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Proposed Rule

Airworthiness Directives; Bell Helicopter Textron Canada Model 430 Helicopters

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Federal Aviation Administration, DOT.


Notice of proposed rulemaking (NPRM).


This document proposes the adoption of a new airworthiness directive (AD) for Bell Helicopter Textron Canada (BHTC) Model 430 helicopters. This proposal would require modifying the electrical system. This proposal is prompted by the loss of electrical power due to design deficiencies discovered during single-pilot Instrument Flight Rules (IFR) flight testing. The actions specified by the proposed AD are intended to prevent loss of electrical power and subsequent loss of control of the helicopter.


Comments must be received on or before October 10, 2000.


Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-22-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: Comments may be inspected at the Office of the Regional Counsel between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

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Robert McCallister, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, Fort Worth, Texas 76193-0110; telephone (817) 222-5121, fax (817) 222-5961.

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Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their mailed comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2000-SW-22-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-22-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.


Transport Canada, the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on BHTC Model 430 helicopters. Transport Canada advises that an evaluation during the single-pilot IFR evaluation of the electrical system revealed several areas that did not comply with the Canadian Aviation Regulations.

BHTC has issued Bell Helicopter Textron Alert Service Bulletin No. 430-99-10, dated December 16, 1999 (ASB), which specifies implementing electrical power distribution system improvements at the next annual (600-hour) inspection but not later than December 31, 2000. Transport Canada classified this ASB as mandatory and issued AD No. CF-2000-08, dated March 21, 2000, to ensure the continued airworthiness of these helicopters in Canada.

This helicopter model is manufactured in Canada and is type certificated for operation in the United States under the provisions of 14 CFR 21.29 and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, Transport Canada has kept the FAA informed of the situation described above. The FAA has examined the findings of Transport Canada, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

We have identified an unsafe condition that is likely to exist or develop on other BHTC Model 430 helicopters of the same type design registered in the United States. The proposed AD would require implementing the following electrical system changes in accordance with the ASB:

  • Modify the electrical bus distribution system to include emergency, essential and nonessential busses. Relocate electrical system circuit breakers accordingly.
  • Add a second redundant aircraft DC power supply with associated circuit breaker for each full authority digital engine control electronic control unit.
  • Modify AC inverter switching logic to prevent inadvertent loss of AC power.
  • Modify electrical bonding of the DC generator ground circuits by increasing the size of the hardware securing the ground shunt bus bar to the airframe structure.

The FAA estimates that 3 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 140 work hours per helicopter to accomplish the proposed actions, and that the average labor rate is $60 per work hour. The manufacturer states in the ASB that they will provide the 100 percent warranty credit for the parts and will allow a maximum Start Printed Page 48646warranty credit of $7700 for labor costs. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $2100 assuming the stated credit for parts and labor.

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this 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) if promulgated, will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

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List of Subjects in 14 CFR Part 39

  • Air transportation
  • Aircraft
  • Aviation safety
  • Safety
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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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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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2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

Bell Helicopter Textron Canada: Docket No. 2000-SW-22-AD.

Applicability: Model 430 helicopters, serial numbers 49002, 49004 through 49006, 49008 through 49016, 49018 through 49025, and 49027 through 49036, certificated in any category.

Note 1:

This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required at the next 600-hour inspection or before further flight after December 31, 2000, whichever occurs first, unless accomplished previously.

To prevent loss of electrical power and subsequent loss of control of the helicopter, accomplish the following:

(a) Modify the electrical system in accordance with the Accomplishment Instructions, paragraphs 1 through 6, of Bell Helicopter Textron Alert Service Bulletin No. 430-99-10, dated December 16, 1999.

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Regulations Group, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Regulations Group.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Regulations Group.

(c) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be accomplished.

Note 3:

The subject of this AD is addressed in Transport Canada, Canada, AD CF-2000-08, dated March 21, 2000.

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Issued in Fort Worth, Texas, on August 1, 2000.

Henry A. Armstrong,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 00-20182 Filed 8-8-00; 8:45 am]