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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. FAA-2004-19648; Directorate Identifier 2004-NE-31-AD] 
          - RIN 2120-AA64 

# 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 Corporation (RRC) (formerly Allison Engine Company) 250-B17B, -B17C, -B17D, -B17E, -C20, -C20B, -C20F, -C20J, -C20S, and -C20W turboprop and turboshaft engines that do not have turbine energy absorbing ring, part number (P/N) 23035175, installed. This proposed AD would require installation of a turbine energy absorbing ring in the plane of the 1st stage turbine wheel. This proposed AD may also require installation of 1st stage turbine nozzles, 2nd stage turbine nozzles, and a gas producer support assembly, all modified to allow for installation of the turbine energy absorbing ring. This proposed AD results from an unacceptable rate of uncontained 1st stage turbine wheel failures. We are proposing this AD to minimize the risk of uncontained 1st stage turbine wheel fragments from causing damage to the aircraft or damage to the second engine on twin-engine installations which could lead to loss of control and loss of the aircraft. 

# DATES:

We must receive any comments on this proposed AD by January 21, 2005. 

# ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD. 
      - DOT Docket Web site: Go to http://dms.dot.gov                          and follow the instructions for sending your comments electronically.                     
      - Government-wide rulemaking Web site: Go to http://www.regulations.gov                          and follow the instructions for sending your comments electronically.                     
      - Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-001.
      - Fax: (202) 493-2251.
      - Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

You can get the service information identified in this proposed AD from Rolls-Royce Corporation, P.O. Box 420, Indianapolis, IN 46206-0420; telephone (317) 230-6400; fax (317) 230-4243. 

                        You may examine the comments on this proposed AD in the AD docket on the Internet at                         *http://dms.dot.gov*.                     

# FOR FURTHER INFORMATION CONTACT:

Melissa T. Bradley, Aerospace Engineer, Chicago Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, IL 60018-4696; telephone (847) 294-8110; fax (847) 294-7834. 

# SUPPLEMENTARY INFORMATION:

## Docket Management System (DMS) 

We have implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, we post new AD actions on the DMS and assign a DMS docket number. We track each action and assign a corresponding Directorate identifier. The DMS docket No. is in the form “Docket No. FAA-200X-XXXXX.” Each DMS docket also lists the Directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes. 

## 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 “Docket No. FAA-2004-19648; Directorate Identifier 2004-NE-31-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.                 

                    We will post all comments we receive, without change, to                     *http://dms.dot.gov,*                     including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of the DMS Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the                     **Federal Register**                     published on April 11, 2000 (65 FR 19477-78), or you may visit                     *http://dms.dot.gov.*

## Examining the AD Docket 

                    You may examine the docket that contains the proposal, any comments received and, any final disposition in person at the DMS Docket Offices between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in                     **ADDRESSES.**                     Comments will be available in the AD docket shortly after the DMS receives them.                 

## Discussion 

RRC conducted an analysis of uncontained 1st stage turbine wheel failures and the effects on aircraft. The 1st stage turbine wheel can fail as a result of in-service damage or gas producer tiebolt failure. The in-service damage is caused primarily by thermal fatigue to the turbine wheels during hot starts but has also been linked to improper alignment of the combustion liner and oil fires. 

                    The manufacturer developed a turbine energy absorbing ring to render turbine wheel fragments non-hazardous. We have determined the present rate of hazardous 1st stage turbine wheel                           ( print page 67868)                        failures is unacceptable. This condition, if not corrected, could result in hazardous uncontained 1st stage turbine wheel fragments causing damage to the airframe and the second engine on twin-engine installations which could lead to loss of control and loss of the aircraft.                 

## Relevant Service Information 

We have reviewed and approved the technical contents of RRC Alert Commercial Engine Bulletin No. CEB-A-1255, Revision 4, dated September 29, 2004, that describes procedures for installing a turbine energy absorbing ring in the plane of the 1st stage turbine wheel. We have also reviewed and approved the technical contents of RRC Alert Commercial Engine Bulletin No. CEB-A-1254, Revision 3, dated May 21, 2004, that describes procedures for modifying and installing a certain P/N gas producer support assembly. We have also reviewed and approved the technical contents of RRC Alert Commercial Engine Bulletin No. CEB-A-1253, Revision 4, dated May 21, 2004, that describes procedures for modifying and installing a certain P/N 1st stage turbine nozzle, and certain P/N 2nd stage turbine nozzle. The actions required by RRC Alert Commercial Engine Bulletin No. CEB-A-1254 and No. CEB-A-1253, if necessary, must be done before or simultaneously with the actions of Alert Commercial Engine Bulletin No. CEB-A-1255. 

## FAA's Determination and Requirements of the Proposed AD 

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. We are proposing this AD, which would require installation of a turbine energy absorbing ring. The proposed AD would require that these actions be done using Alert Commercial Engine Bulletin No. CEB-A-1255. 

## Costs of Compliance 

There are about 13,299 RRC 250-B17B, -B17C, -B17D, -B17E, -C20, -C20B, -C20F, -C20J, -C20S, and -C20W turboprop and turboshaft engines of the affected design in the worldwide fleet. We estimate that 5,000 engines installed on helicopters of U.S. registry require the installation of a turbine energy absorbing ring. Of those 5,000 engines, we also estimate that 4,000 engines require installation of a gas producer support assembly, 1st stage turbine nozzle, and 2nd stage turbine nozzle. It takes about 16 work hours per engine to install the turbine energy absorbing ring, 35 work hours to install the gas producer support assembly, and 20 work hours to install the 1st stage turbine nozzle, and 2nd stage turbine nozzle. The average labor rate is $65 per work hour. Required turbine energy absorbing rings cost about $10,765 per engine. Required gas producer support assemblies cost about $2,500 per engine. Required 1st stage turbine nozzles and 2nd stage turbine nozzles cost about $1,000 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $87,325,000. 

## 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 at the address listed under                     **ADDRESSES**                    .                 

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Safety

## 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: 

# 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 

2. The FAA amends § 39.13 by adding the following new airworthiness directive: 

**Rolls-Royce Corporation (formerly Allison Engine Company):**                                 Docket No. FAA-2004-19648; Directorate Identifier 2004-NE-31-AD.                             

## Comments Due Date 

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by January 21, 2005. 

## Affected ADs 

(b) None. 

## Applicability 

(c) This AD applies to Rolls-Royce Corporation (RRC) (formerly Allison Engine Company) 250-B17B, -B17C, -B17D, -B17E, -C20, -C20B, -C20F, -C20J, -C20S, and -C20W turboprop and turboshaft engines that do not have turbine energy absorbing ring, part number 23035175, installed. These engines are installed on, but not limited to, the following aircraft: 

Agusta A109 

Agusta A109A 

Agusta A109A II 

B-N Group BN-2T 

Bell 206A 

Bell 206B 

Bell 206L 

Eurocopter Deutchland BO-105C 

Eurocopter Deutchland BO-105S 

Eurocopter France AS355E 

Eurocopter France AS355F 

Eurocopter France AS355F1 

Eurocopter France AS355F2 

FH-1100 Manufacturing Corp FH-1100 

MDHI 369D 

MDHI 369E 

MDHI 369HM 

MDHI 369HS 

MDHI 369HE 

SIAI Marchetti s.r.l. SF600 

## Unsafe Condition

(d) This AD results from an unacceptable rate of uncontained 1st stage turbine wheel failures. We are issuing this AD to minimize the risk of uncontained 1st stage turbine wheel fragments from causing damage to the aircraft or damage to the second engine on twin-engine installations which could lead to loss of control and loss of the aircraft.

## Compliance

(e) You are responsible for having the actions required by this AD performed at the next time the gas producer turbine rotor is disassembled for any reason, or within 1,750 hours time-since-last-overhaul, time-since-new, time-since-last-heavy-maintenance, or time-since-last-hot section inspection after the effective date of this AD, whichever occurs first, but no later than October 31, 2011, unless already done.

## Required Actions

(f) If not already installed, install a modified gas producer support assembly to provide installation of the turbine energy absorbing ring. Use paragraph 2. of RRC Alert Commercial Engine Bulletin No. CEB-A-1254, Revision 3, dated May 21, 2004, to do the modification and installation.

                                (g) If not already installed, install a modified 1st stage turbine nozzle, 2nd stage turbine nozzle, and gas producer support assembly to provide installation of the turbine energy absorbing ring. Use paragraph 2. of RRC Alert Commercial Engine Bulletin                                       ( print page 67869)                                    No. CEB-A-1253, Revision 4, dated May 21, 2004, to do the modification and installation.                            

(h) Install a turbine energy absorbing ring in the plane of the 1st stage turbine wheel. Use paragraphs 2.A. and 2.B. of RRC Alert Commercial Engine Bulletin No. CEB-A-1255, Revision 4, dated September 29, 2004, to do the installation.

## Alternative Methods of Compliance

(i) The Manager, Chicago Aircraft 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.

## Related Information

(j) None.

Issued in Burlington, Massachusetts, on November 16, 2004.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.

[FR Doc. 04-25794 Filed 11-19-04; 8:45 am]

BILLING CODE 4910-13-P