On May 19, 1998, the FAA issued priority letter AD 98-11-15, applicable to BHTI Model 212 helicopters, which requires, before further flight, reviewing historical records of the helicopter and the 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, this AD requires 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) 212-96-100, Revision A, dated May 18, 1998, or ASB 212-96-101, 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 usage or event that may have imposed an excessive bending load on the yoke 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 tail rotor flapping stop, whichever is applicable, for yielding. If yielding is detected, the yoke assembly and trunnion assembly or flapping stop, whichever is applicable, must be replaced. That action was prompted by an accident involving a BHTI Model 205A-1 helicopter in which the yoke failed during flight. The Model 205A-1 helicopter is similar in design to the Model 212 helicopter. 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 ServiceBulletin (ASB) No. 212-96-100, Revision A, dated May 18, 1998, which specifies inspections of the yoke assembly and trunnion assembly, and replacement of certain trunnion assemblies; and ASB 212-96-101, dated September 3, 1996, which specifies inspections of the yoke assembly, and installation of a tail rotor flapping stop.
Since an unsafe condition has been identified that is likely to exist or develop on other BHTI Model 212 helicopters of the same type design, this AD requires, before further flight, reviewing historical records of the helicopter and the 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, this AD requires 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 ASB 212-96-100, Revision A, dated May 18, 1998, or ASB 212-96-101, 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 tail rotor flapping stop, whichever is applicable, for yielding. If yielding is detected, the yoke assembly and trunnion assembly or flapping stop, whichever is applicable, must be replaced. 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 controllability and structural integrity of the helicopter, and the yoke assembly may need to be replaced 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 212 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 250 helicopters of U.S. registry will be affected by this AD, that it will take approximately 9 work hours per helicopter to accomplish the inspections and installations, and that the average labor rate is $60 per work hour. Required parts will cost approximately $6,637 for each yoke, $1,028 for each trunnion assembly, and $936 for each flapping stop per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $2,051,250 if both the yoke and the trunnion assembly are replaced 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-20-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: