receipt.

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List of Subjects in 14 CFR Part 39

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Adoption of the Amendment

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Accordingly, under the authority delegated to me by the Administrator, the FAA amends

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PART 39—AIRWORTHINESS DIRECTIVES

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

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

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[Amended]
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2. The FAA amends § 39.13 by adding the following new AD:

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2008-16-18 Rolls-Royce plc: Amendment 39-15636. Docket No. FAA-2007-0036; Directorate Identifier 2007-NE-22-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective September 15, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Rolls-Royce (RR) RB211-524 series turbofan engines with certain high pressure (HP) turbine discs installed. These engines are installed on, but not limited to, Boeing 747 series and 767 series airplanes and Lockheed L1011 series airplanes.

Reason

(d) Recently an RB211 HP turbine disc has been found with a crack which had propagated further than expected from the risk model that was used to establish the original inspection.

We are issuing this AD to detect cracks that could cause the HP turbine disc to fail and result in uncontained failure of the engine.

Actions and Compliance

(e) Unless already done, do the following actions.

(1) Carry out the eddy current inspection as detailed in Section 3—Accomplishment Instructions of Rolls-Royce NMSB RB.211-72-AE718, dated January 24, 2006.

(2) Carry out the eddy current inspection in accordance with the following schedule:

(i) The HP disc serial numbers listed in Table 1 are to be inspected as follows:

Table 1—HP Disc Serial Numbers by Part Number

Part No.Serial No.
UL29473LAQDY6043
UL29473LAQDY6048
UL29473LAQDY6079
UL29473LDRCZ10057
UL29473LDRCZ10264
UL29473LDRCZ10415
UL29473LDRCZ11402
UL29473LDRCZ11425
UL29473LDRCZ11497
UL29473LDRCZ11663
UL29473LDRCZ11679
UL29473LDRCZ12301
UL29473LDRCZ12308
UL29473LDRCZ12316
UL29473LDRCZ12319
UL29473LQDY6957
UL29473LQDY9075
UL29473LQDY9084
UL29473LQDY9557
UL29473LQDY9906
UL29473LQDY9956
UL29473LQDY9970
UL29473LQDY9985
UL29472LQDY9125
UL29472LQDY9554
UL29472LQDY9582
UL29472LQDY9895
UL29472LQDY9910
UL29472LQDY9947
UL29472LQDY9960
UL24994LQDY6777
UL24994LQDY6792
UL24994LQDY6859
UL24994LQDY6860
UL24994LQDY6866
UL24994LQDY6869
UL24994LQDY6934
UL24994LQDY6946
UL24994LQDY6963
UL23166LQDY6745
UL23166LQDY6846
UL23166LQDY6848
UL23166LQDY6954
FK24790LDRCZ12492
FK24790LDRCZ12694

(A) For all RB211-524 engine marks except RB211-524D4 variants:

(1) If the HP turbine disc cycles are greater than 6150 cycles since new on the effective date of this AD, inspect the HP turbine disc within 500 cycles after the effective date of this AD.

(2) If the HP turbine disc cycles are less than 6150 cycles since new on the effective date of this AD, inspect the disc by whichever is the soonest of the conditions below:

(i) Prior to reaching 6650 cycles since new. The HP turbine disc life at inspection must be greater than 700 cycles since new.

(ii) At next shop visit where the HP turbine rotor is removed from the Combustor Outer Case and the HP turbine disc life is greater than 700 cycles since new. If a HP turbine disc that meets these cyclic life criteria is currently at shop visit, and if, at the effective date of this Airworthiness Directive, it has not yet been reinstalled into the Combustion Outer Case, then the HP turbine disc must be inspected in accordance with the requirements of this Airworthiness Directive at the current shop visit.

(B) For all RB211-524D4 engine mark variants:

(1) If the HP turbine disc cycles are greater than 5000 cycles since new on the effective date of this AD, inspect the HP turbine disc within 500 cycles after the effective date of this AD.

(2) If the HP turbine disc cycles were less than 5000 cycles since new on the effective date of this AD, inspect the HP turbine disc by whichever is the soonest of the conditions below:

(i) Prior to reaching 5500 cycles since new. The HP turbine disc life at inspection must be greater than 700 cycles since new.

(ii) At the next shop visit where the HP turbine rotor is removed from the Combustor Outer Case and the HP turbine disc life is greater than 700 cycles since new. If a HP turbine disc that meets these cyclic life criteria is currently at shop visit, and if, at the effective date of this Airworthiness Directive, it has not yet been reinstalled into the Combustion Outer Case, then the HP turbine disc must be inspected in accordance with the requirements of this Airworthiness Directive at the current shop visit.

(ii) For all other HP turbine discs specified in the Applicability of this Directive but not listed in Table 1 of this AD.

(A) Inspect the HP turbine disc at next shop visit where the HP turbine rotor is removed from the Combustor Outer Case and the HP turbine disc life is greater than 700 cycles since new. If a HP turbine disc that meets these cyclic life criteria is currently at shop visit, and if, at the effective date of this Airworthiness Directive, it has not yet been reinstalled into the Combustion Outer Case, then the HP turbine disc must be inspected in accordance with the requirements of this Airworthiness Directive at the current shop visit.

(B) If a HP turbine disc has previously passed the inspection to Rolls-Royce NMSB 72-C816 or the focused inspection carried out in accordance with Rolls-Royce TS594-J Overhaul Process Manual Task 70-00-00-200-223 at greater than 700 cycles since new, then either of these inspections meets the requirements of this Airworthiness Directive.

FAA AD Differences

(f) Wherever the MCAI AD specifies 24 November 2005, this AD specifies the effective date of this AD.

Other FAA AD Provisions

(g) Alternative Methods of Compliance (AMOCs): The Manager, Engine Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Related Information

(h) Refer to the Civil Aviation Authority Airworthiness Directive G-2006-0002, dated February 13, 2006, for related information.

(i) Contact Jason Yang, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: jason.yang@faa.gov; telephone (781) 238-7747; fax (781) 238-7199, for more information about this AD. Start Printed Page 46552

Material Incorporated by Reference

(j) You must use Rolls-Royce Service Bulletin RB.211-72-AE718, dated January 24, 2006, to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) For service information identified in this AD, contact Rolls-Royce plc, PO Box 31, Derby, England; telephone: 011 44 1332-242424; fax: 011 44 1332-249936.

(3) You may review copies at the FAA, New England Region, 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.

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Issued in Burlington, Massachusetts, on July 31, 2008.

Peter A. White,

Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.

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[FR Doc. E8-18102 Filed 8-8-08; 8:45 am]

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