AD 98-11-14

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-11-14 which was sent previously to all known U.S. owners and operators of Bell Helicopter Textron, Inc. (BHTI) Model 205A-1 and 205B helicopters by individual letters. This AD requires inspecting the trunnion assembly or tail rotor flapping stop (flapping stop), whichever is applicable, installing a trunnion assembly or flapping stop, if necessary; and replacing the tail rotor yoke (yoke). This amendment is prompted by an accident involving a BHTI Model 205A-1 helicopter in which the yoke failed during flight. This condition, if not corrected, could lead to failure of the yoke, loss of the tail rotor, and subsequent loss of control of the helicopter.

Final rule; request for comments

98-11-14 BELL HELICOPTER TEXTRON, INC.: Amendment 39-11011. Docket No. 98-SW-21-AD.

Applicability: Model 205A-1 helicopters, with tail rotor yoke assembly, part number (P/N) 212-011-702-all dash numbers, or P/N 212-010-704-all dash numbers, or P/N 212-010-744-all dash numbers, and Model 205B helicopters, with tail rotor yoke assembly, P/N 212-011-702-all dash numbers, 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 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 (d) 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 as indicated, unless accomplished previously.

To prevent failure of the tail rotor yoke (yoke), loss of the tail rotor, and subsequent loss of control of the helicopter, accomplish the following:

(a) Before further flight, review all historical records of the helicopter and the tail rotor yoke assembly (yoke assembly) for any static or dynamic incident history that could have imposed an excessive bending load on the yoke. If such a history exists, comply with paragraph (b) of this AD before further flight.

NOTE 2: Examples of excessive bending loads include exposure to high wind gusts (such as those from rotor wash orprop blast), improper ground handling (in which the tail rotor blade has been used as a hand hold), improper feathering bearing removal (in which the yoke is not properly supported when pressing out bearings), a static ground strike of some type (such as being struck by a vehicle), or an incident in which a damaged tail rotor blade was replaced due to a blade strike. An overload may also occur dynamically during a power-on or power-off sudden stoppage incident or hard landing.

(b) Within the next 180 calendar days, remove the yoke assembly and replace it with an airworthy yoke assembly having zero hours time-in-service (TIS), or with an airworthy yoke assembly (regardless of TIS) that has passed an x-ray diffraction inspection in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) 205-96-68, Revision A, dated May 18, 1998, or ASB 205-96-69 or ASB 205B-96-25, both dated September 3, 1996, whichever is applicable. When the yoke assembly is replaced, for helicopters with a yoke assembly, P/N 212-011-702-all dash numbers, install an airworthy tail rotor flapping stop, P/N 212-011-713-103, and for helicopters with yoke assemblies, P/N 212-010-704-all dash numbers or P/N 212-010-744-all dash numbers, install an airworthy trunnion assembly, P/N 212-010-738-001. If any incident as described in paragraph (a) of this AD occurs after the effective date of this AD and prior to compliance with this paragraph, then compliance with this paragraph is required before further flight.

NOTE 3: Yoke assemblies that have passed an x-ray diffraction inspection at BHTI will have the letters "FM" vibro-etched on them following the serial number.

(c) After accomplishing the requirements of paragraph (b) of this AD, thereafter at intervals not to exceed 25 hours TIS, or before further flight after any incident as described in paragraph (a) of this AD, inspect the trunnion assembly, and replace the yoke assembly and trunnion assembly, if required, in accordance with Part III, Paragraph 1, of ASB 205-96-68, Revision A, dated May 18, 1998; or inspect the flapping stop and replace the yoke assembly and flapping stop, if required, in accordance with Part III, Paragraphs 1, 2, and 3, of ASB 205-96-69 or ASB 205B-96-25, both dated September 3, 1996, whichever is applicable.

(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, Rotorcraft Certification Office, Rotorcraft Directorate. 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, Rotorcraft Directorate.

NOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Certification Office.

(e) Special flight permits may be issued in accordance with sections21.197 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) The repetitive inspections shall be done in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) No. 205-96-68, Revision A, dated May 18, 1998, which specifies inspections of the yoke and trunnion assemblies, and replacement of certain trunnion assemblies; and ASB 205-96-69 and ASB 205B-96-25, both dated September 3, 1996, which specify inspections of the yoke assembly and installation of a flapping stop. 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 MeachamBlvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on February 10, 1999, to all persons except those persons to whom it was made immediately effective by Priority Letter AD 98-11-14, issued May 19, 1998, which contained the requirements of this amendment.

On May 19, 1998, the FAA issued Priority Letter AD 98-11-14, applicable to BHTI Model 205A-1 and 205B helicopters, which requires, before further flight, reviewing historical records of the helicopter and yoke assembly to detect any usage or event that may have imposed an excessive bending load on the yoke. If such usage or event occurred, before further flight, the priority letter AD requires replacing the yoke assembly with an airworthy yoke assembly that has zero-hours time-in-service (TIS) or that has passed an x-ray diffraction inspection in accordance with BHTI s service bulletins, as well as installing an airworthy trunnion assembly or an airworthy flapping stop, depending on which part-numbered yoke assembly is installed. If no such usage or event has occurred, the yoke must be replaced within 180 calendar days. Thereafter, at intervals not to exceed 25 hours TIS, or before further flight after any incident that may have imposed an excessive bendingload on the yoke, this AD requires inspecting the trunnion assembly or the flapping stop, whichever is applicable, for yielding. If yielding is detected, replacing the yoke assembly and trunnion assembly or flapping stop, whichever is applicable, is required. That action was prompted by an accident involving a BHTI Model 205A-1 helicopter in which the yoke failed during flight. Investigation of the accident revealed that the yoke assembly service life may be reduced due to unforeseen static and dynamic loading of the tail rotor. This condition, if not corrected, could lead to failure of the yoke, loss of the tail rotor, and subsequent loss of control of the helicopter.

The FAA has reviewed Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) No. 205-96-68, Revision A, dated May 18, 1998, which specifies inspecting the yoke and trunnion assemblies, and replacing certain trunnion assemblies; and ASB 205-96-69 and ASB 205B-96-25, both dated September 3, 1996, which specify inspecting the yoke assembly and installing a flapping stop.

Since the unsafe condition described is likely to exist or develop on other BHTI Model 205A-1 and 205B helicopters of the same type design, the FAA issued Priority Letter AD 98-11-14 to prevent failure of the yoke, loss of the tail rotor, and subsequent loss of control of the helicopter. The AD requires, before further flight, reviewing historical records of the helicopter and yoke assembly to detect any usage or event that may have imposed an excessive bending load on the yoke. If such usage or event occurred, this AD requires, before further flight, replacing the yoke assembly with an airworthy yoke assembly that has zero-hours TIS, or that has passed an x-ray diffraction inspection in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) 205-96-68, Revision A, dated May 18, 1998, or ASB 205-96-69 or ASB 205B-96-25, both dated September 3, 1996, whichever is applicable, as well as installing an airworthy trunnion assembly or an airworthy flapping stop, depending on which part-numbered yoke assembly is installed. If no such usage or event has occurred, the yoke must be replaced within 180 calendar days. Thereafter, at intervals not to exceed 25 hours TIS, or before further flight after any incident that may have imposed an excessive bending load on the yoke, this AD requires inspecting the trunnion assembly or the flapping stop, whichever is applicable, for yielding. If yielding is detected, replacing the yoke assembly and trunnion assembly or flapping stop, whichever is applicable, is required. 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 both the controllability and structural integrity of the helicopter. Therefore, the previously-stated actions are required prior to further flight, and this AD must be issued immediately.

Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on May 19, 1998 to all known U.S. owners and operators of BHTI Model 205A-1 and 205B helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons.

The FAA estimates that 495 helicopters of U.S. registry will be affected by this AD; that it will take approximately 9 work hours per helicopter to conduct the inspections, install the trunnion assembly or flapping stops, and replace the yoke; and that the average labor rate is $60 per work hour. Required parts will cost approximately $1,028 for a trunnion assembly or $936 for the flapping stops and $6,637 for the yoke, per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $4,061,475 to replace both the trunnion assembly and the yoke in the entire fleet.

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-21-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 therelationship 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: