Federal Aviation Administration (FAA), DOT.
Notice of proposed rulemaking (NPRM).
The FAA proposes to supersede an existing airworthiness directive (AD) for Rolls-Royce plc (RR) models RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 884B-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines with low pressure (LP) compressor fan blades, part number (P/N) FW18548 installed. That AD currently requires LP compressor fan blade replacement with new or previously reworked blades, or rework of the existing LP compressor fan blades. This proposed AD would require the same actions but at reduced compliance times for certain airplane and engine rating combinations and certain maximum gross weight limits. This proposed AD results from a number of new production LP compressor blades found with surfaces formed outside of design intent. We are proposing this AD to prevent possible multiple uncontained LP compressor fan blade failure, due to cracking in the blade root caused by increased stresses in the shear key slots.
We must receive any comments on this proposed AD by July 26, 2005.
Use one of the following addresses to comment on this proposed AD:
- By mail: Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-NE-38-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
- By fax: (781) 238-7055.
- By e-mail: email@example.com.
You can get the service information identified in this proposed AD from Start Printed Page 30654Rolls-Royce plc, PO Box 31, Derby, England, DE248BJ; telephone: 011-44-1332-242424; fax: 011-44-1332-245418.
You may examine the AD docket, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine And Propeller Directorate, 12 New England Executive Park; Burlington, MA 01803-5299; telephone (781) 238-7175; fax (781) 238-7199.End Further Info End Preamble Start Supplemental Information
We invite you to send any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2003-NE-38-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 proposed AD. If a person contacts us verbally, and that contact relates to a substantive part of this proposed 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 proposed 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 for the location.
On July 14, 2004, we issued AD 2004-15-02, Amendment 39-13736 (69 FR 44925, July 28, 2004). That AD requires LP compressor fan blade replacement with new or previously reworked blades, or rework of the existing LP compressor fan blades. The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (U.K.), notified the FAA that an unsafe condition may exist on Rolls-Royce plc RB211 Trent 800 Series turbofan engines. The CAA advises that RR has introduced revised rework lives for LP compressor fan blades, P/N FW18548, in redefined airplane and engine rating combinations. These rating combinations also take into account the airplane gross weight.
Relevant Service Information
We have reviewed and approved the technical contents of RR Service Bulletin (SB) No. RB.211-72-E044, Revision 2, dated October 8, 2004, that describes procedures for inspecting and reworking LP compressor fan blades P/N FW18548, that utilize the shear key blade retention device. The CAA classified this service bulletin as mandatory and issued AD G-2004-0030, dated December 23, 2004, in order to ensure the airworthiness of these RB211 Trent 800 series turbofan engines in the U.K.
Bilateral Agreement Information
This engine model is manufactured in the U.K. 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. In keeping with this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. We have 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 and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. Therefore, we are proposing this AD, which would require at or before the accumulation of certain cycles-since-new based on airplane and engine rating combinations and airplane gross weight, replacement of LP compressor fan blades with new or previously reworked LP compressor fan blades, or rework of the existing blades. The proposed AD would require that you do these actions using the service information described previously.
Costs of Compliance
About 392 RR RB211 Trent 800 series turbofan engines of the affected design are in the worldwide fleet. We estimate that this proposed AD would affect 106 engines installed on airplanes of U.S. registry. We also estimate that about 100 work hours per engine are needed to perform blade rework, and that the average labor rate is $65 per work hour. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $689,000.
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.
We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.
For the reasons discussed above, I certify that the proposed 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. Would 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 comply with this proposal 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. 2003-NE-38-AD” in your request.Start List of Subjects
List of Subjects in 14 CFR Part 39End List of Subjects
The Proposed Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 14 CFR part 39 as follows:Start Part Start Printed Page 30655
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. The FAA amends § 39.13 by removing Amendment 39-13736 (69 FR 44925, July 28, 2004) and by adding a new airworthiness directive, to read as follows:
Rolls-Royce plc: Docket No. 2003-NE-38-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by July 26, 2005.
(b) This AD supersedes AD 2004-15-02, Amendment 39-13736.
(c) This AD applies to Rolls-Royce plc (RR) models RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 884B-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines, with low pressure (LP) compressor fan blades, part number FW18548 installed. These engines are installed on, but not limited to, Boeing 777 series airplanes.
(d) This AD results from a number of new production LP compressor blades found with surfaces formed outside of design intent. We are issuing this AD to prevent possible multiple uncontained LP compressor fan blade failure, due to cracking in the blade root caused by increased stresses in the shear key slots.
(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
Actions Required for LP Compressor Fan Blades
(f) Replace LP compressor fan blades with new or previously reworked LP compressor blades before accumulating the specified cycles-since-new (CSN) in the following Table 1, or rework the existing blades as specified in paragraph (g) of this AD.
|Boeing 777 series||Airplane maximum gross weight (times 1,000 pounds)||RB211 Trent engine model||Replace or rework LP compressor fan blades before accumulating|
|-300||660, 632.5||-884, -892, -884B||2,400 CSN.|
|-200||656||-892, -895||2,400 CSN.|
|-200||648||-892, -892B||3,200 CSN.|
(g) Rework LP compressor fan blades at or before accumulating the specified CSN in Table 1 of this AD. Follow paragraphs 3.B.(1) through 3.B.(22) of Accomplishment Instructions of RR service bulletin (SB) No. RB.211-72-E044, Revision 2, dated October 8, 2004, to do the blade rework.
(h) For engines moved between configurations, calculate the cycles remaining using either of the following:
(1) Subtract the total CSN from the most limiting configuration's limit from Table 1 of this AD; or
(2) Calculate the cycles remaining using the following equation:
X r = Cycles remaining in current configuration.
L c = Cyclic limit of current configuration from Table 1 of this AD.
X n = Cycles accumulated in configuration n.
L n = Cyclic limit in configuration n from Table 1 of this AD.
(i) Information on the source life of the cycle limits in Table 1 of this AD can be found in RR Alert SB No. RB.211-72-AE055, Revision 3, dated May 28, 2004.
Alternative Methods of Compliance
(j) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.
(k) CAA airworthiness directive G-2004-030, dated December 23, 2004, and RR Alert SB No. RB.211-72-AE055, Revision 4, dated December 9, 2004, pertain to the subject of this AD.
Issued in Burlington, Massachusetts, on May 23, 2005.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification Service.
[FR Doc. 05-10635 Filed 5-26-05; 8:45 am]
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