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Proposed Rule

Airworthiness Directives; Bell Helicopter Textron Canada Model 407 Helicopters

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Federal Aviation Administration, DOT.


Notice of proposed rulemaking (NPRM).


This document proposes adopting a new airworthiness directive (AD) for Bell Helicopter Textron Canada (Bell) Model 407 helicopters. This proposal would require creating a component history card or equivalent record for each crosstube assembly, Start Printed Page 47042converting accumulated run-on landings to an accumulated Retirement Index Number (RIN) count, and establishing a maximum accumulated RIN for certain crosstube assemblies. This proposal is prompted by fatigue testing, analysis, and evaluation by the manufacturer that determined that run-on landings impose a high stress on landing gear or crosstubes and may cause cracking in the area above the skid tube saddle. The actions specified by this proposed AD are intended to prevent fatigue failure in a crosstube assembly due to excessive stress during run-on landings and subsequent loss of control of the helicopter.


Comments must be received on or before October 4, 2004.


Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2004-SW-07-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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Sharon Miles, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations and Policy Group, Fort Worth, Texas 76193-0111, telephone (817) 222-5122, 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 will be considered before taking action on the proposed rule. The proposals contained in this document 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 proposal must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2004-SW-07-AD.” The postcard will be date stamped and returned to the commenter.


Transport Canada, the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on Bell Model 407 helicopters. Transport Canada advises that run-on landings impose high stress on landing gear crosstubes, and to prevent possible crosstube failure, the manufacturer has introduced the life limitation of 5,000 RIN. Further evaluation has confirmed the possibility that an extensive training environment with run-on landings may impose high stress on crosstubes. The same condition may result from repetitive landings with forward travel with rotorcraft weight on the skids.

Bell has issued Alert Service Bulletin No. 407-03-59, dated October 15, 2003, which specifies assigning a RIN count to forward and aft crosstube assemblies on Model 407 helicopters. Transport Canada classified this alert service bulletin as mandatory and issued AD No. CF-2004-03, dated February 11, 2004, 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 agreement. Pursuant to the applicable bilateral 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.

This previously described unsafe condition is likely to exist or develop on other helicopters of the same type design registered in the United States. Therefore, the proposed AD would require, before further flight, creating a component history card or equivalent record for each crosstube assembly, converting accumulated run-on landings to an accumulated RIN count, and establishing a retirement life of 5,000 accumulated RIN for the affected crosstube assemblies.

The FAA estimates that 319 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 4 work hours per helicopter to replace the forward and aft crosstube assemblies, and that the average labor rate is $65 per work hour. Required parts would cost approximately $6,670 per helicopter for both forward and aft low gear crosstube assemblies or $8,450 per helicopter for both forward and aft high gear crosstube assemblies. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $2,210,670 to replace the low gear crosstube assemblies on the entire fleet or $2,778,490 to replace the high-gear crosstube assemblies on the entire fleet and assuming the costs associated with creating and updating the historical component card are negligible.

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 economic 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 (Bell): Docket No. 2004-SW-07-AD.

Applicability: Model 407 helicopters, with landing gear crosstube assemblies, part number (P/N) 407-050-101-101 and -103; P/N 407-050-102-101 and -103; P/N 407-050-201-101 and -103; P/N 407-050-202-101 and -103; P/N 407-704-007-119; P/N 407-722-101; P/N 407-723-104; P/N 407-724-101; or P/N 407-725-104, installed, certificated in any category.

Note 1:

This AD applicability includes both Bell crosstube assemblies and Bell's approved production and spare alternate crosstube assemblies from Aeronautical Accessories Incorporated (AAI).

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue failure of the crosstube assembly and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight, create a component history card or equivalent record for each crosstube assembly.

(b) Before further flight, determine and record the accumulated Retirement Index Number (RIN) for each crosstube assembly as follows:

(1) For each crosstube assembly, record one (1) RIN for every run-on landing.

(2) For any crosstube assembly with an unknown number of run-on landings, assume and record ten (10) RINs for each 100 hours TIS since the crosstube assembly was installed (for example, 5,000 hours of time-in-service equals 500 RIN).

(c) Replace any crosstube assembly on or before reaching 5,000 RIN.

Note 2:

Bell Helicopter Textron Alert Service Bulletin No. 407-03-59, dated October 15, 2003, pertains to the subject of this AD.

(d) This AD revises the Airworthiness Limitations section of the maintenance manual by establishing a retirement life of 5,000 RIN for the affected crosstube assemblies.

(e) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Regulations and Policy Group, Rotorcraft Directorate, FAA, for information about previously approved alternative methods of compliance.

Note 3:

The subject of this AD is addressed in Transport Canada (Canada) AD No. CF-2004-03, dated February 11, 2004.

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Issued in Fort Worth, Texas, on July 28, 2004.

David A. Downey,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 04-17795 Filed 8-3-04; 8:45 am]