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Proposed Rule

Airworthiness Directives; Bell Helicopter Textron, Inc., Model 412 Helicopters

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AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes adopting a new airworthiness directive (AD) for Bell Helicopter Textron, Inc. (BHTI) Model 412 helicopters. The AD would require, within 25 hours time-in-service (TIS), reviewing the aircraft maintenance records and determining the number of landings for the high landing gear aft crosstube assembly (crosstube assembly); inspecting the crosstube assembly for damage; and replacing any unairworthy crosstube assembly. Additionally, the AD would require creating a component history card or equivalent record, and establishing a retirement life for each crosstube assembly. This AD would also require vibro-etching a part number (P/N) and serial number (S/N) on certain cross tube assemblies. This proposal is prompted by reported field failures of crosstube assemblies. The actions specified by the proposed AD are intended to detect damage that could lead to a fatigue crack in the crosstube assembly, failure of the crosstube assembly, and subsequent loss of control of the helicopter during landing.

DATES:

Comments must be received on or before January 16, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2000-SW-60-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 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

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FOR FURTHER INFORMATION CONTACT:

Michael Kohner, Aviation Safety Engineer, Rotorcraft Certification Office, Rotorcraft Directorate, FAA, Fort Worth, Texas 76193-0170, telephone (817) 222-5447, fax (817) 222-5783.

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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 will be considered before taking action on the proposed rule. The proposals contained in this action 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 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 action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2000-SW-60-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-60-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

This document proposes adopting a new AD for BHTI Model 412 helicopters. This proposal would require the following within 25 hours TIS:

  • Reviewing the aircraft maintenance records and determining the number of landings for the crosstube assembly;
  • Inspecting the crosstube assembly for damage and replacing any unairworthy crosstube assembly;
  • Vibro-etching a P/N on certain crosstube assemblies;
  • Vibro-etching a S/N on the crosstube assemblies;
  • Creating a component history card or equivalent record for the crosstube assembly; and
  • Revising the Airworthiness Limitations section of the maintenance manual by establishing a retirement life of 10,000 landings for crosstube assemblies, P/N 412-050-010-101 and 412-050-011-107 FM, and a retirement life of 20,000 landings for crosstube assemblies, P/N 412-050-045-107.

This proposal is prompted by reports of field failures of crosstube assemblies. Analysis of the failures indicates that a landing life limit must be assigned to the crosstube assembly. The actions specified by the proposed AD are intended to detect damage that could lead to a fatigue crack in the crosstube assembly, failure of the crosstube assembly, and subsequent loss of control of the helicopter during landing.

The FAA has reviewed BHTI Service Bulletin No. 412-99-97, dated January 8, 1999 (ASB), which describes procedures for verifying that the affected crosstube assemblies meet inspection criteria, assigning a retirement life on the affected crosstube assemblies; vibro-etching a P/N on those crosstube assemblies not displaying a visible P/N; vibro-etching a S/N on the affected crosstube assemblies, and providing information for calculating the number of landings.

We have identified an unsafe condition that is likely to exist or develop on other BHTI Model 412 helicopters of the same type design. The proposed AD would require, within 25 hours TIS, for affected crosstube assemblies, reviewing the aircraft maintenance records and determining the number of landings for the crosstube assembly; inspecting the crosstube assembly; replacing any unairworthy crosstube assembly with an airworthy crosstube assembly; vibro-etching the S/N on the crosstube assembly; creating Start Printed Page 68954a component history card or equivalent record; and establishing a retirement life. The AD would also require, on certain crosstube assemblies, vibro-etching a P/N.

The FAA estimates that 138 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 5 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 $6,044 for crosstube assembly, P/N 412-050-010-101, and $11,415 for crosstube assembly, P/N 412-050-045-107. BHTI states in the ASB that customers with affected crosstube assemblies are eligible for a special rebate credit ranging from 25 percent of the replacement cost to 100 percent depending on the age of the crosstube assembly. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $875,472 to replace all crosstube assemblies with crosstube assembly, P/N 412-050-010-101, or $1,616,670 to replace all crosstube assemblies with crosstube assembly, P/N 412-050-045-107. The total costs would be $41,400 for labor if all of the crosstube assemblies were replaced with 100 percent parts credit.

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

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The Proposed Amendment

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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 (

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PART 39—AIRWORTHINESS DIRECTIVES

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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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[Amended]

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

Bell Helicopter TEXTRON, Inc.: Docket No. 2000-SW-60-AD.

Applicability: Model 412 helicopters with high landing gear aft crosstube assembly (crosstube assembly), part number (P/N) 412-050-010-101, 412-050-011-107 FM, or 412-050-045-107, installed, 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 (e) 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.

Note 2:

Bell Helicopter Textron, Inc. Alert Service Bulletin 412-99-97, dated January 8, 1999, pertains to the subject of this AD.

To prevent a fatigue crack in the crosstube assembly, failure of the crosstube assembly, and subsequent loss of control of the helicopter during landing, accomplish the following:

(a) Within 25 hours time-in-service (TIS) and thereafter before installing a replacement crosstube assembly:

(1) Review the aircraft maintenance records and determine the number of landings for the crosstube assembly. Operators who do not have landing records may determine the number of landings by multiplying the hours TIS of the crosstube assembly by a factor of 4. If the number of hours TIS of the crosstube assembly is unknown, within 30 days, remove the crosstube assembly from service and replace it with an airworthy crosstube assembly.

(2) Inspect the crosstube assembly for damage. If damage exceeds the maximum allowable damage limits and repair criteria, as specified in the applicable maintenance manual, before further flight, replace it with an airworthy crosstube assembly.

(3) Vibro-etch the P/N on the crosstube assembly adjacent to the skid tube saddle in accordance with Figure 1 for any crosstube assembly not displaying a visible P/N. Identify the crosstube assembly as P/N 412-050-011-107 FM.

(4) Vibro-etch a serial number (S/N) on the crosstube assembly below the P/N in accordance with Figure 1. The S/N must be unique for each crosstube assembly.

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(5) Create a component history card or equivalent record for each crosstube assembly and enter the P/N, S/N, and the accumulated number of landings derived in accordance with paragraph (1).

(6) Begin tracking the number of landings for each crosstube assembly on the component history card or equivalent record.

(b) For a crosstube assembly, P/N 412-050-010-101 or 412-050-011-107 FM, on or before accumulating 10,000 landings or within 25 hours TIS after the effective date of this AD, whichever occurs later, replace the crosstube assembly with an airworthy crosstube assembly.

(c) For a crosstube assembly, P/N 412-050-045-107, on or before accumulating 20,000 landings or within 25 hours TIS after the effective date of this AD, whichever occurs later, replace the crosstube assembly with an airworthy crosstube assembly.

(d) This AD revises the Airworthiness Limitations section of the Maintenance Manual by establishing a life limit of 10,000 landings for the crosstube assembly, P/N 412-050-010-101 and 412-050-011-107 FM, and 20,000 landings for the crosstube assembly, P/N 412-050-045-107.

(e) 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, Rotorcraft Certification Office, 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, Rotorcraft Certification Office.

Note 3:

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

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

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Issued in Fort Worth, Texas, on November 8, 2000.

Henry A. Armstrong,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 00-29211 Filed 11-14-00; 8:45 am]

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