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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2011-0596; Directorate Identifier 2008-SW-37-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration, DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

                        This document proposes superseding an existing airworthiness directive (AD) for Eurocopter Canada                               ( print page 52594)                            Ltd. Model BO 105 LS A-3 helicopters. That AD currently requires establishing a life limit for certain tension-torsion (TT) straps. This action would require reducing the “number of flights” life limit and providing a time-in-service (TIS) life limit for those TT straps. This proposal is prompted by a recalculation by the manufacturer and subsequent changes to the service information related to the retirement time of the TT strap initially adopted as a result of an accident in which a main rotor blade (blade) separated from a Eurocopter Deutschland GMBH (ECD) Model MBB-BK 117 helicopter due to fatigue failure of a TT strap. The same part-numbered TT strap is used on Model BO 105 LS A-3 helicopters. The actions specified by the proposed AD are intended to prevent fatigue failure of a TT strap, loss of a blade, and subsequent loss of control of the helicopter.                    

# DATES:

Comments must be received on or before October 24, 2011.

# ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:
      -  Federal eRulemaking Portal:                          Go to                          http://www.regulations.gov . Follow the instructions for submitting comments.                    
      -  Fax:                          (202) 493-2251.                    
      -  Mail:                          U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.                    
      -  Hand Delivery:                          U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, 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, TX 75053-4005, telephone (972) 641-3460, fax (972) 641-3527, or at                         *http://www.eurocopter.com*.                    

# FOR FURTHER INFORMATION CONTACT:

Sharon Miles, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations and Policy Group, 2601 Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5122, fax (817) 222-5961.

# SUPPLEMENTARY INFORMATION:

## Comments Invited

                    We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the caption                     **ADDRESSES**                    . Include the “Docket No. FAA-2011-0596; Directorate Identifier 2008-SW-37-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 because of those comments.                

                    We will post all comments we receive, without change, to                     *http://www.regulations.gov,*                     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 the 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).                

## Examining the Docket

                    You may examine the docket that contains the proposed AD, any comments, and other information on the Internet at                     *http://www.regulations.gov*                     or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone (800) 647-5527) is located in Room W12-140 on the ground floor of the West Building at the street address stated in the                     **ADDRESSES**                     section. Comments will be available in the AD docket shortly after receipt.                

## Discussion

On September 5, 2000, we issued superseding AD 2000-18-13, Amendment 39-11899 (65 FR 55452, September 14, 2000), to establish a life limit for TT strap, part number (P/N) 2604067 (Bendix) or P/N J17322-1 (Lord), of 120 months or 40,000 flights, whichever occurs first. That action was prompted by an accident in July 1999 in which a blade separated from a Eurocopter Deutschland GMBH (ECD) Model MBB-BK 117 helicopter due to fatigue failure of a TT strap. The same part-numbered TT strap is also used on the Eurocopter Canada Ltd. Model BO 105 LS A-3 helicopters. The requirements of that AD are intended to prevent failure of a TT strap, loss of a blade, and subsequent loss of control of the helicopter.

Since issuing that AD, the manufacturer has recalculated the retirement time, provided a time-in-service (TIS) limit, and issued revised service information related to the life limit of the TT strap.

Transport Canada, which is the aviation authority for Canada, has issued Canadian AD No. CF-2008-17R1, dated May 26, 2008, to correct an unsafe condition for the Eurocopter Canada Ltd. (formerly MBB Canada Ltd.) Model BO 105-LS-A3 helicopters. Transport Canada advises that “the tension-torsion strap (TTS) failure on a MBB BK 117 helicopter in July 1999, initiated a TTS service life recalculation. This recalculation changed the retirement time in Chapter 4 of Maintenance Manual. As a result of this change, the TTS in service are to be replaced or inspected as a precautionary measure, pending already accumulated service hours and the calendar time since their last installation.”

Since the issuance of the Transport Canada AD, the type certificate for this helicopter model has been transferred to the Federal Republic of Germany. The European Aviation Safety Agency (EASA), which is the Technical Agent for the Federal Republic of Germany, has adopted Transport Canada AD No. CF-2008-17R1, dated May 26, 2008, and requires compliance with that AD.

## Related Service Information

Eurocopter Canada Limited issued Alert Service Bulletin No. ASB-BO 105 LS-10-10, Revision 1, dated January 8, 2008 (ASB). The ASB describes procedures for determining the total accumulated installation time and factoring the number of flights on each TT strap. The ASB also describes and contains a graph for determining the revised life limit, and provides various compliance intervals, inspection provisions, and replacement criteria for the TT strap. The previously described ASB specifies procedures for determining the total accumulated installation time and number of flights on TT strap, P/N 2604067 (Bendix) or P/N J17322-1 (Lord). The ASB also describes establishing a revised life limit for the TT strap of 120 months, 25,000 flights, or 3,800 hours, whichever occurs first. Transport Canada classified this alert service bulletin as mandatory and issued AD No. CF-2008-17R1, dated May 26, 2008, to ensure the continued airworthiness of these helicopters. EASA, the Technical Agent for the current type certificate holder, the Federal Republic of Germany, has adopted and requires compliance with Transport Canada AD No. CF-2008-17R1, dated May 26, 2008.

## FAA's Evaluation and Unsafe Condition Determination

                    This helicopter has been approved by the aviation authority of the Federal Republic of Germany and is approved for operation in the United States. Pursuant to our bilateral agreement with                           ( print page 52595)                        the Federal Republic of Germany, EASA, their technical representative, has notified us of the unsafe condition described in the Transport Canada AD, which has been adopted by EASA. We are proposing this AD because we evaluated all information provided by EASA and Transport Canada and determined the unsafe condition exists and is likely to exist or develop on other helicopters of the same type design. This proposed AD would require establishing a revised life limit for TT strap, P/N 2604067 (Bendix) or P/N J17322-1 (Lord), of 120 months, 25,000 flights, or 3,800 hours time-in-service (TIS), whichever occurs first.                

## Differences Between This Proposed AD and the Transport Canada AD

Our AD differs from the Transport Canada AD as follows:
    - The Transport Canada AD uses the terms “air time hours” and “flight hours” to describe compliance times, and this proposed AD uses the term “hours time-in-service”.
    - The Transport Canada AD requires inspections for tension-torsion straps that have an accumulated installation time of 10 or more years, and our AD does not require these inspections.
    - The Transport Canada AD requires verifying and establishing a new service life for the tension-torsion straps within the next 25 hours TIS, and this AD requires this to be done before further flight.

## Costs of Compliance

We estimate that this proposed AD would affect 13 helicopters of U.S. registry and the proposed actions would take about 15 work hours per helicopter to accomplish at an average labor rate of $85 per work hour. Required parts would cost about $13,867 per helicopter. Based on these figures, we estimate the total cost impact of the proposed AD on U.S. operators to be $196,846 to replace all the affected TT straps in the entire fleet.

## 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);

3. Will not affect intrastate aviation in Alaska to the extent that it justifies making a regulatory distinction; and

4. 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 an economic evaluation of the estimated costs to comply with this proposed AD. See the AD docket to examine the 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 air 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.

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Safety

## The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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 39-11899 (65 FR 55452; September 14, 2000), and adding the following new airworthiness directive (AD):

**EUROCOPTER CANADA LTD.:**                                 Docket No. FAA-2011-0596; Directorate Identifier 2008-SW-37-AD. Supersedes AD 2000-18-13; Amendment 39-11899; Docket No. 99-SW-68-AD.                            

*Applicability:*                                 Model BO 105 LS A-3 helicopters, with tension-torsion (TT) strap, part number (P/N) 2604067 (Bendix) or J17322-1 (Lord), installed, certificated in any category.                            

*Compliance:*                                 Required as indicated, unless accomplished previously.                            

To prevent fatigue failure of a TT strap, loss of a main rotor blade, and subsequent loss of control of the helicopter accomplish the following:

(a) Before further flight:

(1) Create a component log card or equivalent record for each TT strap.

(2) Review the history of each helicopter and TT strap. Determine the age since initial installation on any helicopter (age) and the number of flights on each affected TT strap. Enter the age, hours time-in-service (TIS), and the number of flights for each TT strap on the component log card or equivalent record. When the number of flights is unknown, multiply the number of hours TIS by 5 to determine the number of flights. If a TT strap has been previously used at any time on Model BO-105LS A-3 ‘SUPER LIFTER”, BO-105 CB-5, BO-105 CBS-5, BO-105 DBS-5, or any MBB-BK 117 series helicopter, multiply the total number of flights accumulated on those other models by a factor of 1.6 and then add that result to the number of flights accumulated on the helicopters affected by this AD.

(3) Remove any TT strap from service if the total hours TIS or number of flights and age cannot be determined.

(b) Remove any TT strap, P/N 2604067 (Bendix) or P/N J17322-1 (Lord), that has been in service for 120 months since initial installation on any helicopter, or has accumulated 25,000 flights (a flight is a takeoff and a landing), or has been in service for 3,800 hours TIS.

(c) This AD revises the Airworthiness Limitations Section of the maintenance manual by establishing a revised life limit for the TT strap, P/N 2604067 (Bendix) or P/N J17322-1 (Lord), of 120 months, 25,000 flights, or 3,800 hours TIS, whichever occurs first.

# Note 1:

 Eurocopter Canada Limited Alert Service Bulletin No. ASB-BO 105 LS-10-10, Revision 1, dated January 8, 2008, which is not incorporated by reference, contains additional information about the subject of this AD.

(d) 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, Safety Management Group, FAA, ATTN: Sharon Miles, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations and Policy Group, 2601 Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5122, fax (817) 222-5961, for information about previously approved alternative methods of compliance.

(e) The Joint Aircraft System/Component (JASC) Code is 6200: Main Rotor System.

# Note 2:

                                     The subject of this AD is addressed in Transport Canada (Canada) AD No. CF-2008-17R1, dated May 26, 2008. The European Aviation Safety Agency, which is the Technical Agent for the current type certificate holder, the Federal Republic of                                           ( print page 52596)                                        Germany, has adopted and requires compliance with the Transport Canada AD.                                

Issued in Fort Worth, Texas, on June 3, 2011.

Kim Smith,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 2011-21472 Filed 8-22-11; 8:45 am]

BILLING CODE 4910-13-P