The Civil Aviation Administration (CAA), which is the airworthiness authority for the United Kingdom (UK), recently notified the FAA that an unsafe condition may exist on Westland WG-30 series 100 and 100-60 helicopters. The CAA advises that when water gets into the blade sleeve it can cause bulging or swelling of a tie-bar that could result in failure of a tie-bar, loss of a main rotor blade, and subsequent loss of control of the helicopter.
Westland has issued Westland Helicopters Service Bulletin (SB) No. W30-62-34 and W30-62-35, both dated November 29, 1995, which specify procedures for conditional, dimensional, and radiographic inspections and replacement, if necessary, of the tie-bars. The actions specified in these service bulletins are intended to prevent loss of a main rotor blade due to bulging or swelling of a tie-bar, tie-bar failure, and subsequent loss of control of the helicopter. The CAA classified these service bulletins as mandatory and issued CAA ADs 010-11-95 and 011-11-95, both dated January 31, 1996, in order to assure the continued airworthiness of these helicopters in the UK.
These helicopter models are manufactured in the UK and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the CAA has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.
Since an unsafe condition has been identified that is likely to exist or develop on other Westland WG-30 series 100 and 100-60 helicopters of the same type design eligible for registration in the United States, this AD is being issued to preventloss of a main rotor blade due to failure of a tie-bar which could result in subsequent loss of control of the helicopter. This AD requires an initial visual inspection and replacement, if necessary, of the tie-bars and thereafter, at intervals not to exceed 220 hours TIS, replacement of each tie-bar with an airworthy tie-bar. The actions are required to be accomplished in accordance with the service bulletins described previously.
None of the Westland series 100 and 100-60 helicopters affected by this action are on the U.S. Register. All helicopters included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers that this rule is necessary to ensure that the unsafe condition is addressed in the event that any of these subject helicopters are imported and placed in the U.S. Register in the future.
Should an affected helicopter be importedand placed on the U.S. Register in the future, it would require approximately 25 work hours for the visual inspection and 25 work hours, if necessary, for the replacement of the tie-bars, at an average labor rate of $60 per work hour. Required parts would cost $17,600 per helicopter. Based on these figures, the cost impact of this AD would be $20,600 per helicopter, assuming that the tie-bars are replaced.
Since this AD action does not affect any helicopter that is currently on the U.S. Register, it has no adverse economic and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register.
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. Interestedpersons 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 contactconcerned 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. 97-SW-28-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 notice and prior public comment are unnecessary in promulgating this regulation and therefore, it can be issued immediately to correct an unsafe condition in aircraft since none of these model helicopters are registered in the United States, 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 part39) 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: