Airworthiness directives: Royce Corp.,

[Federal Register: November 8, 2001 (Volume 66, Number 217)]

[Proposed Rules]

[Page 56493-56495]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr08no01-16]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-31-AD]

RIN 2120-AA64

Airworthiness Directives; Rolls-Royce Corporation (Formerly Allison Engine Company) 250-C28 Series 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 certain Rolls- Royce Corporation (formerly Allison Engine Company) 250-C28 series engines. This proposal would require removal of third stage turbine wheels, part number (P/N) 6899383, with certain serial numbers (SN's), from service before exceeding new, reduced life limits. This proposal would also establish a drawdown program to require the removal of those turbine wheels that exceed the new lower limit. This proposal is prompted by five reports of uncommanded shutdown caused by third stage turbine blade tip fractures, and turbine shroud fractures. The actions specified by the proposed AD are intended to prevent uncommanded shutdown of the engine due to fractures of third stage turbine blade tips and third stage turbine shrouds.

DATES: Comments must be received by January 7, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

[[Page 56494]]

Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No.2001-NE-31-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8 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: ``9-ane-adcomment@faa.gov''. Comments sent via the Internet must contain the docket number in the subject line.

FOR FURTHER INFORMATION CONTACT: John Tallarovic, Aerospace Engineer, Chicago Aircraft Certification Office, FAA, Small Airplane Directorate, 2300 East Devon Avenue, Des Plaines, IL 60018; telephone (847) 294- 8180; fax (847) 294-7834.

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 filedin 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 2001-NE-31-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. 2001-NE-31-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The FAA has received reports of five uncommanded shutdowns on Rolls-Royce Corporation 250-C28 series engines, caused by third stage turbine blade tip and turbine shroud fractures. The manufacturer's analysis indicates that this condition is caused by certain third stage turbine wheels, part number (P/N) 6899383, that have a critical dimension outside the manufacturing limit. There are believed to be 84 third stage turbine wheels with this condition. For these 84 turbine wheels, the manufacturer has reduced the life limits of 4,550 hours time-since-new (TSN) and 6,000 cycles-since-new (CSN), to life limits of 1,500 hours TSN and 3,000 CSN. This condition, if not corrected, could result in an uncommanded shutdown of the engine due to fractures of third stage turbine blade tips and third stage turbine shrouds.

Proposed Requirements of This AD

Since an unsafe condition has been identified that is likely to exist or develop on other Rolls-Royce Corporation 250-C28 series engines of the same type design, the proposed AD would require removal from service certain SN's of third stage turbine wheels before exceeding new, reduced life limits.

Economic Analysis

There are approximately 84 engines of the affected design in the worldwide fleet. The FAA estimates that 42 engines installed on helicopters of U.S. registry would be affected by this proposed AD. The FAA also estimates that it would take approximately 44 work hours per engine to accomplish the proposed actions, and that the average labor rate is $60 per work hour. The cost of a new third stage turbine wheel is approximately $4,371. Although the FAA estimates that approximately $2,929 per wheel has been lost due to life reduction, the manufacturer has stated it may reduce the new wheel cost to the customer. Based on these figures, the total cost effect of the proposed AD on U.S. operators is estimated to be $294,462.

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.

   Sec. 39.13 [Amended]

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

   Rolls-Royce Corporation: Docket No. 2001-NE-31-AD.

   Applicability

   This airworthiness directive (AD) is applicable to Rolls-Royce Corporation (formerly Allison Engine Company) 250-C28, -C28B, and - C28C model engines with third stage turbine wheels part number (P/N) 6899383, listed by serial number (SN) in the following Table 1:

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   Table 1.--SN's of Affected Third Stage Turbine Wheels

   HX91428R

   HX91489R

   HX91707R HX91456R

   HX91490R

   HX91708R HX91457R

   HX91492R

   HX91709R HX91458R

   HX91493R

   HX91710R HX91459R

   HX91494R

   HX91711R HX91461R

   HX91500R

   HX91712R HX91462R

   HX91501R

   HX91713R HX91464R

   HX91503R

   HX91714R HX914659

   HX91504R

   HX91715R HX91465R

   HX91506R

   HX91721R HX91466R

   HX91507R

   HX91722R HX91467R

   HX91508R

   HX91726R HX91468R

   HX91510R

   HX91733R HX91469R

   HX91511R

   HX91735R HX91471R

   HX91512R

   HX91736R HX91472R

   HX91513R

   HX91738R HX91473R

   HX91519R

   HX91742R HX91474R

   HX91520R

   HX91744R HX91475R

   HX91522R

   HX91748R HX91477R

   HX91523R

   HX91749R HX91478R

   HX91524R

   HX91750R HX91480R

   HX91525R

   HX91754R HX91482R

   HX91526R

   HX91764R HX91483R

   HX91527R

   HX91765R HX91485R

   HX91528R

   HX91766R HX91486R

   HX91529R

   HX91767R HX91487R

   HX91530R

   HX91768R HX91488R

   HX91706R

   HX91769R

   These engines are installed on, but not limited to Bell Helicopter Textron 206L-1 helicopters.

   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 prevent an uncommanded shutdown of the engine due to fractures of third stage turbine blade tips and third stage turbine shrouds, do the following:

   (a) Remove from service the third stage turbine wheels, P/N 6899383, listed by SN in Table 1 of this AD, in accordance with the following Table 2:

   Table 2.--Removal Schedule

   For third stage by turbine wheels on the effective date of this AD

   Remove by

   (1) With fewer than 3,000 cycles-since- 3,000 CSN or 1,500 hours TSN, new (CSN), and fewer than 1,500 hours whichever occurs earlier. time-since-new (TSN). (2) With between 3,000 and 6,000 CSN, 200 additional cycles, after and fewer than 1,500 hours TSN.

   the effective date of this AD. (3) With fewer than 3,000 CSN, and 100 additional hours, after the between 1,500 and 3,000 hours TSN. effective date of this AD. (4) With between 3,000 and 6,000 CSN 200 additionally cycles or 100 and between 1,500 and 3,000 hours TSN. additional hours, after the effective date of this AD, whichever occurs earlier. (5) With more than 6,000 CSN, or more Before further flight. than 3,000 hours TSN.

   (b) After the effective date of this AD, do not install any third stage turbine wheels listed by SN in Table 1 of this AD. Thereafter, except as provided in paragraph (c) of this AD, no alternative cyclic life limits may be approved for the turbine wheels listed inTable 1 of this AD.

   Alternative Methods 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, Chicago Aircraft Certification Office (ACO). Operators must submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Chicago ACO.

   Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Chicago ACO.

   Special Flight Permits

   (d) Special flight permits may be issued in accordance Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be done.

   Issued in Burlington, Massachusetts, on November 1, 2001. Diane S. Romanosky, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 01-28025Filed11-7-01; 8:45 am]

   BILLING CODE 4910-13-U