06-1965. Airworthiness Directives; Rolls-Royce plc Models RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 Turbofan Engines

AGENCY:

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

ACTION:

Final rule; request for comments.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce plc (RR) models RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines. This AD requires initial and repetitive borescope inspections of the high pressure-intermediate pressure (HP-IP) turbine bearing internal oil vent tube, scavenge tube, and tube heat shields for wear and cracking, and removing tubes from service if found with any cracks beyond serviceable limits. This AD also requires installation of a new or modified HP-IP turbine bearings support as terminating action for the repetitive borescope inspections. This AD results from two reports of RR RB211 Trent 700 series engines found with the HP-IP internal oil vent tube and scavenge tube fretted by damaged heat shields on the tubes. We are issuing this AD to prevent oil ejecting from the HP-IP turbine bearings chamber and igniting. Burning oil can cause the intermediate pressure (IP) shaft to fracture, the IP turbine to overspeed, and possible uncontained failure of the engine.

DATES:

Effective March 27, 2006. The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of March 27, 2006.

We must receive any comments on this AD by May 5, 2006.

ADDRESSES:

Use one of the following addresses to comment on this AD:

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Rolls-Royce plc, PO Box 31, Derby, England, DE248BJ; telephone: [phone]; fax: [phone], for the service information identified in this AD.

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 [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified us that an unsafe condition might exist on RR RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines. The CAA advises that two RB211 Trent 700 series engines were removed due to high oil consumption. Investigation revealed that damaged heat shields caused fretting of the HP-IP internal oil vent tube and scavenge tube. A previous service incident revealed that ingestion of HP cooling air into either the scavenge tube or the vent tube can over pressurize the HP-IP turbine bearing chamber. The overpressure can cause oil to eject from the rear of the chamber. If the ejected oil ignites, the fire can trigger fracture of the IP shaft, overspeed of the IP turbine, and uncontained engine failure.

Relevant Service Information

We have reviewed and approved the technical contents of RR Alert Service Bulletin RB.211-72-AE792, dated July 8, 2005, that describes procedures for initial and repetitive borescope inspections of the HP-IP turbine bearing internal oil vent tube, scavenge tube, and tube heat shields for wear and cracking. We have also reviewed and approved the technical contents of RR Service Bulletin RB.211-72-E708, Revision 2, dated September 6, 2005, that describes procedures for installing a new or modified HP-IP turbine bearings support. The CAA classified these service bulletins as mandatory and issued AD G-2005-0016 in order to ensure the airworthiness of these RR RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines in the UK.

Bilateral Airworthiness Agreement

These RR RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines are manufactured in the UK and are 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. Under this bilateral airworthiness agreement, the CAA 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 This AD

Although no airplanes that are registered in the United States use these RR RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines, the possibility exists that the engines could be used on airplanes that are registered in the United States in the future. The unsafe condition described previously is likely to exist or develop on other RR RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines of the same type design. We are issuing this AD to prevent oil ejecting from the HP-IP turbine bearings chamber and igniting. Burning oil can cause the IP shaft to fracture, the IP turbine to overspeed, and possible uncontained failure of the engine. This AD requires:

• Initial and repetitive borescope inspections of the HP-IP turbine bearing internal oil vent tube, scavenge tube, and tube heat shields for wear and cracking; and
• Removing tubes from service if found with any cracks beyond serviceable limits; and
• As terminating action to the repetitive inspections required by the AD, at the next IP (05) module overhaul, but before May 31, 2010, removing the HP-IP bearings support introduced prior to Rolls-Royce Modification 72-E708, and replacing with serviceable parts.

You must use the service information described previously to perform the actions required by this AD.

FAA's Determination of the Effective Date

Since there are currently no domestic operators of this engine model, notice and opportunity for public comment before issuing this AD are unnecessary. 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 send us any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. FAA-2006-23605; Directorate Identifier 2005-NE-48-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it.

We will post all comments we receive, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of the DMS Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.

Examining the AD Docket

You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.

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 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 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 comply with this AD and placed it in the AD Docket.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

Under 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

2006-05-03 Rolls-Royce plc: Amendment 39-14500. Docket No. FAA-2006-23605; Directorate Identifier 2005-NE-48-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective March 27, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Rolls-Royce plc (RR) models RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines. These engines are installed on, but not limited to, Airbus A330-243, A330-341, A330-342, and A330-343 airplanes.

Unsafe Condition

(d) This AD results from two reports of RR RB211 Trent 700 series engines found with the high pressure-intermediate pressure (HP-IP) internal oil vent tube and scavenge tube fretted by damaged heat shields on the tubes. Burning oil can cause the intermediate pressure (IP) shaft to fracture, the IP turbine to overspeed, and possible uncontained failure of the engine. We are issuing this AD to prevent oil ejecting from the HP-IP turbine bearings chamber and igniting.

Compliance

(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.

Initial Borescope Inspection

(f) Perform an initial borescope inspection of the HP-IP turbine bearing internal oil vent and scavenge tubes and tube heat shields before the thresholds listed in Table 1 of this AD, or within 4 months after the effective date of this AD, whichever occurs later. To do the inspections, use either the on-wing or the in-shop inspection procedures in the Accomplishment Instructions of RR Alert Service Bulletin (ASB) RB.211-72-AE792, dated July 8, 2005.

Table 1.—Inspection Criteria

Action	Inspection threshold
(1) Initial inspection	10,000 hours time-since-new (TSN) or time-since-overhaul (TSO), or 2,500 cycles-since-new (CSN) or cycles-since-overhaul (CSO), whichever occurs first.
(2) Repetitive inspection interval for tubes with no visible damage to outer heat shields on the tubes	10,000 hours time-since-last-inspection (TSLI), or 2,500 cycles-since-last-inspection (CSLI), whichever occurs first.
(3) Repetitive inspection interval for tubes with cracking up to 90 degrees around tube circumference or 10 millimeters along the length of either outer heat shield	6,400 hours TSLI or 1,600 CSLI, whichever occurs first.
(4) Repetitive inspection interval for tubes with cracking greater than (3) above, but less than 360 degrees around the tube circumference	1,600 hours TSLI or 400 CSLI, whichever occurs first.

Repetitive Borescope Inspections

(g) Repeat the borescope inspections of the HP-IP turbine bearing internal oil vent and scavenge tubes within the applicable intervals listed in Table 1 of this AD. To do the inspections, use either the on-wing or the in-shop inspection procedures in the Accomplishment Instructions of RR ASB RB.211-72-AE792, dated July 8, 2005.

Removal of Damaged Tubes

(h) Within 10 CSLI, remove tubes with cracking around the complete circumference of either outer heat shield, or if any material is missing from either outer heat shield, or if either tube is fretted by loose heat shield material.

Terminating Action

(i) As terminating action to the repetitive inspections required by paragraph (g) of this AD, at the next IP (05) module overhaul, but before May 31, 2010, remove the HP-IP bearings supports introduced prior to Rolls-Royce Modification 72-E708 and replace with serviceable parts. Information on Rolls-Royce Modification 72-E708 can be found in RR Service Bulletin RB.211-72-E708, Revision 2, dated September 6, 2005.

Definition

(j) For the purposes of this AD, serviceable parts are new or reworked bearings supports which reduce the adverse effects of HP3 cooling air turbulence on the HP-IP turbine bearing internal oil vent and scavenge tubes and tube heat shields, as described in Rolls-Royce Modification 72-E708.

Alternative Methods of Compliance

(k) 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.

Related Information

(l) Civil Aviation Authority airworthiness directive G-2005-0016, dated July 6, 2005, also addresses the subject of this AD.

Material Incorporated by Reference

(m) You must use the service information specified in Table 2 of this AD to perform the inspections and installations required by this AD. The Director of the Federal Register approved the incorporation by reference of the documents listed in Table 2 of this AD in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Rolls-Royce plc, PO Box 31, Derby, England, DE248BJ; telephone: [phone]; fax: [phone], for a copy of this service information. You may review copies at the Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001, on the Internet at http://dms.dot.gov; 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.

Table 2.—Incorporation by Reference

Service Bulletin No.	Page	Revision	Date
RB.211-72-AE792	All	Original	July 8, 2005.
Total Pages: 22
Appendix A of RB.211-72-AE792	All	Original	July 8, 2005.
Total Pages: 3

Issued in Burlington, Massachusetts, on February 24, 2006.

Peter A. White,

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