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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 99-SW-84-AD] 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Notice of proposed rulemaking (NPRM). 

# SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Bell Helicopter Textron Canada (BHTC) Model 430 helicopters. This proposal would require replacing arm clamp screws (screws) in the yaw, roll, pitch, and collective syncro resolvers, and installing a guard bracket on the yaw, roll, pitch, and collective syncro resolvers. This proposal is prompted by an operator's report that a yaw control channel jammed during freedom-of-control checks following maintenance. The actions specified by the proposed AD are intended to prevent a jammed flight control and subsequent loss of control of the helicopter. 

# DATES:

Comments must be received on or before July 3, 2000. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 99-SW-84-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: 9-asw-adcomments@faa.gov. Comments may be inspected at the Office of the Regional Counsel between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. 

# FOR FURTHER INFORMATION CONTACT:

Sharon Miles, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations Group, Fort Worth, Texas 76193-0111, telephone (817) 222-5122, fax (817) 222-5961. 

# SUPPLEMENTARY INFORMATION:

## 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 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. 99-SW-84-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. 99-SW-84-AD, 2601                           ( print page 25695)                        Meacham Blvd., Room 663, Fort Worth, Texas 76137.                 

## Discussion 

Transport Canada, which is the airworthiness authority for Canada, recently notified the FAA that an unsafe condition may exist on certain BHTC Model 430 helicopters. Transport Canada advises that a yaw control channel malfunctioned during a check for freedom-of-controls following maintenance because a screw that clamps the control arm to the yaw synchro resolver shaft was loose. This allowed the control arm to separate from the shaft and jam against an airframe stringer. To secure the installation of the four resolver control arms, the screws must be removed and replaced with airworthy screws and guard brackets must be installed. 

BHTC has issued Bell Helicopter Textron Alert Service Bulletin No. 430-99-11, dated May 7, 1999, which introduces a higher torque alloy steel screw to replace the screws for the yaw, roll, pitch, and collective syncro resolvers. This service bulletin also specifies installing a guard bracket on the yaw, roll, pitch, and collective syncro resolvers to prevent the control arm from separating in case of a loss of torque of the clamping screw. Transport Canada classified this service bulletin as mandatory and issued AD No. CF-99-26, dated September 28, 1999, in order to assure 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 section 21.29 of the Federal Aviation Regulations (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 the 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. 

Since an unsafe condition has been identified 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 replacing screws in the yaw, roll, pitch, and collective syncro resolvers, and installing a guard bracket on the yaw, roll, pitch, and collective syncro resolvers. The actions would be required to be accomplished in accordance with the service bulletins described previously. 

The FAA estimates that 33 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 6.0 work hours per helicopter to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Required parts would cost approximately $548. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $29,964. 

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.**

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Safety

## 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: 

# 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 

2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: 

**Bell Helicopter Textron Canada:**                                 Docket No. 99-SW-84-AD.                             

*Applicability:*                                 Model 430, serial numbers 49001 through 49018, 49020 through 49043, and 49045 through 49051, 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 (c) 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 within 150 hours time-in-service after the effective date of this AD, unless accomplished previously.                             

To prevent a jammed flight control and subsequent loss of control of the helicopter, accomplish the following: 

(a) Remove the arm clamp screws (screws) in the yaw, roll, pitch, and collective syncro resolvers and replace them with airworthy screws in accordance with the Accomplishment Instructions in Alert Service Bulletin 430-99-11, dated May 7, 1999 (ASB). 

(b) Install a guard bracket on the yaw, roll, pitch, and collective syncro resolvers in accordance with the Accomplishment Instructions in the ASB. 

(c) 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.

(d) Special flight permits may be issued in accordance with sections 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 No. CF-99-26, dated September 28, 1999.

Issued in Fort Worth, Texas, on April 20, 2000. 

Eric Bries, 

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. 

[FR Doc. 00-11063 Filed 5-2-00; 8:45 am] 

BILLING CODE 4910-13-U