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

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Information about this document as published in the Federal Register.

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Federal Aviation Administration, DOT.


Final rule.


This amendment supersedes an existing airworthiness directive (AD) that applies to Eurocopter Canada Ltd. Model BO 105 LS A-3 helicopters. That AD currently requires, before further flight, creating a component log card or equivalent record and determining the calendar age and number of flights on each tension-torsion (TT) strap, and inspecting and removing, as necessary, certain unairworthy TT straps. This amendment establishes a life limit for certain main rotor TT straps. This amendment is prompted by 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 the Model BO 105 LS A-3 helicopters. The actions specified by this AD are intended to prevent fatigue failure of a TT strap, loss of a blade, and subsequent loss of control of the helicopter.


October 19, 2000.

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Charles Harrison, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, Fort Worth, Texas 76193-0110, telephone (817) 222-5128, fax (817) 222-5961.

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A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 99-20-13, Amendment 39-11371 (64 FR 56156, October 18, 1999), which applies to Eurocopter Canada Ltd. Model BO 105 LS A-3 helicopters, was published in the Federal Register on June 19, 2000 (65 FR 37924). That action proposed to require establishing a life limit for the TT straps of 120 months or 25,000 flights, whichever occurs first.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

The FAA estimates that 20 helicopters of U.S. registry will be affected by this AD, that it will take approximately 16 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $10,400 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $227,200.

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

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List of Subjects in 14 CFR Part 39

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Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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 removing Amendment 39-11371 (

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2000-18-13 Eurocopter Canada Ltd.: Amendment 39-11899. Docket No. 99-SW-68-AD. Supersedes AD 99-20-13, Amendment 39-11371, Docket No. 99-SW-56-AD.

Applicability: Model BO 105 LS A-3 helicopters, with part number (P/N) 2604067 (Bendix) or J17322-1 (Lord) rotor tension torsion (TT) strap, 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 (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 fatigue failure of a TT strap, loss of a main rotor blade (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 TT strap. Enter both the age 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 time-in-service (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 or J17322-1, that has been in service 120 months since initial installation on any helicopter or accumulated 40,000 flights (a flight is a takeoff and a landing). Replace the TT strap with an airworthy TT strap.

(c) This AD revises the Airworthiness Limitations Section of the maintenance manual by establishing a life limit for the TT strap, P/N 2604067 and J17322-1, of 120 months or 40,000 flights, whichever occurs first.

(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, 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 §§ 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.

(f) This amendment becomes effective on October 19, 2000.

Note 3:

The subject of this AD is addressed in Transport Canada Civil Aviation, Canada, AD CF-99-24R1, dated September 22, 1999.

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Issued in Fort Worth, Texas, on September 5, 2000.

Henry A. Armstrong,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 00-23582 Filed 9-13-00; 8:45 am]