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Proposed Rule

Airworthiness Directives; Rolls-Royce plc RB211 Trent 875, 877, 884, 884B, 892, 892B, and 895 Series Turbofan Engines

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Information about this document as published in the Federal Register.

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AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) for Rolls-Royce plc (RR) RB211 Trent 875, 877, 884, 892, 892B, and 895 series turbofan engines. That AD currently requires repetitive application of dry film lubricant (DFL) to low pressure compressor (LPC) fan blade roots. This proposed AD would require the same actions but at more frequent intervals than the existing AD, add the Trent 884B engine to the list of engine models affected, add a fan blade part number (P/N) to the affected list of fan blades, and would relax the initial DFL repetitive application compliance time for certain fan blades that have never been removed from the disk. This proposed AD results from discovering DFL in worse condition than anticipated on fan blades fitted to disks previously run for a significant period. This proposed AD also results from the need to update the list of engine models affected, and to update the list of fan blade part numbers affected. We are proposing this AD to prevent LPC fan blade loss, which could result in an uncontained engine failure and possible aircraft damage.

DATES:

We must receive any comments on this proposed AD by April 19, 2005.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:

  • By mail: Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2001-NE-12-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
  • By fax: (781) 238-7055.
  • By e-mail: 9-ane-adcomment@faa.gov.

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.

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SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2001-NE-12—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.

Discussion

On May 16, 2002, the FAA issued AD 2002-10-15, Amendment 39-12761 (67 FR 36803, May 28, 2002). That AD requires repetitive application of DFL to LPC fan blade roots. That AD resulted from an aborted take-off resulting from LPC fan blade loss, and reports of four cracked LPC fan blade roots.

Actions Since AD 2002-10-15 was Issued

Since that AD was issued, we have determined from a sampling of DFL coatings on fan blades, that the DFL coating condition has some variation. The condition appears worse than anticipated on fan blades fitted to disks previously run for a significant period. Also, since that AD was issued, we discovered that the Trent 884B engine needs to be added to the applicability list, and fan blade, P/N FW23552, needs to be added to the list of affected blades.

Special Flight Permits Paragraph Removed

Paragraph (d) of the current AD, AD 2002-10-15, 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.

Replacement of References to Manual Tasks, Repair Schemes, and Coatings

In this proposed AD, we have replaced references in AD 2002-10-15 to Aircraft Maintenance Manual task 72-31-11-300-801-R00 (Repair Scheme FRS A031 by air spray method only), Engine Manual task 72-31-11-R001 (Repair Scheme FRS A028), and lubricants, Dow Corning 321R (Rolls-Royce (RR) Omat item 4/51), Rocol Dry Moly Spray (RR Omat item 4/52), Molydag 709 (RR Omat item 444), or PL.237/R1 (RR Omat item 4/43), with a reference to RR Alert Service Bulletin No. RB.211-72-AD347, Revision 6, dated April 22, 2004, which contains that information. Start Printed Page 8304

Bilateral Agreement Information

These engine models are manufactured in the U.K. 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. Pursuant to this bilateral airworthiness agreement, the 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 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 repetitive application of DFL to LPC fan blade roots at more frequent intervals than the existing AD;
  • Add the Trent 884B engine to the applicability;
  • Add a fan blade P/N to the affected list of fan blades; and
  • Relax the initial DFL repetitive application compliance time for certain fan blades that have never been removed from the disk.

Costs of Compliance

There are approximately 388 RR RB211 Trent 875, 877, 884, 884B, 892, 892B, and 895 series turbofan engines of the affected design in the worldwide fleet. We estimate that 106 engines installed on airplanes of U.S. registry would be affected by this proposed AD. We also estimate that it would take approximately six work hours per engine to perform the DFL application, 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 perform one repetitive application of DFL to the affected engines to be $41,340.

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); 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. 2001-NE-12-AD” in your request.

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List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

2. The FAA amends § 39.13 by removing Amendment 39-12761 (67 FR 36803, May 28, 2002) and by adding a new airworthiness directive, to read as follows:

Rolls-Royce plc: Docket No. 2001-NE-12-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by April 19, 2005.

Affected ADs

(b) This AD supersedes AD 2002-10-15, Amendment 39-12761.

Applicability

(c) This AD applies to Rolls-Royce plc (RR) RB211 Trent 875, 877, 884, 884B, 892, 892B, and 895 series turbofan engines with low pressure compressor (LPC) fan blade part numbers (P/Ns): FK 30838, FK30840, FK30842, FW12960, FW12961, FW12962, FW13175, FW18548, or FW23552. These engines are installed on, but not limited to, Boeing 777 series airplanes.

Unsafe Condition

(d) This AD results from the discovery of dry film lubricant (DFL) condition appearing worse than anticipated on fan blades fitted to disks previously run for a significant period. This AD also results from the need to update the list of engine models affected, and to update the list of fan blade part numbers affected. The actions specified in this AD are intended to prevent LPC fan blade loss, which could result in an uncontained engine failure and possible aircraft damage.

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.

(f) Apply an approved DFL to LPC fan blade roots as follows:

(1) For LPC fan blades P/Ns FW13175, FW12960, FW12961, FW12962, FW18548, and FW23552 that have never been removed from the disk, apply DFL at the first removal from the disk or before 1,200 cycles-in-service (CIS), whichever occurs first.

(2) For LPC fan blades P/Ns FW13175, FW12960, FW12961, FW12962, FW18548, and FW23552 that have been removed from the disk since entering service, apply DFL before accumulating 600 cycles-since-new (CSN) or before accumulating 600 cycles-since-last DFL application, or within 200 CIS from the effective date of this AD, whichever occurs later.

(3) For LPC fan blades P/Ns FK30842, FK30840, and FK300838, apply DFL before accumulating 600 CSN or before accumulating 600 cycles-since-last DFL application, or within 100 CIS after July 2, 2002 (effective date of superseded AD 2002-10-15), whichever occurs first.

(4) Thereafter, reapply DFL to LPC fan blade roots within 600 cycles-since-last DFL application.

(5) Information on applying DFL to fan blade roots can be found in RR Alert Service Bulletin No. RB.211-72-AD347, Revision 6, dated April 22, 2004.

Alternative Methods of Compliance

(g) 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. Start Printed Page 8305

Related Information

(h) Civil Aviation Authority Airworthiness Directive G-2004-0008, dated April 29, 2004, also addresses the subject of this AD.

Start Signature

Issued in Burlington, Massachusetts, on February 10, 2005.

Francis A. Favara,

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

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[FR Doc. 05-3191 Filed 2-17-05; 8:45 am]

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