On November 3, 2000, the FAA issued AD 2000-23-51, which required a one-time fluorescent penetrant inspection of the shaft. That AD was prompted by the discovery of a cracked shaft having 477 hours TIS. Since the issuance of that AD, additional incidents of cracked shafts occurred, and we determined that additional inspections are required. On November 9, 2000, we issued superseding Emergency AD 2000-23-52, for Sikorsky Model S-76A, S-76B, and S-76C helicopters, which requires an initial and recurring fluorescent penetrant inspections of the shaft. Also required, before the first flight of each day, are visual inspections for any crack. If any crack is found, the shaft must be replaced before further flight with an airworthy shaft.
The FAA has reviewed Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-66-31, Revision B, dated November 7, 2000, which describes procedures for inspecting the shaft, part number 76351-09030 series and 76351-09630 series. In addition to requiring the inspections prescribed in this alert service bulletin, the FAA has determined that certain shafts, part number 76351-09030 series, serial numbers with a prefix of "B" and numbers 015-00700 through 00706, must be removed from service because the three cracked shafts discovered thus far came from that manufacturing lot.
Since the unsafe condition described is likely to exist or develop on other Sikorsky Model S-76A, S-76B, and S-76C helicopters of the same type designs, the FAA issued superseding Emergency AD 2000-23-52 to prevent failure of the shaft and subsequent loss of control of the helicopter. The AD requires, before further flight, performing a fluorescent penetrant inspection of the shaft in the area above the upper shaft output seal and below the lower hub attachment flange. Thereafter, recurring fluorescent penetrant inspections are required at specified time intervals and visual inspections using a 10x or higher magnifying glass are required before the first flight of each day. If any crack is found, the shaft must be replaced before further flight with an airworthy shaft that has been inspected in accordance with the requirements of this AD. The actions must be accomplished in accordance with the alert service bulletin described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity and controllability of the helicopter. Therefore, the actions stated previously are required before further flight and at the specified time intervals, 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 November 9, 2000, to all known U.S. owners and operators of Sikorsky Model S-76A, S-76B, and S-76C helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to 14 CFR 39.13 to make it effective to all persons. However, there was an error in the preamble section of the emergency AD; the superseded AD number is 2000-23-51, the emergency AD incorrectly referenced AD 2000-53-21. The correction to the superseded AD number is made in this AD; the FAA has determined that this change will neither increase the economic burden on an operator nor increase the scope of the AD.
The FAA estimates that 172 helicopters of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per helicopter to accomplish the fluorescent inspection, work hour per helicopter to perform each visual inspection, and 8 work hours per helicopter to replace the shaft, if necessary, and that the average labor rate is $60 per work hour. Required parts, if a shaft needs to be replaced, will cost approximately $25,000 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $2,913,680 per year (assuming $41,280 for the initial fluorescent inspections; $206,400 for 5 repetitive inspections on each helicopter; $516,000 for 100 visual inspections on each helicopter; and $2,150,000 to replace the shaft on half of the 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 mailed 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. 2000-SW-61-AD." The postcard will be date stamped and returned to the commenter.
The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.
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: