AD 97-01-06

This amendment adopts a new airworthiness directive (AD), applicable to Bell Helicopter Textron, Inc. (BHTI)-manufactured restricted category Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters, that requires a one-time inspection of the tail rotor slider (slider) to verify that it was manufactured with the correct outside diameter. This amendment is prompted by a United States (U.S.) Army Safety of Flight message that reports that some sliders may have been improperly manufactured with an undersized wall thickness by U.S. Army vendors. The actions specified by this AD are intended to prevent fatigue failure of the slider, which could cause loss of tail rotor control and subsequent loss of control of the helicopter.

Final rule

97-01-06 CALIFORNIA DEPARTMENT OF FORESTRY; ERICKSON AIR CRANE CO.; GARLICK HELICOPTERS; HAWKINS AND POWERS AVIATION, INC.; INTERNATIONAL HELICOPTERS, INC.; SMITH HELICOPTERS; SOUTHWEST FLORIDA AVIATION; WEST COAST FABRICATIONS; WESTERN INTERNATIONAL AVIATION, INC.; WILLIAMS HELICOPTER TECHNOLOGY, INC.; AND UNC HELICOPTERS: Amendment 39-9877. Docket No. 96-SW-03-AD.

Applicability: Bell Helicopter Textron, Inc.-manufactured Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters, certificated in the restricted category.

NOTE 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been 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 use the authority provided in paragraph (b) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any helicopter from the applicability of this AD.

Compliance: Required within 5 hours time-in-service after the effective date of this AD, unless accomplished previously.

To prevent fatigue failure of the tail rotor slider (slider), which could cause loss of the tail rotor and subsequent loss of control of the helicopter, accomplish the following:

(a) Using a calibrated caliper or micrometer, measure the outside diameter of the splined shaft (barrel) of the slider, part number (P/N) 204-010-720-3 or P/N 204-010-720-003, at two points that are 90 degreesapart on the outside circumference of the barrel, one-half to one inch from either end of the slider. If the outside diameter of the slider is less than 1.300 inches, remove the slider and replace it, prior to further flight, with a slider that has an outside diameter of 1.300 inches or greater.

(b) 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Certification Office.

(c) Special flight permits may be issued in accordance with sections 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.

(d) This amendment becomes effective on February 13, 1997.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to Bell Helicopter Textron, Inc. (BHTI)-manufactured restricted category Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters was published in the Federal Register on September 5, 1996 (61 FR 46742). That action proposed to require a one-time inspection of the tail rotor slider (slider) to verify that it was manufactured with the correct outside diameter.

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, with one exception. The word "barrel" was added to paragraph (a) of the AD to indicate that the splined shaft of the slider is also known as the barrel of the slider. This change neither increases the costs associated with the AD nor increases the scope of the AD.

The FAA estimates that 80 helicopters of U.S. registry will be affected by this AD, that it will take approximately 0.5 work hour per helicopter to accomplish the required inspection, and that the average labor rate is $60 per work hour. Replacement of the slider requires 8 hours, and required parts cost approximately $72 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $46,560 if replacement of the slider is required in all of the fleet.

The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined thatthis final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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 location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.

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:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 USC 106(g), 40113, 44701.

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