02-30350. Airworthiness Directives; Rolls-Royce plc Model RB211-22B Turbofan Engines

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 (RR) model RB211-22B turbofan engines with intermediate pressure (IP) compressor stage 6 to 7 rotor shaft assembly part number (P/N) UL37094 installed. This proposal would require removal from service of IP compressor stage 6 to 7 rotor shaft assemblies P/N UL37094 before reaching newly reduced life limits. This proposal is prompted by the discovery of corrosion during inspection and analysis of IP compressor stage 6 to 7 rotor shaft assemblies returned from the field. The actions specified by the proposed AD are intended to prevent corrosion-induced cracking of the IP compressor stage 6 to 7 rotor shaft assembly, resulting in an uncontained engine failure and damage to the airplane.

DATES:

Comments must be received by January 31, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2002-NE-10-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8:00 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: “[e-mail]”. Comments sent via the Internet must contain the docket number in the subject line.

Information regarding this action may be examined, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

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 [phone]; fax [phone].

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 2002-NE-10—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. 2002-NE-10-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The manufacturer has recently analyzed the conditions of some IP compressor stage 6 to 7 rotor shaft assemblies, P/N 37094, that were returned from the field, and has determined that rotor shafts of this part number are unable to achieve currently published life limits. This is due to the potential for corrosion-induced cracking to occur at these published life limits. As a result of this analysis, new lower life limits have been assigned to this P/N IP compressor stage 6 to 7 rotor shaft assembly. This condition, if not corrected, could result in corrosion-induced cracking of the IP compressor stage 6 to 7 rotor shaft assembly, resulting in an uncontained engine failure and damage to the airplane.

Proposed Requirements of this AD

Since an unsafe condition has been identified that is likely to exist or develop on other RR model RB211-22B turbofan engines of the same type design that are used on airplanes registered in the United States, the proposed AD would require removing from service IP compressor stage 6 to 7 rotor shaft assemblies, P/N UL37094, before reaching new reduced life limits. The life limits are established based on whether or not the engine has incorporated service bulletin (SB) RR SB 72-8700. That SB increases the engine thrust rating.

Economic Analysis

The FAA estimates that one engine installed on aircraft of U.S. registry would be affected by this proposed AD. The FAA also estimates that no additional labor cost will be incurred to remove the affected part, which will be at time of engine shop visit. Required parts would cost approximately $33,150 per engine, based on a part life reduction estimate. Based on these figures, the total cost of the proposed AD to U.S. operators is estimated to be $33,150.

Regulatory Analysis

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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

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:

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. Section 39.13 is amended by adding the following new airworthiness directive:

Rolls-Royce plc: Docket No. 2002-NE-10-AD.

Applicability: This airworthiness directive (AD) is applicable to Rolls-Royce (RR) model RB211-22B turbofan engines with intermediate pressure (IP) compressor stage 6 to 7 rotor shaft assembly part number (P/N) UL37094 installed. These engines are installed on, but not limited to Lockheed Martin L1011 airplanes.

Note 1:

This airworthiness directive (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 corrosion-induced cracking of the IP compressor stage 6 to 7 rotor shaft assembly, resulting in an uncontained engine failure and damage to the airplane, do the following:

(a) For engines that have not incorporated RR service bulletin (SB) 72-8700, remove IP compressor stage 6 to 7 rotor shaft assemblies from service before accumulating 13,500 cycles-since-new (CSN).

(b) For engines that have incorporated RR service bulletin (SB) 72-8700, remove IP compressor stage 6 to 7 rotor shaft assemblies from service before accumulating 12,980 cycles-since-new (CSN).

(c) After the effective date of this AD, do not install any IP compressor stage 6 to 7 rotor shaft assembly, P/N UL37094, that has accumulated the CSN specified in paragraph (a) or (b) of this AD.

Alternative Methods of Compliance

(d) 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

(e) 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 airplane to a location where the requirements of this AD can be done.

Issued in Burlington, Massachusetts, on November 20, 2002.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.