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Proposed Rule

Airworthiness Directives; Eurocopter Canada Limited Model BO 105 LS A-3 Helicopters

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Federal Aviation Administration, DOT.


Notice of proposed rulemaking (NPRM).


This document proposes adopting a new airworthiness directive (AD) for Eurocopter Canada Limited (Eurocopter) Model BO 105 LS A-3 helicopters. This proposal would require replacing certain fixed bolts and nuts, reidentifying certain main rotor nuts, and revising the Airworthiness Limitations—Time Change Items (TCI) list to reflect the new life limits and new part numbers. This proposal is prompted by a re-evaluation of certain fatigue-critical parts, which resulted in establishing new life limits for certain like-numbered parts and reidentifying a certain existing part with a different part number, or in some cases, replacing them with new parts. The actions specified by this proposed AD are intended to prevent fatigue failure of the fixed bolts and nuts, and subsequent loss of control of the helicopter.


Comments must be received on or before July 3, 2006.


Use one of the following addresses to submit comments on this proposed AD:

  • DOT Docket Web site: Go to and follow the instructions for sending your comments electronically;
  • Government-wide rulemaking Web site: Go to Start Printed Page 25788and follow the instructions for sending your comments electronically;
  • Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590;
  • Fax: 202-493-2251; or
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

You may get the service information identified in this proposed AD from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527.

You may examine the comments to this proposed AD in the AD docket on the Internet at

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

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Comments Invited

We invite you to submit any written data, views, or arguments regarding this proposed AD. Send your comments to the address listed under the caption ADDRESSES. Include the docket number “FAA-2006-24632, Directorate Identifier 2005-SW-31-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed rulemaking. Using the search function of our docket Web site, you can find and read the comments to any of our dockets, including the name of the individual who sent or signed the comment. You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit

Examining the Docket

You may examine the docket that contains the proposed AD, any comments, and other information in person at the Docket Management System (DMS) Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone 1-800-647-5227) is located at the plaza level of the Department of Transportation Nassif Building in Room PL-401 at 400 Seventh Street, SW., Washington, DC. Comments will be available in the AD docket shortly after the DMS receives them.


Transport Canada, the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on Eurocopter Model BO 105 LS A-3 helicopters. Transport Canada advises that changes to the TCI list must be incorporated, and affected parts must be replaced and reidentified in accordance with the manufacturer's service information.

Eurocopter has issued Alert Service Bulletin No. ASB BO 105 LS 10-11, dated May 11, 2005, which specifies changes to and introduction of life limits, and reidentification of certain life-limited parts. Transport Canada classified this alert service bulletin as mandatory and issued AD No. CF-2005-17, dated June 6, 2005, 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 us informed of the situation described above. We have 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.

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, within 30 days, incorporating revised life limits and part numbers into the list of life-limited parts, or TCI list, which is contained in the helicopter delivery file, and within 150 hours time-in-service (TIS), replacing 4 fixed bolts, part number (P/N) LN 9038 K08018, with fixed bolts, P/N 105-101021.17. It would also require replacing 4 main rotor nuts, P/N 105-142241.01, within 30 days if they have less than 150 hours TIS remaining, or reidentifying those main rotor nuts within 150 hours TIS if they have 150 or more hours TIS remaining. The actions would be required to be accomplished by following specified portions of the alert service bulletin described previously.

We estimate that this proposed AD would affect 7 helicopters of U.S. registry and the proposed actions would take approximately:

  • 1 work hour per helicopter to remove and replace 4 fixed bolts;
  • 16 work hours per helicopter to remove, replace, and reidentify four nuts; and
  • 1 work hour per helicopter to create component history cards at an average labor rate of $65 per work hour. Required parts would cost approximately $3.80 for each fixed bolt, P/N 105-101021.17, and $882.67 for each nut, P/N 105-142241.01. Based on these figures, we estimate the total cost impact of the proposed AD on U.S. operators to be $33,011, assuming all nuts and bolts on the entire fleet are replaced.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. Additionally, this proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a draft economic evaluation of the estimated costs to comply with this proposed AD. See the DMS to examine the draft economic evaluation.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in Start Printed Page 25789air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

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List of Subjects in 14 CFR Part 39

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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:

Eurocopter Canada Limited: Docket No. FAA-2006-24632; Directorate Identifier 2005-SW-31-AD.

Applicability: Model BO 105 LS A-3 helicopters, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue failure of a fixed bolt and main rotor nut, and subsequent loss of control of the helicopter, accomplish the following:

(a) Within 30 days:

(1) Modify the Airworthiness Limitation section, Time Change Items (TCI) list, or table of life-limited components, with their revised life limits by adding part number (P/N) 105-142241.01 and by changing P/N LN 9038 K08018 to P/N 105-101021.17, as shown in the following table.

Part nameP/NLife limit
Fixed Bolt (Bolt)105-101021.17 (Formerly P/N LN 9038-K08018)6,000 hours time-in-service (TIS).
Main Rotor Nut (Nut)105-142241.01122,850 flights or 18,900 hours TIS, whichever occurs first.
The number of flights equals the number of landings (i.e., ground contacts).

(2) Create a historical or equivalent record for each of the parts listed in the preceding table.

(3) Review the aircraft records and determine the TIS and landings on each nut, P/N 105-142241.01. If the number of flights (i.e., landings) is unknown, the initial life limit is 18,900 hours TIS. Thereafter, record the number of flights for use when determining the retirement life.

(b) Before further flight, replace any nut that has less than 150 hours TIS remaining before reaching its life limit. Unless accomplished previously, prior to replacing a nut, reidentify the nut in accordance with paragraph (c)(2) of this AD.

(c) Within 150 hours TIS:

(1) Replace the 4 bolts, P/N LN 9038 K08018, with bolts, P/N 105-101021.17, as shown in Figure 1 of Eurocopter Alert Service Bulletin No. ASB BO 105 LS 10-11, dated May 11, 2005 (ASB).

(2) For those nuts with 150 or more hours TIS remaining on their life, remove and reidentify those nuts, P/N 105-142241.01, by adding the serial number of the main rotor head, followed by a dash and a consecutive number, in accordance with the procedures stated in Figure 2 of the ASB.

(d) Before further flight, remove any life-limited part on which the life limit has been equaled or exceeded.

(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 Manager, Regulations and Policy Group, Rotorcraft Directorate, FAA, ATTN: Sharon Miles, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations and Guidance Group, Fort Worth, Texas 76193-0111, telephone (817) 222-5122, fax (817) 222-5961, for information about previously approved alternative methods of compliance.


The subject of this AD is addressed in Transport Canada (Canada) AD No. CF-2005-17, dated June 6, 2005.

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Issued in Fort Worth, Texas, on April 24, 2006.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. E6-6589 Filed 5-1-06; 8:45 am]