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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 99-SW-42-AD] 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Notice of proposed rulemaking (NPRM). 

# SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD) applicable to BHTC Model 430 helicopters. That AD requires inspecting all four main rotor adapter assemblies for evidence of flapping and lead-lag contact. That AD also requires installing a never-exceed-velocity (VNE) placard with markings on the airspeed indicator glass and instrument case and a revision to the rotorcraft flight manual (RFM) to reflect the airspeed revision. This action would provide mandatory terminating action for requirements of that AD by replacing the fluidlastic damper blade sets with improved sets that incorporate a pressure indicator to detect loss of damper fluid. This proposal is prompted by the need for a positive means of detecting loss of damper fluid that could result in main rotor tip path plane separation. The actions specified by the proposed AD are intended to prevent increased vibrations, damage to the main rotor system, and subsequent loss of control of the helicopter. 

# DATES:

Comments must be received on or before July 10, 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-42-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 this location 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, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham Blvd., Fort Worth, Texas 76137, 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 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. 99-SW-42-AD.” The postcard will be date stamped and returned to the commenter.                           ( print page 26784)    

## 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-42-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. 

## Discussion 

On September 26, 1997, the FAA issued AD No. 97-15-16, Amendment 39-10152 (62 FR 52653, October 9, 1997). That AD requires inspecting the BHTC Model 430 helicopter main rotor adapter assemblies for evidence of flapping and lead-lag contact. That AD also requires installing a VNE placard, with markings to reflect the airspeed restriction, and inserting revisions to the RFM to reflect the airspeed revisions. That action was prompted by a report of a main rotor tip path plane separation, which occurred during a ferry flight at airspeed of more than 140 knots indicated airspeed. The requirements of that AD are intended to prevent tip path plane separation, increased vibrations, damage to the main rotor system, and subsequent loss of control of the helicopter. 

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 a main rotor tip path plane separation on a Model 430 helicopter was caused by the limited damping characteristics of the elastomeric lead-lag dampers. 

Since the issuance of AD 97-15-16, BHTC has issued Alert Service Bulletin (ASB) 430-97-4, dated December 14, 1997, and ASB 430-98-8, dated December 31, 1998, that provide for replacing the fluidlastic damper blade sets with improved sets, part number (P/N) 430-310-104-105. The improved fluidlastic damper blade sets incorporate a pressure indicator to provide a positive means of leak detection, thereby replacing the requirements of ASB 430-97-2, dated July 11, 1997, and ASB 430-97-4, dated December 19, 1997. 

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, the proposed AD would maintain the same requirements as AD 97-15-16 until an improved fluidlastic damper blade set, P/N 430-310-104-105, is installed that incorporates a pressure indicator to detect loss of damper fluid. 

The FAA estimates that 7 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 11 work hours per helicopter to accomplish the proposed actions, and that the average labor rate is $60 per work hour. The required parts would cost approximately $122,945 per set of 4. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $865,235 to replace the damper blade sets in the entire fleet. 

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 removing Amendment 39-10152 (62 FR 52653, October 9, 1997), and by adding a new airworthiness directive (AD), to read as follows: 

**Bell Helicopter Textron Canada:**                                 Docket No. 99-SW-42-AD. Supersedes AD 97-15-16, Amendment 39-10152, Docket 97-SW-24-AD.                             

*Applicability:*                                 Model 430 helicopters, 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 (d) 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 as indicated, unless accomplished previously.                             

To prevent tip path plane separation, increased vibrations, damage to the main rotor system, and subsequent loss of control of the helicopter, accomplish the following: 

(a) Before further flight: 

(1) Inspect all four main rotor adapter assemblies for flapping contact between the adapter liners and the upper stop assembly plugs. Refer to Figures 1, 2, and 3 of the Accomplishment Instructions of Bell Helicopter Textron Canada (BHTC) Alert Service Bulletin (ASB) No. 430-97-2, dated July 11, 1997. Flapping contact is indicated by the scrubbing (or smudging) of the adapter liner surface, characteristic of relative motion between the surfaces of the adapter lines and upper stop assembly plugs. 

(2) Inspect all four main rotor adapter assemblies for lead-lag contact between the adapter pads and the yoke assembly. Refer to Figures 1 and 2 of the Accomplishment Instructions of BHTC ASB No. 430-97-2, dated July 11, 1997. Lead-lag contact is indicated by a permanent indentation or split in the surface of the adapter pads. 

(3) If the inspections in paragraphs (a)(1) or (a)(2) of this AD reveal that there has been contact, inspect and replace the main rotor yoke and stop assemblies in accordance with Part I, No. 3 of the Accomplishment Instructions of BHTC ASB No. 430-97-2, dated July 11, 1997, except return of any damaged upper stops to the manufacturer is not required. 

(4) For helicopters with skid landing gear or retractable landing gear, remove the existing never-exceed-velocity (VNE) placard from the overhead console and install VNE placard, P/N 430-075-208-107, or P/N 430-075-208-109, as applicable, in accordance with Part II, of the Accomplishment Instructions of BHTC ASB No. 430-97-2, dated July 11, 1997. 

(5) Install on each airspeed indicator a red arc between 120 knots and 150 knots to indicate that airspeeds above 120 knots indicated airspeed are prohibited. Install a slippage mark on each airspeed indicator glass and instrument case. 

(6) Insert the temporary revisions, BHT-430-FM-1 and BHT-430-FMS-1, as appropriate, both dated July 7, 1997, into the rotorcraft flight manual. 

                                (b) Within 100 hours time-in-service, (1) Remove the fluidlastic damper blade set, P/N 430-310-100-101 or 430-310-107-101 in accordance with the Accomplishment                                       ( print page 26785)                                    Instructions of ASB 430-97-4, dated December 19, 1997, Part 1, steps 1 through 5, and install damper blade set, P/N 430-310-104-105, in accordance with the Accomplishment Instructions, Part I, of BHTC ASB 430-98-8, dated December 31, 1998.                             

(2) Return pilot and copilot airspeed indicators to their original configuration by removing the markings specified by paragraph (a)(5) of this AD. 

(3) Remove the temporary revisions, BHT 430-FM-1 or BHT-430-FMS-1, as appropriate, both dated July 7, 1997. Insert the temporary revisions, BHT-430-FM-1, or BHT-430-FMS-1, as appropriate, both dated December 11, 1998, into the rotorcraft flight manual. 

(c) If paragraph (b)(1) was previously accomplished by installation of fluidlastic damper blade set, P/N 430-310-104-103, remove fluidlastic damper blade set, P/N 430-310-104-103, and install fluidlastic damper blade set, P/N 430-310-104-105, in accordance with the Accomplishment Instructions of BHTC ASB 430-98-8, dated December 31, 1998. 

(d) 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, FAA, 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.

(e) 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-97-23R1, dated March 30, 1999.

Issued in Fort Worth, Texas, on April 28, 2000. 

Eric Bries, 

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. 

[FR Doc. 00-11522 Filed 5-8-00; 8:45 am] 

BILLING CODE 4910-13-P