03-26980. Airworthiness Directives; Rolls-Royce plc RB211-524 Series Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for Rolls-Royce plc (RR) RB211-524 series turbofan engines, with certain part number (P/N) intermediate pressure (IP) compressor stage 5 discs installed. This proposed AD would establish new reduced IP compressor stage 5 disc cyclic limits. This action would also require removing from service, affected discs that already exceed the new reduced cyclic limit, and removing other affected discs before exceeding their cyclic limits, using a drawdown schedule. This action would also allow optional inspections at each shop visit or a one-time on-wing eddy current inspection (ECI) to extend the disc life beyond the lives specified. This proposed AD is prompted by the discovery of cracks in the cooling air hole areas of the disc front spacer arm. We are proposing this AD to prevent IP compressor stage 5 disc failure, which could result in uncontained engine failure and possible damage to the airplane.

DATES:

We must receive any comments on this proposed AD by December 26, 2003.

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. 2002-NE-40-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
• By fax: [phone].
• By e-mail: [e-mail].

You can get the service information identified in this proposed AD from Rolls-Royce plc, P.O. Box 31 Derby, DE248BJ, United Kingdom; telephone [phone]; fax [phone].

You may examine the AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT:

Ian Dargin, 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

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. 2002-NE-40-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.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You may get more information about plain language at http://www.faa.gov/​language and http://www.plainlanguage.gov.

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

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 certain RR model RB211-524 series turbofan engines. The CAA reports that cracks were found, during overhaul, in the cooling air hole areas of the disc front spacer arm. The engine manufacturer has performed a reassessment of the safe cyclic limits of certain IP compressor stage 5 discs. The cyclic limits of these discs are reduced based on that reassessment. This condition, if not corrected, could result in uncontained engine failure and possible damage to the airplane.

Relevant Service Information

We have reviewed and approved the technical contents of mandatory service bulletin (MSB) RB.211-72-D428, Revision 3, dated June 30, 2003, that specifies a drawdown schedule for removing from service affected IP compressor stage 5 discs, using new Time Limits Manual (TLM) cyclic limits. The MSB also describes procedures for optional inspections at each shop visit to extend the disc life beyond the lives specified. The CAA has classified this service bulletin as mandatory and issued AD 006-04-2002 in order to ensure the airworthiness of these RR plc turbofan engines in the U.K. We have also reviewed and approved the technical contents of Service Bulletin (SB) RB.211-72-E148, dated March 13, 2003 and SB RB.211-72-E150, dated April 17, 2003 that provide an optional on-wing ECI of the affected discs, to extend the disc life beyond the lives specified.

Differences Between This Proposed AD and the Manufacturer's Service Information

The compliance time is added, to remove or inspect discs not later than 30 days after the effective date of this AD.

FAA's Determination and Requirements of the Proposed AD

These engine models, manufactured in the U.K., 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. Under this bilateral airworthiness agreement, the CAA has kept us informed of the situation described above. We have examined the CAA's findings, 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. Therefore, we are proposing this AD, which would require:

• Establishing new reduced IP compressor stage 5 disc cyclic limits.
• Removing from service affected discs that already exceed the new reduced cyclic limit.
• Removing other affected discs before exceeding their cyclic limits, using a drawdown schedule.
• Allowing optional inspections at each shop visit or a one-time on-wing ECI to extend the disc life beyond the specified life.

The proposed AD would require you to use the service information described previously to perform these actions.

Changes to 14 CFR Part 39—Effect on the Proposed AD

On July 10, 2002, we published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Costs of Compliance

There are about 939 RR RB211-524 series turbofan engines of the affected design in the worldwide fleet. We estimate that 35 engines installed on airplanes of U.S. registry would be affected by this proposed AD. We also estimate that it would take about 8 work hours per engine to perform an inspection, and 300 work hours per engine to replace an IP compressor stage 5 disc. The average labor rate is $65 per work hour. Required parts would cost about $49,000 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $2,397,500.

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. 2002-NE-40-AD” in your request.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

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:

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 adding the following new airworthiness directive:

Rolls-Royce plc: Docket No. 2002-NE-40-AD.

Comments Due Date

(a) The FAA must receive comments on this airworthiness directive (AD) action by December 26, 2003.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the Rolls-Royce plc RB211-524 series turbofan engines listed in the following Table 1, with intermediate pressure (IP) compressor stage 5 disc part numbers (P/Ns) listed in Table 2 of this AD, installed.

Table 1.—Engine Models Affected

-524B-02	-524B-B-02	-524B3-02	-524B4-02	-524B4-D-02
-524B2-19	-524B2-B-19	-524C2-19	-524C2-B-19	-524D4-19
-524D4-B-19	-524D4X-19	524D4X-B-19	-524D4-39	-524D4-B-39
-524G2-19	-524G2-T-19	-524G3-19	-524G3-T-19	-524H2-19
-524H2-T-19	-524H-36	-524H-T-36

These engines are installed on, but not limited to, Boeing 747, 767, and Lockheed L-1011 airplanes.

Table 2.—IP Compressor Stage 5 Disc P/Ns Affected

LK60130	LK65932	LK69021	LK81269	LK83282
LK83283	UL12290	UL15743	UL15744	UL15745
UL19132	UL20785	UL20832	UL23291	UL25011
UL36821	UL36977	UL36978	UL36979	UL36980
UL36981	UL36982	UL36983	UL37078	UL37079
UL37080	UL37081	UL37082	UL37083	UL37084

Unsafe Condition

(d) This AD is prompted by the discovery of cracks in the cooling air hole areas of the IP compressor stage 5 disc front spacer arm. We are issuing this AD to prevent IP compressor stage 5 disc failure, which could result in uncontained engine failure and possible damage to the airplane.

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.

Cycle Limits

(f) Change the service cyclic limits for the IP compressor stage 5 discs installed in the engine models listed in the following Table 3, within 30 days after the effective date of this AD.

Table 3.—Cyclic Life Limits Without Qualifying Magnetic Particle Inspection (MPI) or Eddy Current Inspection (ECI)

Date of reduced life limit	Engine models
	-524G2, G2-T, G3, G3-T, H2, H2-T, H-36,H-T-36	-524D4, D4-B, D4-B-39, D4X, D4X-B, D4-39	-524B2, B2-B, C2, C2-B	-524B-02, B-B-02, B3-02, B4-02, B4-D-02
November 30, 2002	1 13,500 CIS	16,150 CIS	16,000 CIS	16,200 CIS
April 1, 2003	13,500 CIS	13,500 CIS	13,500 CIS	14,000 CIS
December 1, 2003	12,000 CIS	13,500 CIS	13,500 CIS	14,000 CIS
December 1, 2004	11,000 CIS	13,500 CIS	12,000 CIS	12,000 CIS
December 1, 2005	11,000 CIS	12,000 CIS	12,000 CIS	12,000 CIS
December 1, 2008	7,830 CIS	8,700 CIS	12,000 CIS	12,000 CIS
1 Cycles-in-service.

Optional Inspections

(g) Before December 1, 2008, optional inspections are allowed at each shop visit or a one-time on-wing ECI is allowed to extend the disc life. Guidance for these inspections is provided in paragraphs (h) or (i) of this AD.

Optional Inspections at Shop Visit

(h) Perform optional inspections at shop visit, as follows:

(1) Remove corrosion protection from IP stage 5 disc. Information on corrosion protection removal can be found in the Engine Manual.

(2) Visual-inspect and binocular-inspect the IP stage 5 disc for corrosion pitting at the cooling air holes and defender holes in the disc front spacer arm. Follow paragraph 3.C. of the Accomplishment Instructions of RR MSB No. RB.211-72-D428, Revision 3, dated June 30, 2003.

(3) Discs with corrosion pitting in excess of limits must be removed from service. Information on disc corrosion pitting limits can be found in the Engine Manual.

(4) If the disc is free from corrosion pitting, MPI entire disc. Inspection on MPI can be found in the Engine Manual.

(5) If the disc has corrosion pitting within limits, ECI all disc cooling air holes, defender holes, and inner and outer faces. Follow paragraph 3.D. of the Accomplishment Instructions of RR MSB No. RB.211-72-D428, Revision 3, dated June 30, 2003. Information on corrosion pitting limits can be found in the Engine Manual.

(6) If the disc passes ECI and no cracks are found, MPI entire disc. Information on MPI can be found in the Engine Manual.

(7) If the disc passes MPI and no cracks are found, re-apply corrosion protection to disc, and return the disc to service in accordance with the cyclic limits allowed by paragraph (l) of this AD. Information on MPI limits can be found in the Engine Manual. Information on re-applying corrosion protection can be found in RR Repair FRS5900.

Optional One-Time On-Wing EC Inspection

(i) For RB211-524B2/C2 and RB211-524B4/D4 engine models, a one-time on-wing ECI of the IP compressor stage 5 disc may be performed in lieu of a shop visit inspection. Follow RR paragraph 3.A. through 3.F. of Accomplishment Instructions of SB No. RB.211-72-E148, and RR SB No. RB.211-72-E150, respectively, to do the ECI. If the disc passes the ECI and no cracks are found, an extension is allowed as specified in paragraph (l) of this AD.

Definition of Shop Visit

(k) For the purposes of this AD, a shop visit is defined as the separation of an engine major case flange. This definition excludes shop visits when only field maintenance type activities are performed in lieu of performing them on-wing. (i.e., for purposes such as to perform an on-wing inspection of a tail engine installation on an L1011 airplane).

Cyclic Life Extension

(l) Discs that pass an optional inspection may remain in service after that inspection for the additional cycles listed in the following Table 4, or until the next inspection, or until the December 1, 2008 life limit in Table 3 is reached, whichever occurs first.

Note 1:

Discs may remain in service for additional periods if repeat optional inspections are conducted and associated AD criteria are met.

Table 4.—Cyclic Life Extension

	Engine models
	-524G2, G2-T, G3, G3-T, H2, H2-T, H-36, H-T-36	-524D4, D4-B, D4-B-39, D4X, D4X-B, D4-39	-524B2, B2-B, C2, C2-B	-524B-02, B-B-02, B3-02, B4-0-2, B4-D-02
Extension after passing MPI	1,600 cycles	2,000 cycles	2,000 cycles	2,000 cycles.
Extension after passing In-Shop ECI	3,800 cycles	4,500 cycles	4,500 cycles	4,500 cycles.
Extension after passing On-Wing ECI	1,000 cycles	1,200 cycles	1,200 cycles	1,200 cycles.

Discs That Have Been Intermixed Between Engine Models

(m) Information on intermixing discs between engine models can be found in the RR Time Limits Manual, 05-00-01.

Alternative Methods of Compliance

(n) 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.

Material Incorporated by Reference

(o) You must use the service information specified in the following Table 5 to perform the inspections and drawdown required by this AD. Approval of incorporation by reference from the Office of the Federal Register is pending.

Table 5.—Incorporation by Reference

Service bulletin No.	Page	Revision	Date
Mandatory Service Bulletin No. RB.211-72-D428	All	3	June 30, 2003.
Total Pages: 27
Service Bulletin No. RB.211-72-E148	All	Original	March 13, 2003.
Total Pages: 83
Service Bulletin No. RB.211-72-E150	All	1	June 4, 2003.
Total pages: 72

Related Information

(p) CAA airworthiness directive 006-04-2002, dated April 2002, also addresses the subject of this AD.

Issued in Burlington, Massachusetts, on October 21, 2003.

Robert J. Ganley,

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