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Proposed Rule

Airworthiness Directives; General Electric Company (GE) CF34-1A, CF34-3A, and CF34-3B Series Turbofan Engines

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AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for GE CF34-1A, CF34-3A, and CF34-3B series turbofan engines. This proposed AD would require: Removing from service certain part number (P/N) and serial number (SN) fan blades within compliance times specified in this proposed AD, inspecting the fan blade abradable rub strip on certain engines for wear, inspecting the fan blades on certain engines for cracks, and inspecting the aft actuator head hose fitting for correct position, and if necessary repositioning. This proposed AD results from a report of an under-cowl fire, and a failed fan blade. We are proposing this AD to prevent failure of certain P/N and SN fan blades and aft actuator head hoses, which could result in an under-cowl fire and subsequent damage to the airplane.

DATES:

We must receive any comments on this proposed AD by June 8, 2009.

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.

You can get the service information identified in this proposed AD from General Electric Company via Lockheed Martin Technology Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215, telephone (513) 672-8400, fax (513) 672-8422.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Kenneth Steeves, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: kenneth.steeves@faa.gov; telephone (781) 238-7765; fax (781) 238-7199.

End Further Info End Preamble Start Supplemental Information

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-2009-0328; Directorate Identifier 2008-NE-44-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.

Discussion

We have received reports of certain P/N and SN fan blades failing on CF34 series engines. The first failure also included an under-cowl fire that caused extensive damage to the engine. Although we haven't been able to determine the exact cause of the under-cowl fire because of the thermal damage, the investigation revealed two problems; a fan blade failed at the platform tang and the aft actuator head hose failed. The investigation also revealed that the accessory gearbox had separated from the engine, possibly contributing to the actuator hose failure.

We traced the failed fan blades to a specific supplier and their billet material. The investigation found that the billet alloy material met specifications and the supplier's approved processes were different from other suppliers' approved processes. The differences allowed a larger area of aligned alpha colonies to form in the tang region of the fan blade. If the alpha colonies align, they can cause cracks in the blade tang. Although the material was within specification, and the processes and billet size conformed to the engineering drawings for the blades, GE determined that the material, process, and billet size combined to allow the alpha colonies to align. The investigation also found that although the aft actuator hose is designed to include enough slack to prevent its failure if the gearbox separates from the engine, the incorrect orientation of the aft actuator head hose fitting at the main fuel control removed that slack. The incorrect position of the fitting might have caused the hose to fail and contribute to fire.

This condition, if not corrected, could result in failure of certain P/N and SN fan blades and aft actuator head hoses, which could result in an under-cowl fire and subsequent damage to the airplane.

Relevant Service Information

We have reviewed and approved the technical contents of the following GE Aircraft Engines Service Bulletins (SBs):

  • CF34-AL S/B 73-0046, Revision 02, dated August 27, 2008, and CF34-BJ S/B 73-0062, Revision 02, dated August 27, 2008, that provide instructions for inspecting the orientation of the aft actuator hose assembly and the main fuel control.
  • CF34-AL S/B 72-0245, Revision 01, dated July 3, 2008, CF34-BJ S/B 72-0229, Revision 01, dated July 30, 2008, and CF34-BJ S/B 72-0230, Revision 01, dated July 30, 2008, that provide instructions for replacing certain existing blades, P/Ns 6018T30P14 and 4923T56G08, that have a SN listed in Appendix A of those SBs.
  • CF34-AL S/B 72-0250, Revision 01, dated November 26, 2008, and CF34-BJ S/B 72-0231, Revision 02, dated November 26, 2008, that provide instructions for inspecting the fan case abradable rub strip and fan blade tangs.Start Printed Page 15897

Differences Between the Proposed AD and the Manufacturer's Service Information

  • Service Bulletin CF34-AL S/B 73-0046, Revision 02, dated August 27, 2008 recommends performing the inspection at the next “A” check, but no later than 750 hours time-in-service (TIS). This proposed AD would require performing the inspection within 750 hours TIS after the effective date of the proposed AD.
  • Service Bulletin CF34-BJ S/B 73-0062, Revision 02, dated August 27, 2008, recommends performing the inspection of the CF34-3A1 engines at the next scheduled 300 hour check, but no later than 600 hours. This proposed AD would require performing the inspection within 300 hours TIS after the effective date of the proposed AD.
  • Service Bulletin CF34-BJ S/B 73-0062, Revision 02, dated August 27, 2008, recommends performing the inspection of the CF34-3B engines at the next scheduled 400 hour check but no later than 800 hours TIS. This proposed AD would require performing the inspection within 400 hours TIS after the effective date of the proposed AD.
  • Service Bulletin CF34-AL S/B 72-0250, Revision 01, dated November 26, 2008, recommends inspection of the fan blades if there is a continuous 360 degree rub indication. This proposed AD would require the inspection of the fan blades if there is a continuous 360 degree rub indication. The service bulletin also contains an alternate compliance method using GE's remote diagnostics trend monitoring program. This proposed AD does not include that alternate method.

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:

  • Removing from service certain P/N and SN blades within compliance times specified in this proposed AD.
  • Inspecting the fan blade abradable rub strip on certain engines for wear.
  • Inspecting the fan blades on certain engines for cracks.
  • Inspecting the aft actuator head hose fitting for correct position, and if necessary, repositioning.

The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

We estimate that this proposed AD would affect 1,966 engines installed on airplanes of U.S. registry. We estimate that the fan blade inspection and replacement requirement would affect 300 of these engines, and the actuator head hose inspection would affect 1,662 engines. We also estimate that it would take 0.5 work-hour per engine to inspect the fan blade abradable rub strip, 6 work-hours per engine to visually inspect the fan blades, 11 work-hours per engine to perform an eddy current inspection of the fan blades, and 0.25 work-hour per engine to inspect the actuator head hose fitting, and that the average labor rate is $80 per work-hour. Required parts would cost $51,106,600. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $51,184,000.

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 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

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:

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PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[Amended]

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

General Electric Company: Docket No. FAA-2009-0328; Directorate Identifier 2008-NE-44-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by June 8, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to General Electric Company (GE) CF34-1A, CF34-3A, CF34-3A1, CF34-3A2, CF34-3B, and CF34-3B1 turbofan engines. These engines are installed on, but not limited to, Bombardier Canadair Models CL-600-2A12, CL-600-2B16, and CL-600-2B19 airplanes.

Unsafe Condition

(d) This AD results from a report of an under-cowl fire, and a failed fan blade. We are issuing this AD to prevent failure of certain part number (P/N) and serial number (SN) fan blades and aft actuator head hoses, which could result in an under-cowl fire and subsequent damage to the airplane.

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.

CF34-3A1 and CF34-3B1 Engines

(f) For CF34-3A1 engines with fan drive shaft, P/N 6036T78P02, and airworthiness limitation section life limit of 22,000 CSN, and CF34-3B1 engines with fan blades, P/Ns 6018T30P14 or 4923T56G08, that have a fan Start Printed Page 15898blade SN listed in Appendix A of GE Aircraft Engines (GEAE) Service Bulletin (SB) CF34-AL S/B 72-0245, Revision 01, dated July 3, 2008, do the following:

(1) Remove fan blades from service within 4,000 cycles-in-service (CIS) after the effective date of this AD or by December 31, 2010, whichever occurs first.

Initial Visual Inspection of the Fan Blade Abradable Rub Strip for Wear

(2) For fan blades with 1,200 or more cycles-since-new (CSN) on the effective date of this AD, within 20 CIS after the effective date of this AD, perform an initial visual inspection of the fan blade abradable rub strip for wear. Use paragraphs 3.A.(1) through 3.A.(2) of the Accomplishment Instructions of GEAE SB CF34-AL S/B 72-0250, Revision 01, dated November 26, 2008, to perform the inspection.

(3) For fan blades with fewer than 1,200 CSN on the effective date of this AD, within 1,220 CSN, perform an initial visual inspection of the fan blade abradable rub strip for wear. Use paragraphs 3.A.(1) through 3.A.(2) of the Accomplishment Instructions of GEAE SB CF34-AL S/B 72-0250, Revision 01, dated November 26, 2008, to perform the inspection.

(4) If you find a continuous 360 degree rub indication, before further flight, visually inspect the fan blades using paragraphs 3.A.(2)(a) through 3.A.(2)(b) of the Accomplishment Instructions of GEAE SB CF34-AL S/B 72-0250, Revision 01, dated November 26, 2008, to perform the inspection.

(5) If you find a crack in the retaining pin holes of the fan blade, remove the blade from service.

Repetitive Visual Inspection of the Fan Blade Abradable Rub Strip for Wear

(6) Within 75 cycles-since-last inspection (CSLI) or 100 hours-since-last-inspection (HSLI), whichever occurs later, perform a visual inspection of the fan blade abradable rub strip for wear. Use paragraphs 3.A.(1) through 3.A.(2) of the Accomplishment Instructions of GEAE SB CF34-AL S/B 72-0250, Revision 01, dated November 26, 2008, to perform the inspection.

(i) If you find a continuous 360 degree rub indication, before further flight, visually inspect the fan blades using paragraphs 3.A.(2)(a) through 3.A.(2)(b) of the Accomplishment Instructions of GEAE SB CF34-AL S/B 72-0250, Revision 01, dated November 26, 2008, to perform the inspection.

(ii) If you find a crack in the retaining pin holes of the fan blade, remove the blade from service.

Inspection of the Aft Actuator Head Hose Fitting on CF34-3A1 and CF34-3B1 Engines

(7) Within 750 hours time in service (TIS) after the effective date of this AD, visually inspect and, if necessary, reposition the aft actuator head hose fitting. Use paragraph 3.A of the Accomplishment Instructions of GEAE SB CF34-AL S/B 73-0046, Revision 02, dated August 27, 2008, to perform the inspection.

CF34-1A, CF34-3A, CF34-3A2, CF34-3B, and CF34-3A1 Engines

(g) For CF34-3A1 engines with fan drive shaft, P/N 6036T78P02, and airworthiness limitation section life limit of 15,000 CSN, and CF34-1A, CF34-3A, CF34-3A2, and CF34-3B engines with fan blades, P/N 6018T30P14 or P/N 4923T56G08, that have a fan blade SN listed in Appendix A of GEAE SB CF34-BJ S/B 72-0229, Revision 01, dated July 30, 2008, do the following:

(1) Remove fan blades, P/N 6018T30P14, from service within 2,400 CSN.

(2) Remove fan blades, P/N 4923T56G08, from service within 1,200 CIS since the bushing repair of the fan blade hole.

Initial Eddy Current Inspection of the Fan Blades

(3) For fan blades, P/N 6018T30P14, with more than 850 CSN, but fewer than 1,200 CSN on the effective date of this AD, within 350 CIS after the effective date of this AD, perform an initial eddy current inspection (ECI) of the fan blades for cracks. Use paragraphs 3.A. or 3.B. of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 72-0229, Revision 01, dated July 30, 2008, to perform the inspection.

(4) For fan blades, P/N 6018T30P14, with 850 or fewer CSN on the effective date of this AD, within 1,200 CSN, perform an initial ECI of the fan blades for cracks. Use paragraphs 3.A. or 3.B. of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 72-0229, Revision 01, dated July 30, 2008, to perform the inspection.

(5) If you find a crack in the retaining pin holes of the fan blade, remove the blade from service.

Repetitive ECI of the Fan Blades

(6) For fan blades, P/N 6018T30P14, installed, within 600 CSLI, perform an ECI of the fan blades for cracks. Use paragraphs 3.A. or 3.B. of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 72-0229, Revision 01, dated July 30, 2008, to perform the inspection.

(7) If you find a crack in the retaining pin holes of the fan blade, remove the blade from service.

Initial Visual Inspection of the Fan Blade Abradable Rub Strip for Wear

(8) For engines with fan blades, P/N 6018T30P14, installed that have a fan blade SN listed in Appendix A of GEAE SB CF34-BJ S/B 72-0229, Revision 01, dated July 30, 2008, with 1,200 or more CSN on the effective date of this AD, that haven't had an ECI of the fan blades for cracks, do the following:

(i) Perform an initial inspection of the fan blade abradable rub strip for wear within 20 CIS after the effective date of this AD. Use paragraph 3.A.(1) of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 72-0231, Revision 02, dated November 26, 2008, to perform the inspection.

(ii) If you find a continuous 360 degree rub indication, before further flight, perform a visual inspection of the fan blades for cracks. Use paragraphs 3.A(2)(a) or 3.A(2)(b) of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 72-0231, Revision 02, dated November 26, 2008, to perform the inspection.

(iii) If you find a crack in the retaining pin holes of the fan blade, remove the blade from service.

Repetitive Inspection of the Fan Blade Abradable Rub Strip for Wear

(9) For engines with fan blades, P/N 6018T30P14, installed, if you have performed an ECI of the fan blade, you don't need to inspect the fan blade abradable rub strip for wear.

(10) For engines with fan blades, P/N 6018T30P14, installed, within 75 CSLI or 100 HSLI, whichever occurs later, do the following:

(i) Perform a visual inspection of the fan blade abradable rub strip for wear. Use paragraph 3.A.(1) of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 72-0231, Revision 02, dated November 26, 2008, to perform the inspection.

(ii) If you find a continuous 360 degree rub indication, before further flight, visually inspect the fan blades using paragraphs 3.A.(2)(a) through 3.A.(2)(b) of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 72-0231, Revision 02, dated November 26, 2008.

(iii) If you find a crack in the retaining pin holes of the fan blade, remove the blade from service.

Inspection of the Aft Actuator Head Hose Fitting on CF34-3A1 and CF34-3B Engines

(11) For CF34-3A1 engines, within 300 hours TIS after the effective date of this AD, visually inspect and, if necessary, reposition the aft actuator head hose fitting. Use paragraph 3.A of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 73-0062, Revision 02, dated August 27, 2008, to perform the inspection.

(12) For CF34-3B engines, within 400 hours TIS after the effective date of this AD, visually inspect and if necessary, reposition the aft actuator head hose fitting. Use paragraph 3.A of the Accomplishment Instructions of GEAE SB CF34-BJ S/B 73-0062, Revision 02, dated August 27, 2008, to perform the inspection.

Credit for Previous Actions

(h) Inspections previously performed using the following GEAE SBs meet the requirements specified in the indicated paragraphs:

(1) CF34-AL S/B 72-0250, dated August 15, 2008, meet the requirements specified in paragraphs (f)(2) through (f)(4) of this AD.

(2) CF34-AL S/B 73-0046, Revision 01, dated July 1, 2008, or earlier issue, meet the requirements specified in paragraph (f)(7) of this AD.

(3) CF34-BJ S/B 72-0229, dated April 10, 2008, meet the requirements specified in paragraphs (g)(3) and (g)(4) of this AD.

(4) CF34-BJ S/B 72-0231, Revision 01, dated October 1, 2008, or earlier issue, meet the requirements specified in paragraphs (g)(10)(i) and (g)(10)(ii) of this AD.

(5) CF34-BJ S/B 73-0062, Revision 01, dated July 1, 2008, or earlier issue, meet the requirements specified in paragraphs (g)(11) and (g)(12) of this AD.Start Printed Page 15899

Installation Prohibitions

(i) After the effective date of this AD:

(1) Do not install any fan blade into any CF34-3A1 engine with fan drive shaft, P/N 6036T78P02, with an airworthiness limitation section life limit of 22,000 CSN if that fan blade:

(i) Was installed in a CF34-3A1 engine with fan drive shaft, P/N 6036T78P02, with an airworthiness limitation section life limit of 15,000 CSN; and

(ii) Is listed in Appendix A of GEAE SB CF34-BJ S/B 72-0229, Revision 01, dated July 30, 2008; or

(iii) Is listed in Appendix A of GEAE SB CF34-BJ S/B 72-0230, Revision 01, dated July 30, 2008.

(2) Do not install any fan blade into any CF34-3A1 engine with fan drive shaft, P/N 6036T78P02, with an airworthiness limitation section life limit of 15,000 CSN if that fan blade:

(i) Was installed in any CF34-3A1 engine with fan drive shaft, P/N 6036T78P02, with an airworthiness limitation section life limit of 22,000 CSN and,

(ii) Is listed in Appendix A of GEAE SB CF34-AL S/B 72-0245, Revision 01, dated July 3, 2008.

Alternative Methods of Compliance

(j) The Manager, Engine 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

(k) Contact Kenneth Steeves, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: kenneth.steeves@faa.gov; telephone (781) 238-7765; fax (781) 238-7199, for more information about this AD.

(l) GE Aircraft Engines SBs CF34-AL S/B 73-0046, Revision 02, dated August 27, 2008; CF34-AL S/B 72-0245, Revision 01, dated July 3, 2008; CF34-AL S/B 72-0250, dated August 15, 2008; CF34-BJ S/B 73-0062, Revision 02, dated August 27, 2008; CF34-BJ S/B 72-0229, Revision 01, dated July 30, 2008; CF34-BJ S/B 72-0230, Revision 01, dated July 30, 2008; and CF34-BJ S/B 72-0231, Revision 01, dated October 1, 2008; pertain to the subject of this AD. Contact General Electric Company via Lockheed Martin Technology Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215; telephone (513) 672-8400; fax (513) 672-8422, for a copy of this service information.

Start Signature

Issued in Burlington, Massachusetts, on April 4, 2009.

Peter A. White,

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

End Signature End Part End Supplemental Information

[FR Doc. E9-8070 Filed 4-6-09; 11:15 am]

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