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Proposed Rule

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

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period.

SUMMARY:

This notice revises an earlier proposed airworthiness directive (AD), applicable to Rolls Royce plc (RR) RB211-524 series turbofan engines with certain part number (P/N) intermediate pressure (IP) compressor stage 5 disks installed. That proposal required new reduced IP compressor stage 5 disk cyclic limits. That proposal also required removing from service affected disks that already exceed the new reduced cyclic limit, and removing other affected disks before exceeding their cyclic limits, using a drawdown schedule. That proposal resulted from the discovery of cracks in the cooling air hole areas of the disk front spacer arm. This Supplemental Notice of Proposed Rulemaking (SNPRM) revises the proposed rule by correcting certain cycle life limits specified in Table 3 of that AD and by clarifying certain inspections. We are proposing this AD to prevent IP compressor stage 5 disk failure, which could result in uncontained engine failure and possible damage to the airplane.

DATES:

Comments must be received by April 4, 2005.

ADDRESSES:

Use one of the following addresses to comment 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: (781) 238-7055.
  • By e-mail: 9-ane-adcomment@faa.gov.

You can get the service information identified in this proposed AD from Rolls-Royce plc, PO Box 31 Derby, DE248BJ, United Kingdom; telephone 011-44-1332-242424; fax 011-44-1332-249936.

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:

Ian Dargin, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7178; fax (781) 238-7199.

End Further Info End Preamble Start Supplemental Information

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.

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 October 21, 2003 we issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an AD to apply to RR RB211-524 series turbofan engines, with certain P/N IP compressor stage 5 disks installed. The Office of the Federal Register published that proposal as a notice of proposed rulemaking (NPRM) in the Federal Register on October 27, 2003 (68 FR 61158). That NPRM would have required new reduced IP compressor stage 5 disk cyclic limits. The NPRM also required removing from service affected disks that already exceed the new reduced cyclic limit, and removing other affected disks before exceeding their cyclic limits, using a drawdown schedule. That NPRM resulted from the discovery of cracks in the cooling air hole areas of the disk front spacer arm. That condition, if not corrected, could result in IP compressor stage 5 disk failure, which could result in uncontained engine failure and possible damage to the airplane.

Since we issued that NPRM, we found an error in Table 3 at the date December 1, 2008 row. The cycle life limits in columns 4 and 5 of this row were written incorrectly as 12,000. We have corrected those cycle life limits to 8,900 and 9,000 CIS, respectively. We have removed the phrase “one-time” in reference to on-wing inspections. We also added a sentence to clarify that an on-wing inspection may be used to extend service life only once between shop visit inspections of the disk.

Since these changes expand the scope of the originally proposed rule, we determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Manufacturer's Service Information

We have reviewed and approved the technical contents of RR Mandatory Service Bulletin (MSB) No. RB.211-72-D428, Revision 3, dated June 30, 2003, that specifies a drawdown schedule for Start Printed Page 5391removing from service affected IP compressor stage 5 disks, using new RR Time Limits Manual (TLM), 05-10-01 cyclic limits. The MSB also describes procedures for optional inspections at each shop visit to extend the disk life beyond the lives specified. The Civil Aviation Authority (CAA), the airworthiness authority of the United Kingdom (U.K.), has classified this service bulletin as mandatory and issued AD 006-04-2002 to ensure the airworthiness of these RR turbofan engines in the U.K. We have also reviewed and approved the technical contents of Service Bulletin (SB) No. RB.211-72-E148, dated March 13, 2003 and SB No. RB.211-72-E150, Revision 1, dated June 4, 2003, that provide an optional on-wing ECI of the affected disks, to extend the disk life beyond the lives specified.

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

This proposed AD adds a requirement to change the service cyclic limits in the Time Limits Manual and to remove or inspect disks not later than 30 days after the effective date of this AD.

FAA's Determination of an Unsafe Condition and Proposed Actions

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 disk cyclic limits.
  • Removing from service affected disks that already exceed the new reduced cyclic limit.
  • Removing other affected disks before exceeding their cyclic limits, using a drawdown schedule.
  • Allowing optional inspections at each shop visit or an on-wing ECI to extend the disk life beyond the specified life.

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

Economic Analysis

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 will be affected by this proposed AD. We also estimate that it will take about 8 work hours per engine to perform an inspection, and 300 work hours per engine to replace an IP compressor stage 5 disk. The average labor rate is $65 per work hour. Required parts will cost about $49,000 per engine. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $2,415,700.

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 Analysis

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 at the address listed under ADDRESSES.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

Under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 14 CFR part 39 as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[Amended]

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

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

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by April 4, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the Rolls-Royce plc (RR) RB211-524 series turbofan engines listed in the following Table 1, with intermediate pressure (IP) compressor stage 5 disk 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. Start Printed Page 5392

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

LK60130LK65932LK69021LK81269LK83282
LK83283UL12290UL15743UL15744UL15745
UL19132UL20785UL20832UL23291UL25011
UL36821UL36977UL36978UL36979UL36980
UL36981UL36982UL36983UL37078UL37079
UL37080UL37081UL37082UL37083UL37084

Unsafe Condition

(d) This AD results from discovery of cracks in the cooling air hole areas of the disk front spacer arm. The actions specified in this AD are intended to prevent IP compressor stage 5 disk 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 contained in the Time Limits Manual, 05-10-01, 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 limitEngine 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, 200213,500 cycles-in-service (CIS)16,150 CIS16,000 CIS16,200 CIS
April 1, 200313,500 CIS13,500 CIS13,500 CIS14,000 CIS
December 1, 200312,000 CIS13,500 CIS13,500 CIS14,000 CIS
December 1, 200411,000 CIS13,500 CIS12,000 CIS12,000 CIS
December 1, 200511,000 CIS12,000 CIS12,000 CIS12,000 CIS
December 1, 20087,830 CIS8,700 CIS8,900 CIS9,000 CIS

Optional Inspections

(g) Before December 1, 2008, optional inspections are allowed at each shop visit or on-wing to extend the disk 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 disk. Information on corrosion protection removal can be found in the Engine Manual.

(2) Visual-inspect and binocular-inspect the IP stage 5 disk for corrosion pitting at the cooling air holes and defender holes in the disk 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. Information on disk corrosion pitting limits can be found in the Engine Manual.

(i) If the disk has corrosion pitting in excess of limits, remove the disk from service.

(ii) If the disk is free from corrosion pitting, MPI the entire disk. Information on MPI can be found in the Engine Manual. If the disk passes MPI and no cracks are found, complete all other inspections, re-apply corrosion protection to disk, and return the disk to service in accordance with the cyclic limits allowed by paragraph (k) 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.

(iii) If the disk has corrosion pitting within limits, ECI all disk 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. If the disk passes ECI and no cracks are found, MPI the entire disk. Information on MPI can be found in the Engine Manual. If the disk passes MPI and no cracks are found, re-apply corrosion protection to disk, and return the disk to service in accordance with the cyclic limits allowed by paragraph (k) of this AD.

Optional On-Wing EC Inspections

(i) For RB211-524B2/C2 and RB211-524B4/D4 engine models, an on-wing ECI of the IP compressor stage 5 disk may be performed only once between shop visit inspections. Follow paragraphs 3.A. through 3.F. of the Accomplishment Instructions of RR SB No. RB.211-72-E148, dated March 13, 2003, and RR SB No. RB.211-72-E150, Revision 1, dated June 4, 2003, respectively, to do the ECI. If the disk passes the ECI and no cracks are found, an extension is allowed as specified in paragraph (k) of this AD.

Definition of Shop Visit

(j) 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 a Lockheed L-1011 airplane).

Cyclic Life Extension

(k) Disks that pass an optional inspection may remain in service after that inspection for the additional cycles listed in the following Table 4, until the next inspection, or December 1, 2008, or until the cyclic life limit published in the Time Limits Manual is reached, whichever occurs first.

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, B4-02, B4-D-02
Extension After Passing MPI1,600 cycles2,000 cycles2,000 cycles2,000 cycles.
Start Printed Page 5393
Extension After Passing In-Shop ECI3,800 cycles4,500 cycles4,500 cycles4,500 cycles.
Extension After Passing On-Wing ECI1,000 cycles1,200 cycles1,200 cycles1,200 cycles.

Disks That Have Been Intermixed Between Engine Models

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

Alternative Methods of Compliance

(m) 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.

Credit for Previous Inspections

(n) Inspections done using RR SB No. RB.211-72-E150, dated April 17, 2003 are acceptable in meeting the requirements of this AD.

Reporting Requirement

(o) Report findings of all inspections of the IP stage 5 disk using paragraph 3.B.(2) of the Accomplishment Instructions of RR ASB RB.211-72-D428, Revision 3, dated June 30, 2003. The Office of Management and Budget (OMB) has approved the reporting requirements specified in Paragraph 3.B. of the Accomplishment Instructions of RR ASB RB.211-72-D428, Revision 3, dated June 30, 2003, and assigned OMB control number 2120-0056.

Related Information

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

Start Signature

Issued in Burlington, Massachusetts, on January 25, 2005.

Francis A. Favara,

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

End Signature End Part End Supplemental Information

[FR Doc. 05-1799 Filed 2-1-05; 8:45 am]

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