AD 98-23-18

This amendment adopts a new airworthiness directive (AD) that is applicable to Bell Helicopter Textron, Inc. (Bell) Model 214B, 214B-1, and 214ST helicopters. This action requires a visual inspection of thin-flanged attachment barrel nuts (barrel nuts) manufactured by Kaynar Technologies, Inc. for cracks or lubrication residue, and replacement of the barrel nuts and corresponding attaching bolts, as necessary. These barrel nuts have been installed in main rotor grips, pitch horns, and tailboom assemblies. This amendment is prompted by a report of a cracked barrel nut, which was discovered on a helicopter being prepared for shipment. The actions specified in this AD are intended to detect cracks in a barrel nut, which could lead to failure of a main rotor grip, pitch horn, or tailboom, and subsequent loss of control of the helicopter.

Final rule; request for comments

98-23-18 BELL HELICOPTER TEXTRON, INC.: Amendment 39-10886. Docket No. 98-SW-12-AD.

Applicability: Model 214B, 214B-1, and 214ST 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 (e) 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 40 hours time-in-service, unless accomplished previously.

To detect cracks in a barrel nut, which could lead to failure of a main rotor grip, pitch horn, or tailboom, and subsequent loss of control of the helicopter, accomplish the following:

(a) For each barrel nut, determine if the manufacturer was Kaynar Technologies Inc. (Kaynar) in accordance with paragraph 1.a. of the Accomplishment Instructions of Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) No. 214-97-59, applicable to Model 214B and B-1 helicopters, or Bell Helicopter Textron, Inc. ASB No. 214ST-97-78, applicable to Model 214ST helicopters, both dated July 17, 1997.

(b) For each Kaynar-manufactured barrel nut, part number (P/N) NAS577B-10A, determine if it is a "thick" flange barrel nut (installed edge distance of 0.115-inch) or a "thin flange barrel nut (installed edge distance of 0.155-inch) in accordance with paragraph 1.b of the Accomplishment Instructions of the applicable ASB, dated July 17, 1997.

(c) For each barrel nut identified as a Kaynar-manufactured "thin" flange barrel nut, using a 10-power or higher magnifying glass, perform a visual inspection for cracks in the threaded portion of each barrel nut or lubrication residue in the threaded portion of each barrel nut or its corresponding attaching bolt.

NOTE 2: If a "thick" flange Kaynar-manufactured barrel nut, P/N NAS577B-10A, is installed, compliance with paragraphs (d) and (e) of this AD is not required.

(d) For each barrel nut that cannot be positively identified, and for each Kaynar-manufactured "thin" flange barrel nut in which a crack or lubrication residue was discovered as a result of the inspection required by paragraph (c) of this AD, replace the barrel nut and the corresponding attaching bolt with an airworthy barrel nut and attaching bolt before further flight. Ifan unairworthy barrel nut is found at the right-hand upper tailboom attachment location, also replace the left-hand upper barrel nut and corresponding bolt, and inspect both upper tailboom and fuselage longeron fittings for damage or deformation.

(e) 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, FAA, Rotorcraft Directorate, Rotorcraft Certification Office. 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Certification Office.

(f) 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 thehelicopter to a location where the requirements of this AD can be accomplished.

(g) The identification and determination of the barrel dimensions shall be done in accordance with Bell Helicopter Textron, Inc. ASB No. 214-97-59 or Bell Helicopter Textron, Inc. ASB No. 214ST-97-78, both dated July 17, 1997. 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, telephone (817) 280-3391, fax (817) 280-6466. 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.

(h) This amendment becomes effective on November 30, 1998.

This amendment adopts a new airworthiness directive (AD) that is applicable to Bell Helicopter Textron, Inc. (Bell) Model 214B, 214B-1, and 214ST helicopters. This action requires an inspection of barrel nuts manufactured by Kaynar Technologies, Inc. (Kaynar). This amendment is prompted by the discovery of a cracked barrel nut, part number NAS577B-10A, on a helicopter being disassembled for shipment. The crack was in the threaded portion of the barrel nut. A laboratory analysis indicated that the cracking is a result of hydrogen embrittlement introduced during manufacture. These nuts may have been installed in spare main rotor grips, pitch horns, or tailboom assemblies; and may also have been supplied as individual spare parts. The actions specified in this AD are intended to detect cracks in a barrel nut, which could lead to failure of a main rotor grip, pitch horn, or tailboom, and subsequent loss of control of the helicopter.

The FAA has reviewed Bell Helicopter Textron, Inc. Alert Service Bulletin No. 214-97-59 and Bell Helicopter Textron, Inc. Alert Service Bulletin No. 214ST-97-78, both dated July 17, 1997, which describe procedures for determining if any barrel nuts used on the affected model helicopters were manufactured by Kaynar, and if so, visually inspecting those barrel nuts for cracks or lubrication residue using a 10-power or higher magnifying glass. If a crack or lubrication residue is discovered in the threads of either a barrel nut or its attaching bolt, both the barrel nut and the attaching bolt must be replaced with airworthy parts. Barrel nuts whose manufacturer cannot be positively identified must also be replaced.

Since an unsafe condition has been identified that is likely to exist or develop on other Bell Model 214B, 214B-1, and 214ST helicopters of the same type design, this AD is being issued to detect cracking in a barrel nut, which could lead to failure of a main rotor grip, pitch horn, or tailboom, and subsequent loss of control of the helicopter. The actions are required to be accomplished in accordance with the service bulletins described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter. Therefore, an inspection of the barrel nuts is required within 40 hours time-in-service, and this AD must be issued immediately.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

The FAA estimates that 15 helicopters of U.S. registry will be affected by this proposed AD, that it will take approximately 3.0 work hours per helicopter to accomplish the inspection and replacement of parts, and that the average labor rate is $60 per work hour. Required parts will cost approximately $600 per helicopter. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $11,700.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 98-SW-12-AD." The postcard will be date stamped and returned to the commenter.

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.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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: