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Proposed Rule

Airworthiness Directives; Honeywell International LTS101 Series Turboshaft Engines and LTP101 Series Turboprop 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.

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AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

This supplemental NPRM revises an earlier proposed airworthiness directive (AD), for Honeywell International LTS101-600A series and LTS101-700D-2 turboshaft engines, and LTP101-600A-1A and LTP101-700A-1A turboprop engines with power turbine blades, part number (P/N) 4-141-084-06, installed. That proposed AD would have required removing power turbine blades, P/N 4-141-084-06 from service, using a drawdown schedule specified in that proposed AD. That proposal was prompted by reports of fatigue cracks in the airfoil of the power turbine blade. This action revises the proposed rule by expanding and clarifying the applicability to include more engine models and power turbine blade P/Ns that could have the unsafe condition, and by clarifying the applicability by specifying power turbine rotor P/Ns instead of the blade P/Ns. The actions specified by this proposed AD are intended to prevent fracture of the power turbine blade airfoil, which could result in sudden loss of engine power and prevent continued safe flight or safe landing.

DATES:

We must receive any comments on this proposed AD by February 15, 2011.

ADDRESSES:

Use one of the following addresses to comment on this proposed AD.

  • Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.
  • Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
  • Fax: (202) 493-2251.

Contact Honeywell International Inc., P.O. Box 52181, Phoenix, AZ 85072-2181; telephone (800) 601-3099 (U.S.A.) or (602) 365-3099 (International); or go to: https://portal.honeywell.com/​wps/​portal/​aero, for a copy of the service information identified in this proposed AD.

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FOR FURTHER INFORMATION CONTACT:

Robert Baitoo, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; e-mail: robert.baitoo@faa.gov; telephone (562) 627-5245; fax (562) 627-5210.

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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-2009-1185; Directorate Identifier 2009-NE-24-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://www.regulations.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 Web site, anyone can find and read the comments in any of our dockets, including, if provided, 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).

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​ or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.Start Printed Page 78938

Discussion

The FAA proposed to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an AD, applicable to Honeywell International LTS101-600A series and LTS101-700D-2 turboshaft engines, and LTP101-600A-1A and LTP101-700A-1A turboprop engines. We published the proposed AD in the Federal Register on December 21, 2009 (74 FR 67829). That action proposed to require removing power turbine blades, P/N 4-141-084-06, from service using a specific drawdown schedule. That NPRM was prompted by reports of fatigue cracks in the airfoil of the power turbine blade. That condition, if not corrected, could result in fracture of the power turbine blade airfoil, which could result in sudden loss of engine power.

Since we issued that NPRM, Honeywell International Inc. informed us that power turbine blades, P/N 4-141-084-03, could also have the unsafe condition. Those blades are used in power turbine rotors P/Ns 4-141-290-02 and 4-141-290-16. Based on the information we received from Honeywell International Inc., we also determined that specifying the applicability by power turbine rotors P/N is clearer than by specifying the blade P/N.

Comments

We provided the public the opportunity to participate in the development of that proposed AD. We have considered the comments received on the original NPRM.

Proposed AD Should Apply to Engines on Multi-Engine Helicopters

One commenter, the National Transportation Safety Board (NTSB) asks us to consider adding to the applicability of the proposed AD, engines that also use the affected P/N turbine rotor blade, and are installed on multi-engine helicopters. The NTSB states that loss of power in one of the two engines is a safety issue.

We agree with the NTSB that the fracture of a power turbine airfoil of an LTS101 series turboshaft engine installed on a twin-engine helicopter is a safety issue. We added Honeywell International Inc. LTS101-650B-1, LTS101-650C-3, LTS101-650C-3A, LTS101-750B-1, LTS101-750B-2, LTS101-750C-1, and LTS101-850B-2 turboshaft engines that are installed on twin-engine helicopters to the applicability of the proposed AD. We also added to the applicability, paragraph (g), and Table 1 of the proposed AD, Honeywell International Inc. LTP101-600A-1A and LTP101-700A-1A turboprop engines that use the same blades.

The NTSB also requested that we reduce the drawdown schedule for the affected blades to remove the at risk power turbine rotor blades sooner.

We don't agree. Our risk assessment for the unsafe condition doesn't justify accelerating the drawdown schedules.

Editorial Changes to Table 1 and Table 1 of the Proposed AD

We changed Table 1 and Table 2 in the proposed AD to eliminate arbitrary step changes.

Since these changes expand the scope of the originally proposed rule, we determined that reopening the comment period is appropriate.

FAA's Determination of an Unsafe Condition and Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other Honeywell International Inc. LTS101-600A-2, -3, -3A, LTS101-700D-2, LTS101-650B-1, LTS101-650C-3, LTS101-650C-3A, LTS101-750B-1, LTS101-750B-2, LTS101-750C-1, and LTS101-850B-2 turboshaft engines; and LTP101-600A-1A and LTP101-700A-1A turboprop engines of the same type design, the proposed AD would require removing from service, power turbine rotors, P/Ns 4-141-290-01, -02, -03, -05, -06, -11, -12, -13, -14, or -16, using the compliance drawdown schedule specified in Table 1, and Table 2 of this AD.

Costs of Compliance

We estimate that this proposed AD would affect 240 engines installed on aircraft of U.S. registry. We also estimate that it would take about 30 work-hours per engine to perform the proposed actions, and that the average labor rate is $85 per work-hour. Required parts would cost about $70,000 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $17,412,000.

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 AD:

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. You may get a copy of this summary at the address listed under ADDRESSES.

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List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

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

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

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[Amended]

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

Honeywell International Inc. (Formerly AlliedSignal, Textron Lycoming): Docket No. FAA-2009-1185; Directorate Identifier 2009-NE-24-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by February 15, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Honeywell International LTS101-600A-2, -3, -3A, LTS101-700D-2, LTS101-650B-1, LTS101-650C-3, LTS101-650C-3A, LTS101-750B-1, LTS101-750B-2, LTS101-750C-1, and LTS101-850B-2 turboshaft engines; and LTP101-600A-1A and LTP101-700A-1A turboprop engines with power turbine rotor, part number (P/N) 4-141-290-01, -02, -03, -05, -06, -11, -12, -13, -14, or -16, installed. These engines are installed on, but not limited to, Eurocopter AS350 and BK117 series and Bell 222 series helicopters; and Page Thrush, Air Tractor AT-302, and Pacific Aero 08-600, Piaggio P166 DL3, and Riley International R421 airplanes.Start Printed Page 78939

Unsafe Condition

(d) This AD results from reports of fatigue cracks in the airfoil of the power turbine blade. We are issuing this AD to prevent fracture of the power turbine blade airfoil, which could result in sudden loss of engine power and prevent continued safe flight or safe landing.

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.

(f) For engines with power turbine rotors, P/Ns 4-141-290-11, -12, -13, and -14, marked with “ORI T41881,” on the aft hub in the vicinity of the P/N, no further action is required.

Removing Power Turbine Rotors From LTS101-600A-2, -3, -3A, and LTS101-700D-2 Turboshaft Engines and LTP101-600A-1A and LTP101-700A-1A Turboprop Engines

(g) For LTS101-600A-2, -3, -3A, and LTS101-700D-2 turboshaft engines and LTP101-600A-1A and LTP101-700A-1A turboprop engines, remove power turbine rotors, P/Ns 4-141-290-01, -02, -03, -05, -06, -11, -12, -13, -14, or -16, using the cycles specified in Table 1 of this AD:

Table 1—Drawdown Cycles for LTS101-600A-2, -3, -3A, and LTS101-700D-2 Turboshaft Engines and LTP101-600A-1A and LTP101-700A-1A Turboprop Engines

If power turbine rotor time on the effective date of this AD is * * *Then remove the power turbine rotor from the engine * * *
(1) Fewer than 5,000 cycles-since-new (CSN)Between 5,000 and 5,500 CSN.
(2) 5,000 to 7,899 CSNWithin 500 cycles-in-service (CIS) after the effective date of this AD or before exceeding 8,000 CSN, whichever occurs first.
(3) 7,900 to 9,999 CSNWithin 100 CIS after the effective date of this AD or before exceeding 10,050 CSN, whichever occurs first.
(4) 10,000 or more CSNWithin 50 CIS after the effective date of this AD.

Removing Power Turbine Rotors From LTS101-650B-1, -650C-3,—650C-3A, -750B-1, -2, -750C-1, and -850B-2 Engines

(h) Remove power turbine rotors, P/Ns 4-141-290-01, -02 -03, -05, -06, -11, -12, -13, -14, or -16, using the cycles specified in Table 2 of this AD:

Table 2—Drawdown Cycles for LTS101-650B-1, -650C-3,-650C-3A, -750B-1, -2, -750C-1, and -850B-2 Engines

If power turbine rotor time on the effective date of this AD is * * *Then remove the power turbine rotor from the engine * * *
(1) Fewer than 5,500 CSNBetween 5,000 and 7,200 CSN.
(2) 5,500 to 7,999 CSNWithin 1,700 CIS after the effective date of this AD or before exceeding 8,950 CSN, whichever occurs first.
(3) 8,000 to 9,999 CSNWithin 950 CIS after the effective date of this AD or before exceeding 10,400 CSN, whichever occurs first.
(4) 10,000 or more CSNWithin 400 CIS after the effective date of this AD.

Alternative Methods of Compliance

(i) The Manager, Los Angles 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) Contact Robert Baitoo, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; e-mail: robert.baitoo@faa.gov; telephone (562) 627-5245; fax (562) 627-5210, for more information about this AD.

(k) Honeywell International Inc. Service Bulletins LT 101-71-00-0252 and LTS101-71-00-0253, pertain to the subject of this AD. Contact Honeywell International Inc., P.O. Box 52181, Phoenix, AZ 85072-2181; telephone (800) 601-3099 (U.S.A.) or (602) 365-3099 (International); or go to: https://portal.honeywell.com/​wps/​portal/​aero, for a copy of this service information.

Start Signature

Issued in Burlington, Massachusetts, on December 13, 2010.

Thomas A. Boudreau,

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

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[FR Doc. 2010-31782 Filed 12-16-10; 8:45 am]

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