On August 1, 2001, we issued AD 2001-16-05, Amendment 39-12373 (66 FR 42105, August 10, 2001). That AD requires initial ultrasonic inspections of the fan blade root with blades removed, repetitive ultrasonic inspections of the fan blade root with blades removed or installed, and ultrasonic inspections to be done with the fan blades removed at least every third inspection. That AD resulted from reports of fan blade failures due to dovetail root cracks. That condition, if not corrected, could result in possible multiple LPC fan blade failures, uncontained engine failure, and damage to the airplane.
Actions Since AD 2001-16-05 Was Issued
Since that AD was issued, analysis of flight data returned to RR shows a need for consistent inspection thresholds for all engine models. The actions specified in this AD are intended to prevent possible multiple LPC fan blade failures, which could result in an uncontained engine failure and damage to the airplane.Special Flight Permits Paragraph Removed
Paragraph (g) of the current AD, AD 2001-16-05, contains a paragraph pertaining to special flight permits. Even though this final rule does not contain a similar paragraph, we have made no changes with regard to the use of special flight permits to operate the airplane to a repair facility to do the work required by this AD. In July 2002, we published a new Part 39 that contains a general authority regarding special flight permits and airworthiness directives; see Docket No. FAA-2004-8460, Amendment 39-9474 (69 FR 47998, July 22, 2002). Thus, when we now supersede ADs we will not include a specific paragraph on special flight permits unless we want to limit the use of that general authority granted in section 39.23.
Relevant Service Information
We have reviewed and approved the technical contents of RR Mandatory Service Bulletin (MSB) No. RB.211-72-C878, Revision 7, dated December 5, 2003, that:
Removes LPC fan blades and performs initial and repetitive ultrasonic inspections for cracks in LPC fan blade dovetail roots, at earlier initial thresholds than the inspections required by the current AD, and, at adjusted repetitive inspection intervals from the current AD.
Provides a procedure that does not require blade removal from the engine in order to perform repetitive ultrasonic inspections for cracks in LPC fan blade dovetail roots.
Bilateral Airworthiness Agreement
This engine model is manufactured in the United Kingdom 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 Civil Aviation Authority (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 Proposed Actions
Although none of these affected engine models are used on any airplanes that are registered in the United States, the possibility exists that the engine models could be used on airplanes that are registered in the United States in the future. Since an unsafe condition has been identified that is likely to exist or develop on other RR RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engine models of the same type design, this AD is being issued to prevent possible multiple LPC fan blade failures, which could result in an uncontained engine failure and damage to the airplane. This AD requires:
Initial ultrasonic inspections of the fan blade root with blades removed; at or before accumulating 1,100 cycles-since-new (CSN) on the fan blades after the effective date of the AD; and
For blades with more than 1,100 CSN that have not been previously inspected, initial ultrasonic inspections of the fan blade root with blades removed; within 300 cycles-in-service (CIS) from the effective date of the AD or within 2,000 CSN, whichever occurs first; and
Repetitive ultrasonic inspections of the fan blade root, with blades removed within 300 CIS intervals, or with blades not removed within 250 CIS intervals.
The actions are required to be done using the service bulletin described previously.
Immediate Adoption of This AD
Since there are currently no domestic operators of these engine models, notice and opportunity for prior public comment are unnecessary. Therefore, a situation exists that allows the immediate adoption of this regulation.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "AD Docket No. 2000-NE-05-AD" in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it. If a person contacts us verbally, and that contact relates to a substantive part of this AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the AD in light of those comments.
Examining the AD Docket
You 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 forthe location.
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 have determined that this AD will not have federalism implications under Executive Order13132. 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 that the regulation:
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 summary of the costs to satisfy the initial requirements of 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. 2000-NE-05-AD" in your request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the 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.
Sec. 39.13 [Amended]
2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by removing Amendment 39-12373 (66 FR 42105, August 10, 2001), and by adding a new airworthiness directive (AD), Amendment 39-13941, to read as follows: