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Proposed Rule

Airworthiness Directives; Rolls-Royce RB211 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, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The Federal Aviation Administration proposes to adopt a new airworthiness directive (AD) that is applicable to Rolls-Royce (RR) plc RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 series turbofan engines. This proposal would require initial and repetitive ultrasonic inspections of low pressure compressor (LPC) fan blade roots for cracks. This proposal would also require relubrication of LPC fan blades before reinstallation. This proposal is prompted by the discovery of cracks on LPC fan blade roots during an engine overhaul. The actions specified by the proposed AD are intended to detect cracks in LPC fan blade roots, which if not detected, could lead to uncontained multiple fan blade failure, and damage to the airplane.

DATES:

Comments must be received by October 9, 2001.

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-13-AD, 12 New England Executive Park, Burlington, MA 01803-5299. 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. Comments may be inspected at this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. Information regarding this proposed AD may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

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FOR FURTHER INFORMATION CONTACT:

James Lawrence, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 238-7176; 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 2000-NE-13-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. 2000-NE-13-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 (UK), recently notified the FAA that an unsafe condition may exist on Rolls-Royce plc (RR) RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 series turbofan engines. The CAA advises that during a recent overhaul inspection of a set of LPC fan blades having high cyclic lives, small cracks in the blade roots, on the concave root flanks, were discovered. Cracking of the blade roots, if not corrected, could lead to the propagation of blade cracks, resulting in uncontained multiple fan blade failure, and damage to the airplane.

Manufacturer's Service Information

Rolls-Royce plc has issued service bulletin (SB) RB.211-72-C879, dated January 11, 2000, that specifies ultrasonic inspection of high cyclic life blades either on-wing or at shop visit. The CAA classified this service bulletin as mandatory and issued AD 002-01-2000 in order to assure the airworthiness of these Rolls-Royce plc engines in the UK.

Bilateral Airworthiness Agreement

This engine series is manufactured in the UK, and is type certificated for operation in the United States under the provisions of § 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 of an Unsafe Condition and Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other RR RB211-535E4 series turbofan engines of the same type design, that are used on Boeing 757 airplanes registered in the United States, the proposed AD would require initial and repetitive ultrasonic inspections of fan blade roots on-wing and during overhaul, and relubrication, according to accumulated life cycles.Start Printed Page 41809

Economic Impact

There are approximately 1,021 engines of the affected design in the worldwide fleet. The FAA estimates that 545 engines installed on aircraft of U.S. registry would be affected by this proposed AD. It will take approximately 7.0 work hours per engine to accomplish an on-wing initial inspection, and 2 hours per engine to accomplish an overhaul initial inspection of the proposed actions. The average labor rate is $60 per work hour. Since the actions are inspections, there are no required parts costs. Based on these figures, the FAA estimates the total cost impact for on-wing initial inspections only, of the proposed AD on U.S. operators, to be $228,900, and for overhaul initial inspections only, to be $65,400.

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. 2000-NE-13-AD.

Applicability: This airworthiness directive (AD) is applicable to Rolls-Royce (RR) plc RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 series turbofan engines with low pressure compressor (LPC) fan blades, part numbers (P/N) listed in the following Table 1 of this AD. These engines are installed on but not limited to Boeing 757 and Tupolev Tu204 series airplanes. Table 1 follows:

Table 1.—Applicable LPC Fan Blade P/N's.

UL16135UL16171UL16182UL19643UL20044
UL20132UL20616UL21345UL22286UL23122
UL24525UL24528UL24530UL24532UL24534
UL27992UL28601UL28602UL29511UL29556
UL30817UL30819UL30933UL30935UL33707
UL33709UL36992UL37090UL37272UL37274
UL37276UL37278UL38029UL38032

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 (c) 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 detect cracks in LPC fan blade roots, which if not detected, could lead to uncontained multiple fan blade failure, and damage to the airplane, do the following using:

Initial Inspection and Relubrication

(a) Ultrasonically inspect and relubricate all LPC fan blades using the cycles-since-new from one of the following appropriate Flight Profile tables, specified in paragraphs (a)(8), (a)(9), or (a)(10) this AD as follows:

(1) If not already done, remove LPC fan blades.

(2) Remove dry film lubricant from LPC fan blade roots.

(3) Calibrate ultrasonic inspection probe and flaw detector in accordance with Appendix 1, paragraphs 2.A. through 2.I. of Rolls-Royce (RR) Service Bulletin (SB) RB.211-72-C879, dated January 11, 2000.

(4) Ultrasonically inspect LPC fan blades in accordance with Appendix 1, paragraphs 3.A. through 3.D. of RR SB RB.211-72-C879, dated January 11, 2000.

(5) Replace any LPC fan blades that do not meet the acceptance criteria in Appendix 1, paragraphs 4.A. through 4.B. of RR SB RB.211-72-C879, dated January 11, 2000.

(6) Replace any missing chocking pads.

(7) Relubricate LPC fan blade roots with dry film lubricant before installing LPC fan blades.

(8) For engines that have operated only to flight profile “A,” use the following Table 2:

Table 2.—Engines Having Operated Only to Flight Profile “A” Before Inspection, as Defined in the Aircraft Maintenance Manual.

Number of cycles-since-new (CSN) on the Effective Date of This AD:Inspect and Relubricate Within:
(i) 17,000 or fewer CSN350 cycles-in-service (CIS) of accumulating 17,000 CSN.
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(ii) 17,001 to 18,000 CSN350 CIS after the effective date of this AD.
(iii) 18,001 to 20,000 CSN150 CIS after the effective date of this AD.
(iv) In excess of 20,000 CSN50 CIS after the effective date of this AD.

(9) For engines that have operated only to flight profile “B,'' use the following Table 3:

Table 3.—Engines Having Operated Only to Flight Profile “B” Before Inspection, as Defined in the Aircraft Maintenance Manual.

Number of (CSN) on the Effective Date of This AD:Inspect and Relubricate Within:
(i) 12,000 or fewer CSN350 CIS of accumulating 13,000 CSN.
(ii) 12,001 to 13,000 CSN350 CIS after the effective date of this AD.
(iii) 13,001 to 15,000 CSN150 CIS after the effective date of this AD.
(iv) In excess of 15,000 CSN50 CIS after the effective date of this AD.

(10) For engines that have operated to flight profile “A” and “B,” use the following Table 2:

Table 4.—Engines Having Operated to Both Flight Profiles “A” and “B” Before Inspection, as Defined in the Aircraft Maintenance Manual.

Final Life (FL) Calculation on the Effective Date of This AD:Inspect and Relubricate Within:
(i) Less than 65% FL350 CIS of accumulating 65% FL.
(ii) 65% FL to 65% FL plus 1,000 CIS350 CIS after the effective date of this AD.
(iii) 65% FL plus 1,000 CIS to 65% FL plus 3,000 CIS150 CIS after the effective date of this AD.
(iv) More than 65% FL plus 3,000 CIS50 CIS after the effective date of this AD.

Repetitive Inspections and Relubrication

(b) Thereafter, inspect for cracks and relubricate all LPC fan blades in accordance with paragraphs (a)(1) through (a)(7) of this AD, within 1,000 CIS of the last inspection and lubrication.

Alternative Method 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 shall 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 with §§ 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 accomplished.

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Issued in Burlington, Massachusetts, on July 12, 2001.

Mark C. Fulmer,

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

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[FR Doc. 01-19937 Filed 8-8-01; 8:45 am]

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