Airworthiness Directives; Rolls-Royce plc RB211 Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment supersedes an existing airworthiness directive (AD) applicable to certain Rolls-Royce plc (R-R) RB211 series turbofan engines. That AD currently requires the removal from service of intermediate pressure (IP) compressor stage 6-7 rotor shafts that exceed reduced cyclic life limits. This amendment requires further reduction of cyclic life limits and introduction of new reduced cyclic bands for rework. This action is prompted by additional stress analysis conducted following failure of an IP compressor stage 6 disk. The actions specified by this AD are intended to prevent an uncontained engine failure due to rupture of an IP compressor stage 6-7 rotor shaft.

DATES:

Effective August 7, 2000. The incorporation by reference of certain publications listed in the rule is approved by the Director of the Federal Register as of August 7, 2000.

ADDRESSES:

The service information referenced in this AD may be obtained from Rolls-Royce plc, Technical Publications Department, P.O. Box 31, Derby, DE24 8BJ, UK, telephone 011-44-1332-242424. This information may be examined at the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Jason Yang, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7747, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 94-18-03, Amendment 39-9016 (59 FR 46536), applicable to R-R RB211-22B and -524 series turbofan engines, was published in the Federal Register on August 31, 1999 (64 FR 47447). That action proposed to require the removal from service of IP compressor stage 6-7 rotor shafts that exceed reduced cyclic life limits.

Conclusion

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Economic Analysis

There are approximately 1,300 engines of the affected design in the worldwide fleet. The manufacturer has advised the FAA that there are 228 engines installed on aircraft of U.S. registry that will be affected by this AD. It will take approximately 24 work hours or $1,440 per engine to accomplish the proposed rework actions, if rework of the rotor shafts is selected. Otherwise, to maintain the record of the cyclic life of IP compressor stage 6-7 rotor shafts has minimum economic impact on U.S operators. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be less than $330,000.

Regulatory Impact

This final rule does not have federalism implications, as defined in Executive Order 13132, because it does 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 final rule.

For the reasons discussed above, I certify that this action: (1) Is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

2. Section 39.13 is amended by removing amendment 39-9016 ( 59 FR 46536, September 9, 1994) and by adding a new airworthiness directive to read as follows:

2000-11-10 Rolls-Royce plc: Amendment 39-11758. Docket No. 94-ANE-16-AD. Supersedes AD 94-18-03, Amendment 39-9016.

Applicability

Rolls-Royce plc (R-R) Model RB211-22B and -524 series turbofan engines, not incorporating new intermediate pressure (IP) compressor stage 6-7 rotor shafts assemblies with redesigned stage 6 disks in accordance with R-R Service Bulletin (SB) No. RB.211-72-9993, dated August 26, 1994. These engines are installed on but not limited to Boeing 747 series and 767 series, and Lockheed L-1011 series aircraft.

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 (e) 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

Required as indicated, unless previously accomplished.

To prevent an uncontained engine failure due to rupture of an IP compressor stage 6-7 rotor shaft, accomplish the following:

Corrective Action

(a) For IP compressor stage 6-7 rotor shafts that have not been reworked in accordance with SB RB.211-72-9594, Revision 8, dated January 14, 1999, Revision 7, dated September 16, 1994, Revision 6, dated August 12, 1994, or Revision 5, dated February 12, 1993, remove the rotor shafts prior to exceeding the life limits established in Table 1 of this AD under sub-title “Pre SB72-9594” and replace with serviceable parts.

(b) Remove from service IP stage 6-7 rotor shafts that have been reworked in accordance with R-R SB RB.211-72-9594, Revision 8, dated January 14, 1999, Revision 7, dated September 16, 1994, Revision 6, dated August 12, 1994, or Revision 5, dated February 12, 1993, prior to exceeding the new, reduced cyclic life listed in Table 1 of this AD under the sub-title “Post SB72-9594” and replace with serviceable parts.

(c) Remove from service IP compressor stage 6-7 rotor shafts that have been reworked in accordance with R-R SB RB.211-72-9618, dated August 7, 1992, prior to exceeding the new, reduced cyclic life limits listed in Table 1 of this AD under the sub-title “Post SB72-9618” and replace with serviceable parts.

(d) IP compressor stage 6-7 rotor shaft rework in accordance with R-R SB RB.211-72-9594 can only be accomplished when the cyclic life of the part falls within the rework bands established in Table 1 of this AD. To accomplish rework of IP compressor stage 6-7 rotor shafts prior to reaching the lower limit of the rework bands specified in Table 1 of this AD, the part must be artificially aged to the cyclic life which defines the lower limit of the applicable rework bands in Table 1 of this AD.

Note 2:

For example, if the lower limit of the rework band is 8,000 cycles, and the part is reworked at 7,000 cycles, the part must be artificially aged by adding 1,000 cycles to the cycles since new recorded on the part; i.e., on return to service the cycles since new on this part would be 8,000 cycles.

Alternative Method of Compliance

(e) 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. Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.

Note 3:

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

Ferry Flights

(f) 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.

Incorporation By Reference

(g) The actions of this AD shall be done in accordance with the following R-R Service Bulletins:

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Rolls-Royce plc, P.O. Box 31, Derby, DE24 8BJ, UK, telephone 011-44-1332-242424. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

(h) This amendment becomes effective on August 7, 2000.