2011-27069. Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede an existing airworthiness directive (AD) that applies to all RR model RB211-524G2-T-19, -524G3-T-19, -524H-T-36, and -524H2-T-19; and RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61; RB211-Trent 768-60, 772-60, 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines that have a high-pressure (HP) compressor stage 1 to 4 rotor disc with a part number (P/N) listed in Table 1 of this proposed AD. The existing AD currently requires repetitive inspections of the axial dovetail slots, and follow-on corrective action depending on findings. Since we issued that AD, we determined that the definition of shop visit is too restrictive in the existing AD. This proposed AD would continue to require those repetitive inspections and follow-on corrective actions, and it would change the definition of a shop visit to be less restrictive. We are proposing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, release of uncontained engine debris, and damage to the airplane.

DATES:

We must receive comments on this proposed AD by December 19, 2011.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this AD, contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone: [phone]; fax: [phone] or e-mail from http://www.rolls-royce.com/​contact/​civil_​team.jsp,, or download the publication from https://www.aeromanager.com. You may review copies of the referenced service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (phone: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Alan Strom, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: [phone]; fax: [phone]; e-mail: [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-0562; Directorate Identifier 2009-NE-29-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

On April 12, 2011, we issued AD 2011-09-07, Amendment 39-16669 (76 FR 24793, May 3, 2011), for all RR model RB211-524G2-T-19, -524G3-T-19, -524H-T-36, and -524H2-T-19; and RB211 Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61; RB211 Trent 768-60, 772-60, 772B-60; and RB211 Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. That AD requires initial and repetitive fluorescent penetrant inspections of the HP compressor stage 1 to 4 rotor discs at the first shop visit after accumulating 1,000 cycles-since-new on the stage 1 to 4 rotor discs or at the next shop visit after the effective date of that AD, which ever occurs later. That AD also requires repetitive inspections at every shop visit. That AD resulted from findings of anomalies at the corners of the disc posts during manufacture of stage 1 and stage 2 discs with axial dovetails slots. We issued that AD to detect cracks in the HP compressor stage 1 and stage 2 disc posts, which could result in failure of the disc post and release of HP compressor blades, release of uncontained engine debris, and damage to the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 2011-09-07, Amendment 39-16669 (76 FR 24793, May 3, 2011), we found that the definition of “shop visit” in the AD is too restrictive, in that it would require operators to inspect more often than required to ensure safety. We also found that Alert Service Bulletin (ASB) No. RB.211-72-AF964, Revision 2, dated June 8, 2011, also may be appropriate to the corrective action in that AD, as is ASB No. RB.211-72-AF964, Revision 1, dated June 6, 2008 which is referenced in AD 2011-09-07.

Relevant Service Information

We reviewed RR ASB No. RB.211-72-AF964, Revision 1, dated June 6, 2008, and Revision 2, dated June 8, 2011. The ASB describes procedures for cleaning and inspecting the axial dovetail slots.

FAA's Determination

We are proposing this AD because we evaluated all the relevant information and determined the definition of shop visit was too restrictive, and that the unsafe condition described previously is likely to exist or develop in other products of these same type designs.

Proposed AD Requirements

This proposed AD would change the definition of a shop visit in AD 2011-09-07 to “whenever all compressor blades are removed from the HP compressor drum.” This proposed AD would also allow using ASB No. RB.211-72-AF964, Revision 1, dated June 6, 2008, or ASB No. RB.211-72-AF964, Revision 2, dated June 8, 2011, to perform the inspection.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 371 products of U.S. registry. We also estimate that it would take about 20 work-hours per product to comply with this AD. The average labor rate is $85 per work-hour. No parts would be required per product. Based on these figures, we estimate the cost of the AD on U.S. operators to be $630,700.

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 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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

List of Subjects in 14 CFR Part 39

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

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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 removing airworthiness directive (AD) 2011-09-07, Amendment 39-166679 (76 FR 24793, May 3, 2011), and adding the following new AD:

Rolls-Royce plc: Docket No. FAA-2010-0562; Directorate Identifier 2009-NE-29-AD.

(a) Comments Due Date

The FAA must receive comments on this AD action by December 19, 2011.

(b) Affected ADs

This AD supersedes AD 2011-09-07, Amendment 39-16669 (76 FR 24793, May 3, 2011).

(c) Applicability

This AD applies to Rolls-Royce plc (RR) model RB211-524G2-T-19, -524G3-T-19, -524H-T-36, and -524H2-T-19; and RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61 556B2-61, 560-61, 560A2-61; RB211-Trent 768-60, 772-60, 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines that have a high-pressure (HP) compressor stage 1 to 4 rotor disc with a part number (P/N) listed in Table 1 of this AD.

Table 1—Affected HP Compressor Stage 1 to 4 Rotor Disc P/Ns by Engine Model

Engine model	HP compressor stage 1 to 4 rotor disc P/N
(1) RB211-524G2-T-19, -524G3-T-19, -524H-T-36, and -524H2-T-19	FW20195, FK25502, or FW23711.
(2) RB211 Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, and 560A2-61	FK30524.
(3) RB211 Trent 768-60, 772-60, and 772B-60	FK22745, FK24031, FK26185, FK23313, FK25502, FK32129, FW20195, FW20196, FW20197, FW20638, or FW23711.
(4) RB211 Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17	FK24009, FK26167, FK32580, FW11590, or FW61622.

(d) Unsafe Condition

This AD was prompted by our determination that the definition of “shop visit” in the existing AD is too restrictive, in that it would require operators to inspect more often than required to ensure safety. We are issuing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, release of uncontained engine debris, and damage to the airplane.

(e) Compliance

Comply with this AD within the compliance times specified, unless already done.

(f) Cleaning and Inspection

(1) Clean and perform a fluorescent penetrant inspection of the HP compressor stage 1 to 4 rotor discs at the first shop visit after accumulating 1,000 cycles since new on the stage 1 to 4 rotor discs or at the next shop visit after the effective date of this AD, which ever occurs later.

(2) Use paragraph 3.A through 3.E.(11) of the Accomplishment Instructions of Rolls-Royce Alert Service Bulletin (ASB) No. RB.211-72-AF964, Revision 1, dated June 6, 2008, or ASB No. RB.211-72-AF964, Revision 2, dated June 8, 2011, to do the inspections.

(3) Thereafter at every engine shop visit, perform the inspection specified by paragraph (f) of this AD.

(g) Definition

For the purpose of this AD, an “engine shop visit” is whenever all compressor blades are removed from the HP compressor drum.

(h) Alternative Methods of Compliance (AMOCs)

The Manager, Engine Certification Office, FAA may approve AMOCs for this AD. Use the procedures found in 14 CFR 39.19 to make your request.

(i) Related Information

(1) For more information about this AD, contact Alan Strom, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: [phone]; fax: [phone]; e-mail: [e-mail].

(2) See European Aviation Safety Agency Airworthiness Directive 2011-0073R1, dated April 8, 2009, for related information.

(3) For service information identified in this AD, contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone: [phone]; fax: [phone] or e-mail from http://www.rolls-royce.com/​contact/​civil_​team.jsp,, or download the publication from https://www.aeromanager.com. You may review copies at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125.

Issued in Burlington, Massachusetts, on October 14, 2011.

Peter A. White,

Manager, Engine & Propeller Directorate, Aircraft Certification Service.