AD 98-07-09

This amendment adopts a new airworthiness directive (AD), applicable to Bell Helicopter Textron, Inc. (BHTI) Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters, that requires installing a safety washer kit designed to preclude separation of the stabilizer bar damper link (damper link) if the damper link rod end bushing (bushing) loosens and exits the damper link rod end. This amendment is prompted by two reported incidents in which the bushings loosened and exited the damper link rod ends, allowing the damper link to slide over the retention bolt and separate from the stabilizer bar (in the first incident), and from the hydraulic damper (in the second incident). The actions specified by this AD are intended to prevent failure of the damper link assembly, which can result in degraded control response and subsequent loss of control of the helicopter.

Final rule

98-07-09 BELL HELICOPTER TEXTRON, INC.: Amendment 39-10429. Docket No. 96-SW-28-AD.

Applicability: Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters, certificated in any 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 the next 100 hours time-in-service or within the next 120 calendar days, whichever occurs first, unless accomplished previously.

To prevent failure of the stabilizer bar damper link assembly, which can result in degraded control response and subsequent loss of control of the helicopter, accomplish the following:

(a) Remove the stabilizer bar damper link assemblies from the helicopter, install a safety washer kit, part number (P/N) CA-047-96-022-1, and reinstall the stabilizer bar damper link assemblies onto the helicopter in accordance with the Accomplishment Instructions contained in Bell Helicopter Textron, Inc. Alert Service Bulletin No. 47-96-22, dated August 16, 1996.

(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) The installation shall be done in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin No. 47-96-22, dated August 16, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on May 6, 1998.

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 BHTI Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters was published in the Federal Register on May 20, 1997 (62 FR 27554). That action proposed to require installing a safety washer kit designed to preclude separation of the damper link if the bushing loosens and exits the damper link rod end.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the one comment received.

The commenter states that the helicopters are controllable with one damper link disconnected. The commenter also states that a standard AN970-3 safety washer drilled out to 0.250-inch and coned should be allowed to be used as an alternate part to the BHTI safety washer kit. The commenter states that the modified AN970-3 safety washer is the same configuration as the BHTI safety washers used on the lateral cyclic torque tube and only costs pennies.

The FAA does not concur with the comment. The commenter did not provide any support for his statement that the helicopters are controllable with one damper link disconnected. The commenter indicates that he has been installing a modified safety washer on BHTI Model 47 series helicopters for decades. Although the commenter may believe that his modified safety washer is as airworthy as BHTI s safety washer, he has provided no engineering design data that support his assertion or show that his modified safety washer is of the same configuration or of the same material quality as BHTI s safety washer. Without such supporting data, the FAA cannot approve the use of the commenter s modified safety washer.

After careful review ofthe available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

The FAA estimates that 1,868 helicopters of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $188 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $463,264.

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 that this 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, Incorporation by reference, 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 U.S.C. 106(g), 40113, 44701.

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