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Proposed Rule

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

Document Details

Information about this document as published in the Federal Register.

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AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to Rolls-Royce plc RB211 Trent 875, 877, 884, 892, 892B, and 895 series turbofan engines. This proposal would require reapplication of dry film lubricant to low pressure compressor (LPC) fan blade roots. This proposal is prompted by an aborted take-off resulting from LPC fan blade loss. Since this event, four additional cracked LPC fan blade roots have been reported. The actions specified by the proposed AD are intended to prevent LPC fan blade loss, which could result in an uncontained engine failure and possible aircraft damage.

DATES:

Comments must be received by February 4, 2002.

ADDRESSES:

Submit comments in triplicate to the 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. Comments may be inspected at this location between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. Comments may also be sent via the Internet using the following address: 9-ane-adcomment@faa.gov. Comments sent via the Internet must contain the docket number in the subject line. The service information referenced in the proposed rule may be obtained from Rolls-Royce plc, PO Box 31, Derby, England, DE248BJ; telephone: 011-44-1332-242-424; fax: 011-44-1332-245-418. This information may be examined, Start Printed Page 63342by 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:

Keith Mead, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 238-7744, fax: (781) 238-7199.

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SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NE-12-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRM's

Any person may obtain a copy of this NPRM by submitting a request to the 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.

Discussion

The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom (U.K.), recently notified the FAA that an unsafe condition may exist on Rolls-Royce plc RB211 Trent 875, 877, 884, 892, 892B, and 895 series turbofan engines. The CAA advises that a Trent 800 series powered aircraft experienced an aborted take-off as a result of an inability to achieve the commanded exhaust pressure ratio (EPR) on the Number 1 engine. Ground inspection of the engine revealed loss of one LPC fan blade. Since this event, four additional LPC fan blade roots have been reported cracked. Loss of the LPC fan blade resulted from high stresses and subsequent cracking in the fan blade root. Investigation by the engine manufacturer has shown that regular reapplication of dry film lubricant on the LPC fan blade root results in reduced blade to disk friction during engine operation and hence reduced blade root stressing. The FAA concurs with the manufacturer's determination as to the optimum times to perform the reapplication of the dry film lubricant, as provided in this proposal. The actions specified by the proposed AD are intended to prevent LPC fan blade loss, which could result in an uncontained engine failure and possible aircraft damage.

Manufacturer's Service Information

Rolls-Royce has issued Mandatory Service Bulletin (MSB) RB.211-72-D347, Revision 2, dated May 30, 2001, that requires initial and reapplication of dry film lubricant to LPC fan blade roots. The CAA classified this service bulletin as mandatory and issued AD 001-03-2001 in order to ensure the airworthiness of these Rolls-Royce 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. 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.

Proposed Requirements of This AD

Since an unsafe condition has been identified that is likely to exist or develop on other Rolls-Royce plc RB211 Trent 875, 877, 884, 892, 892B, and 895 series turbofan engines of the same type design , the proposed AD would require initial and reapplication of dry film lubricant to LPC blade roots. The actions would be required to be accomplished in accordance with the SB described previously.

Economic Impact

The FAA estimates that 88 engines installed on aircraft of U.S. registry would be affected by this proposed AD. The FAA also estimates that it would take approximately 6 work hours per engine to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the total labor cost impact of the proposed AD on U.S. operators is estimated to be $31,680 to accomplish each application of lubricant. The FAA estimates that operators will apply lubricant an average of 1.5 times per year, making the total annual cost of compliance with this proposal $ 47,520.

Regulatory Impact

This proposed rule does not have federalism implications, as defined in Executive Order 13132, because it 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. Accordingly, the FAA has not consulted with state authorities prior to publication of this proposed rule.

For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

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List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

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

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

Note 1:

This AD applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Compliance with this AD is required as indicated, unless already done.

To prevent LPC fan blade loss, which could result in an uncontained engine failure and possible aircraft damage, accomplish the following:

Table 1.—Initial and Repetitive Application Thresholds

LPT Fan blade part Nos.Initial compliance criteriaRepetitive compliance criteria
FK30842, FK30840, and FK30838Before achieving 600 cycles since installationRepeat at intervals not exceeding 600 cycles since last compliance.
FW12961, FW12960, FW12962, FW13175, FW18548Before achieving 1200 cycles since installationRepeat at intervals not exceeding 1200 cycles since last compliance.

(a) Apply an approved dry film lubricant to low pressure compressor (LPC) fan blade roots as specified in Table 1 above. Aircraft Maintenance Manual (AMM) task 72-31-11-300-801-R00 (Repair Scheme FRS A031 by air spray method only) or engine manual 72-31-11-R001 (Repair Scheme FRS A028) contain procedures for renewing the dry film lubricant on the blade roots. For purposes of this AD, approved lubricants are Dow Corning 321R (Rolls-Royce (RR) Omat item 4/52), Rocol Dry Moly Spray (RR Omat item 4/52), Molydag 709 (RR Omat item 444), or PL.237/R1 (RR Omat item 4/43).

Fan Blades Exceeding Initial Application Thresholds

(b) For blades that have, on the effective date of the AD, more cycles since installation than the initial compliance criteria in Table 1 of this AD, inspect blades within 100 cycles in service after the effective date of this AD.

Alternative Methods of Compliance

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office (ECO). Operators must submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

Special Flight Permits

(d) Special flight permits may be issued in accordance §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be done.

Note 3:

The subject of this AD is addressed in Civil Aviation Authority Airworthiness Directive 001-03-2001, dated March 2, 2001.

Start Signature

Issued in Burlington, Massachusetts, on November 30, 2001.

Francis A. Favara,

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

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[FR Doc. 01-30266 Filed 12-5-01; 8:45 am]

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