AD 2000-24-26

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Rolls-Royce plc RB211 Trent 800 series turbofan engines, that currently requires initial and repetitive ultrasonic inspections of fan blade roots for cracks, and replacement, if necessary, with serviceable parts. This amendment requires the reduction of the initial cyclic compliance threshold and repetitive inspection intervals. This amendment also allows inspections to be accomplished within 100 cycles-in-service if the initial or repetitive thresholds are exceeded on the effective date of this AD. This amendment is prompted by an improved understanding of the crack propagation mechanism and the latest service operational data. The actions specified by this AD are intended to detect and prevent fan blade failure, which could result in multiple fan blade releases, uncontained engine failure, and possible damage to the airplane.

Final rule

2000-24-26 Rolls-Royce plc.: Amendment 39-12033. Docket 98-ANE-33-AD. Supersedes AD 98-19-21, Amendment 39-10762.

Applicability: Rolls-Royce plc (RR) RB211 Trent 875, RB211 Trent 877, RB211 Trent 884, RB211 Trent 892, and RB211 Trent 892B series turbofan engines, except if the fan blades described in RR Service Bulletin (SB) RB.211-72-C629 were installed as complete sets. These engines are on installed on but not limited to Boeing 777 series airplanes.

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 (b) of this AD. The request should include an assessmentof 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 fan blade failure, which could result in multiple fan blade releases, uncontained engine failure, and possible damage to the airplane, accomplish the following:

Ultrasonic Inspections (Reduced Thresholds and Repetitive Intervals)
(a) Perform initial and repetitive inspections of fan blade roots for cracks, in accordance with RR SB No. RB211-72-C445, Revision 6, dated September 3, 1999, as follows:

(1) For Trent 875 series engines, inspect as follows:
(i) Initially, prior to accumulating 3,000 cycles-since-new (CSN).
(ii) Thereafter, at intervals not to exceed 400 cycles-in-service (CIS) since last inspection.

(2) For Trent 877 series engines, inspect as follows:
(i) Initially, prior to accumulating 2,000 CSN.
(ii) Thereafter, at intervals not to exceed 350 CIS since last inspection.

(3) For Trent 884 series engines, inspect as follows:
(i) Initially, prior to accumulating 1,500 CSN.
(ii) Thereafter, at intervals not to exceed 350 CIS since last inspection.

(4) For Trent 892 and 892B series engines, inspect as follows:
(i) Initially, prior to accumulating 900 CSN.
(ii) Thereafter, at intervals not to exceed 200 CIS since last inspection.

Engines Exceeding Thresholds and Repetitive Intervals
(5) For engines that exceed the initial inspection thresholds listed in paragraphs (a)(1)(i), (a)(2)(i), (a)(3)(i), and (a)(4)(i) on the effective date of this AD, conduct initial inspection within 100 CIS after the effective date of this AD.

(6) For engines that exceed the repetitive inspection intervals listed in paragraphs (a)(1)(ii), (a)(2)(ii), (a)(3)(ii), and (a)(4)(ii) on the effective date of this AD, inspect within 100 CIS after the effective date of this AD.

Cracked Parts
(7) Prior to further flight, remove from service cracked fan blades and replace with serviceable parts.

Alternate Method of Compliance
(b) 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 shall 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 AD, if any, may be obtained from the ECO.

Ferry Flights
(c) 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 inspection requirements of this AD can be accomplished.

Incorporation by Reference Material
(d) The actions required by this AD must be done in accordance with the following Rolls-Royce SB:

Document No.
Pages
Revision
Date
RB.211-72-C445
1-9
6
September 3, 1999
Appendix 1
1
Original
February 13, 1998

2
6
September 3, 1999

3-4
Original
February 13, 1998
Appendix 2
1
Revision 4
November 6, 1998

2-3
Original
February 13, 1998
Total pages: 16

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 North America, Inc., 2001 South Tibbs Ave., Indianapolis, IN 46241; telephone: (317) 230-3995; fax: (317) 230-4743. Copies may be inspected at the FAA, New England Region, Office of the

Regional Counsel, 12 New England Executive Park, Burlington, MA 01803-5299; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

Effective Date
(e) This amendment becomes effective on February 12, 2001.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 98-19-21, Amendment 39-10762 (63 FR 50484, September 22, 1998, corrected by 63 FR 52961, October 2, 1998), applicable to Rolls-Royce plc (RR) RB211 Trent 800 series turbofan engines, was published in the Federal Register on December 3, 1999 (64 FR 67806). That action proposed to require the reduction of initial compliance thresholds and repetitive cyclic inspection intervals. The action also proposed the allowance for inspections to be accomplished within 100 cycles-in-service if the initial or repetitive thresholds are exceeded on the effective date of the AD.

Comments Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the one comment received. Request to Revise Economic Analysis

The comment states that all RR Trent 800 series engines on the US registry that will be affected by the AD have already been modified to RR Service Bulletin RB.211-72-C629. Therefore, the estimate of the total cost impact of the proposed action on US operators is zero.

The FAA disagrees. Although some Trent 800 series engines on US registered airplanes may have already been modified to RR Service Bulletin RB.211-72-C629 and the actual cost may be reduced, the original economic analysis is retained.

Conclusion
After careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Regulatory Impact
This rule does not have federalism implications, as defined in Executive Order (EO) 13132, because it does 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 rule.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under EO 12866; (2) is not a "significant rule" under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 (FAA) 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.

39.13 [Amended]
2. Section 39.13 is amended by removing Amendment 39-10762 (63 FR 50484, September 22, 1998) and by adding a new airworthiness directive, Amendment 39-12033, to read as follows: