On April 30, 1997, the FAA issued priority letter AD 97-10-04 to require, before further flight, inspecting certain blades to determine the anodizing date for certain pocket assemblies installed on the blade, and if a blade has a pocket assembly that was anodized by Poly-Metal Company from October 1, 1996 through December 31, 1996, replacing it with an airworthy blade. That action was prompted by the discovery of a manufacturing defect that may cause disbonding and separation of portions of a blade. This defect is the result of an anodizing process, used during the manufacture of the pocket assembly, that did not meet the Type Design specifications. That condition, if not corrected, could result in disbonding and separation of portions of the blade, subsequent excessive vibrations, and loss of control of the helicopter.
Since the issuance of that AD, Sikorsky Aircraft Corporation has issued Sikorsky Alert Service Bulletin (ASB) No. 61B15-29A, Revision A, dated May 9, 1997, which corrects two of the blade serial numbers listed in the ASB that were referenced in the priority letter AD.
Since an unsafe condition has been identified that is likely to exist or develop on other Sikorsky Aircraft Corporation Model S-61A, D, E, L, N, NM, R, and V helicopters of the same type design, this AD supersedes AD 97-10-04 to require, before further flight, inspecting certain blades to determine the anodizing date for certain pocket assemblies installed on the blade, and if a blade has a pocket assembly that was anodized by Poly-Metal Company during the period of October 1, 1996, through December 31, 1996, replacing it with an airworthy blade. The actions are required to be accomplished in accordance with the service bulletin described previously.
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.
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 overallregulatory, 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. 97-SW-18-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 USC 106(g), 40113, 44701.
39.13 - [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive (AD), Amendment 39-10126, to read as follows: