Federal Aviation Administration (FAA), DOT.
Notice of proposed rulemaking (NPRM).
The FAA proposes to supersede an existing airworthiness directive (AD) for RRC models 250-C30R/3, -C30R/3M, -C47B, and -C47M turboshaft engines. That AD currently requires initial and repetitive electrical signal inspections of the hydromechanical unit (HMU) Power Lever Angle (PLA) potentiometer. This proposed AD would continue to require those inspections and would add replacement of the existing HMU with a new design HMU as a mandatory terminating action to the repetitive inspection requirements. This proposed AD results from the manufacturer releasing a redesigned HMU that has a dual-element potentiometer. We are proposing this AD to prevent uncommanded and sudden changes in engine power.
We must receive any comments on this proposed AD by August 9, 2004.
Use one of the following addresses to submit comments on this proposed AD:
- By mail: Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-NE-23-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
- By fax: (781) 238-7055.
- By e-mail: email@example.com.
You may get the service information referenced in this 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 AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Khailaa Hosny, Aerospace Engineer, Chicago Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des Plaines, IL 60018-4696; telephone (847) 294-7134; fax (847) 294-7834.End Further Info End Preamble Start Supplemental Information
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 “AD Docket No. 2003-NE-23-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. If a person contacts us verbally, and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.
We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You may get more information about plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.
Examining the AD Docket
You may examine the AD Docket (including any comments and service information), by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for the location.
On June 19, 2003, we issued AD 2003-13-10, Amendment 39-13210 (68 FR 38590, June 30, 2003). That AD requires initial and repetitive inspections of the electrical signal from the HMU PLA potentiometer. That AD resulted from an investigation by the NTSB into uncommanded and sudden changes in engine power on a Bell 407 helicopter on March 27, 2003. The NTSB investigation revealed that a potential undetected failure of the electrical signal from the PLA potentiometer, provided by the HMU of the full-authority digital-electronic control (FADEC) system, could cause uncommanded and sudden changes in engine power.
Actions Since AD 2003-13-10 Was Issued
The manufacturer has released a new design HMU that incorporates a dual-element potentiometer. The dual-element function lessens the unsafe condition associated with the single-element design.
Relevant Service Information
We have reviewed and approved the technical contents of RRC Service Bulletins (SBs) CEB A-73-3103, Revision 4, dated December 2, 2003, and CEB A-73-6030, Revision 4, dated December 2, 2003; that describe procedures for inspecting the PLA potentiometer signal.
Differences Between This Proposed AD and the Manufacturer's Service Information
Although the combined RRC SB CEB A-73-3103 (250-C30 engines) and CEB A-73-6030 (250-C47 engines), Revision 4, dated December 2, 2003, also includes CEB A-73-5021 for 250-C40 engines, this AD is not applicable to the 250-C40 engine model because the 250-C40 engine model is used in twin-engine applications.
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: Start Printed Page 32288
- An initial inspection of the electrical signal of the HMU PLA potentiometer within 300 flight hours (FH) after the effective date of this AD and;
- Repetitive inspections every 300 FH until the single-element HMU is replaced with the dual-element HMU, and;
- Replacing the single-element HMU with a dual-element HMU within 600 FH after the effective date of the AD, or by January 30, 2005, whichever occurs earlier.
The proposed AD would require that you do these inspections using the service information described previously.
Costs of Compliance
We estimate that 700 engines installed on helicopters of U.S. registry would be affected by this proposed AD. We estimate that it would take about 4 work hours per engine to replace a single-element HMU with a dual-element HMU. We also estimate that 15 percent of the single-element HMU's would fail the required inspection and require replacing the HMU. The average labor rate is $65 per work hour. Required parts would cost approximately $615 per engine. Based on these figures, we estimate the total cost of the proposed AD to U.S. operators to be $704,375.
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 by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2003-NE-23-AD” in your request.Start List of Subjects
List of Subjects in 14 CFR Part 39
- Air transportation
- Aviation safety
The Proposed Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 14 CFR part 39 as follows:Start Part
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. The FAA amends § 39.13 by removing Amendment 39-13210 (68 FR 38590, June 30, 2003) and by adding a new airworthiness directive to read as follows:
Rolls-Royce Corporation (formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison): Docket No. 2003-NE-23-AD. Supersedes AD 2003-13-10, Amendment 39-13210.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive comments on this airworthiness directive (AD) action by August 9, 2004.
(b) This AD Supersedes AD 2003-13-10.
(c) This AD is applicable to Rolls-Royce Corporation (formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison) (RRC) models 250-C30R/3, -C30R/3M, -C47B, and -C47M turboshaft engines that have a hydromechanical unit (HMU) with a part number (P/N) listed in 1.A. Group A of RRC Alert Commercial Engine Bulletin (ACEB) No. CEB A-72-3103, Revision 4, dated December 2, 2003; and CEB A-72-6030, Revision 4, dated December 2, 2003. These engines are installed on, but not limited to, Bell OH-58D, Bell Helicopter Textron 407, Boeing AH/MH-6M, and MD Helicopters Inc. 600N helicopters.
(d) This AD results from the manufacturer releasing a redesigned HMU that has a dual-element potentiometer. We are issuing this AD to prevent uncommanded and sudden changes in engine power.
(e) Compliance with this AD is required as indicated, unless already done.
(f) Perform an initial electrical signal inspection of the hydromechanical unit (HMU) PLA potentiometer, within 300 flight hours (FH) after the effective date of this AD. Use paragraphs 2.B. through 2.B.(8) and 2.B.(10) of the Accomplishment Instructions of RRC ACEB No. CEB A-73-3103, Revision 4, dated December 2, 2003; or CEB A-73-6030, Revision 4, dated December 2, 2003; to perform the inspection.
(g) Replace the HMU before further flight if the electrical signal inspection result is unacceptable.
(h) Thereafter, perform repetitive electrical signal inspections of the HMU PLA potentiometer within 300 FH of the last inspection. Use paragraphs 2.B. through 2.B.(8) and 2.B.(10) of the Accomplishment Instructions of RRC ACEB No. CEB A-73-3103, Revision 4, dated December 2, 2003; or CEB A-73-6030, Revision 4, dated December 2, 2003; to perform the inspection.
(i) Replace the HMU before further flight if the electrical signal inspection is unacceptable.
Mandatory Terminating Action
(j) Replace the HMU with an HMU that has a P/N not specified in this AD within 600 FH after the effective date of this AD, or January 31, 2005, whichever occurs earlier. Replacing the HMU with an HMU that has a P/N not specified in this AD terminates the repetitive inspection requirement specified in paragraph (h) of this AD.
Alternative Methods of Compliance
(k) The Manager, Chicago Aircraft Certification Office, FAA, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.
Material Incorporated by Reference
Issued in Burlington, Massachusetts, on June 3, 2004.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.
[FR Doc. 04-13010 Filed 6-8-04; 8:45 am]
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