05-22437. Airworthiness Directives; Rolls-Royce Corporation (formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison) 250-B and 250-C Series Turboprop and Turboshaft Engines

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for Rolls-Royce Corporation 250-B and 250-C series turboprop and turboshaft engines with certain part numbers (P/Ns) of gas producer rotor assembly tie bolts manufactured by EXTEX Ltd., Pacific Sky Supply Inc., Rolls-Royce Corporation (RRC), and Superior Air Parts Inc. This proposed AD would require operators to remove from service affected gas producer rotor assembly tie bolts. This proposed AD results from eleven reports of RRC tie bolt failure due to high cycle fatigue. We are proposing this AD to prevent tie bolt failure that could cause loss of engine power, resulting in a first stage turbine wheel overspeed and an uncontained engine failure.

DATES:

We must receive any comments on this proposed AD by January 9, 2006.

ADDRESSES:

Use one of the following addresses to comment 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 20590-0001.
• Fax: [phone].
• 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 may examine the comments on this proposed AD in the AD docket on the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT:

• Robert Baitoo, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; telephone: [phone], fax: [phone], for questions about, EXTEX Ltd., or Pacific Sky Supply Inc. gas producer rotor assembly tie bolts.
• John Tallarovic, Aerospace Engineer, Chicago Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, IL 60018-4696; telephone [phone]; fax [phone], for questions about RRC gas producer rotor assembly tie bolts.
• Jurgen Priester, Aerospace Engineer, Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, Texas, 76137-4298, telephone [phone], fax [phone], for questions about Superior Air Part Inc. gas producer rotor assembly tie bolts.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send us any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2005-22594; Directorate Identifier 2005-NE-28-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 DOT 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 DOT Docket Offices between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone [phone]) 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 Docket Management Facility receives them.

Discussion

The FAA has received eleven reports of failures of RRC manufactured tie bolts due to high cycle fatigue. The FAA believes that all of these failures are due to the inherent design of the part, which is also common to all of the PMA parts. Therefore, this AD requires removal of all RR and PMA tie-bolts. RRC has redesigned the tie bolt to minimize the risk of failure by high cycle fatigue. RRC manufactured these tie bolts under type and production certificate authority. EXTEX Ltd., Pacific Sky Supply Inc., and Superior Air Parts Inc. each independently manufactured replacement gas producer rotor assembly tie bolts under Parts Manufacturer Approval (PMA) authority. There have been no reported failures of PMA parts. The engines are installed in single-engine helicopters, along with several turboprop airplanes. This condition, if not corrected, could cause loss of engine power, resulting in a first stage turbine wheel overspeed and an uncontained engine failure.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information from the four manufacturers' safety assessments and have identified an unsafe condition that is likely to exist or develop in other RRC 250-B17, -B17B, -B17C, -B17D, -B17E, -B17F, -B17F/1, -B17F/2, 250-C18, -C20, -C20B, -C20F, -C20J, -C20R, -C20R/1, -C20R/2, -C20R/4, -C20S, and -C20W series turboprop and turboshaft engines that have any of the following gas producer rotor assembly tie bolts installed:

• EXTEX Ltd.: P/N A23008020, and E23008020
• Pacific Sky Supply Inc.: P/N 23008020P
• Rolls-Royce Corporation: P/Ns 23008020, 6843388 and 6876991
• Superior Air Parts Inc.: P/N A23008020

We are proposing this AD, which would remove these P/N gas producer rotor assembly tie bolts as specified in the compliance section of this proposed AD.

Costs of Compliance

About 4,000 RRC 250-B and 250-C Series turboprop and turboshaft engines with affected P/Ns of gas producer rotor assembly tie bolts manufactured by EXTEX Ltd., Pacific Sky Supply Inc., Rolls-Royce Corporation (RRC), and Superior Air Parts Inc. are in the worldwide fleet. We estimate that 700 engines installed on aircraft of U.S. registry would be affected by this proposed AD. We also estimate that it would take about 20 work hours per engine to perform the proposed actions, and that the average labor rate is $65 per work hour. Required parts would cost about $421 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $1,204,700.

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 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 regulatory evaluation of the estimated costs to comply with this proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

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

[Amended]

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

Rolls-Royce Corporation (formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison): Docket No. FAA-2005-22594; Directorate Identifier 2005-NE-28-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by January 9, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Rolls-Royce Corporation (formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison) 250-B17, -B17B, -B17C, -B17D, -B17E, -B17F, -B17F/1, -B17F/2, 250-C18, -C20, -C20B, -C20F, -C20J, -C20R, -C20R/1, -C20R/2, -C20R/4, -C20S, and -C20W series turboprop and turboshaft engines with the gas producer rotor assembly tie bolt part numbers (P/Ns) listed in the following Table 1, installed:

Table 1.—Affected Gas Producer Rotor Assembly Tie Bolts

Manufacturer	Affected part Nos.
EXTEX Ltd. (EXTEX)	A23008020 and E23008020.
Rolls-Royce Corporation (RRC)	23008020, 6843388 and 6876991.
Superior Air Parts Inc. (SAP)	A23008020.
Pacific Sky Supply Inc	23008020P.

These engines are installed on, but not limited to, aircraft in the following Table 2:

Table 2.—Applicable Aircraft

Helicopter	Models
Agusta	A109, A109A, A109A II, A109C.
Arrow Falcon Exporters	OH-58A+ and OH-58C.
Bell Textron	206A, 206B, 206L.
Enstrom	TH-28, 480, 480B.
Eurocopter France	AS355E, AS355F, AS355F1, AS355F2.
Eurocopter Deutschland	BO-105A, BO-105C, BO-105S.
FH-1100 Manufacturing Corp	FH-1100.
Garlick	OH-58A+ and OH-58C.
McDonnell Douglas Company	369D, 369E, 369F, 369H, 369HM, 369HS, 369HE, 500N.
San Joaquin	OH-58A+ and OH-58C.
Schweizer	269D.
Aircraft	Models
B-N Group Ltd	BN-2T and BN-2T-4R.
SIAI Marchetti s.r.l	SF600, SF600A.

Unsafe Condition

(d) This AD results from eleven reports of RRC tie bolt failure due to high cycle fatigue. We are issuing this AD to prevent tie bolt failure that could cause loss of engine power, resulting in a first stage turbine wheel overspeed and an uncontained engine failure.

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.

Remove Gas Producer Rotor Assembly Tie Bolts

(f) Remove the P/N gas producer rotor assembly tie bolts listed in Table 1 of this AD from service the next time they are disassembled for any reason, or by October 31, 2011, whichever occurs first.

(g) After the effective date of this AD, do not install any gas producer rotor assembly tie bolt P/Ns listed in Table 1 of this AD in any RRC 250-B and 250-C Series turboprop and turboshaft engines.

Alternative Methods of Compliance

(h) The Manager, Los Angeles Aircraft Certification Office, has the authority to approve alternative methods of compliance for EXTEX, and Pacific Sky Supply Inc. gas producer rotor assembly tie bolts addressed in this AD, if requested, using the procedures found in 14 CFR 39.19. The Manager, Chicago Aircraft Certification Office, has the authority to approve alternative methods of compliance for RRC gas producer rotor assembly tie bolts addressed in this AD, if requested, using the procedures found in 14 CFR 39.19. The Manager, Southwest Special Certification Office, has the authority to approve alternative methods of compliance for SAP gas producer rotor assembly tie bolts addressed in this AD, if requested, using the procedures found in 14 CFR 39.19.

Material Incorporated by Reference

(i) None.

Related Information

(j) RRC Commercial Engine Bulletin (CEB) CEB A-304, CEB A-1371, CEB A-72-4076, TP CEB A-176, TP CEB A-1319, TP CEB A-72-2027, Revision N/C dated May 23, 2005, and EXTEX Service Bulletin T-090, Revision N/C, dated May 23, 2005, pertain to the subject of this AD.

Issued in Burlington, Massachusetts, on November 4, 2005.

Peter A. White,

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