AD 98-19-13

On September 2, 1998, the FAA issued priority letter AD 98-19-13, applicable to BHTC Model 407 helicopters, which requires, on or before the accumulation of 50 hours total TIS on the driveshaft, replacing the driveshaft with an airworthy driveshaft. That action was prompted by analysis and test data that revealed that the life limit of the driveshaft is less than that which is stated in the applicable maintenance manual. The published life limit has been 2,500 hours TIS; however, new data indicate the life limit should be approximately 50 hours TIS. This condition, if not corrected, could result in failure of the driveshaft, loss of engine drive to the rotor system, damage to critical structural components, and subsequent loss of control of the helicopter.

The FAA has reviewed Bell Helicopter Textron Alert Service Bulletin No. 407-98-19, dated June 19, 1998, which describes procedures for replacing the driveshaft, part number (P/N) 206-340-300-103, with driveshaft, P/N 206-340-300-105, which has a longer service life.

Since the unsafe condition described is likely to exist or develop on other BHTC Model 407 helicopters of the same type design, the FAA issued priority letter AD 98-19-13 to prevent failure of the driveshaft, loss of engine drive to the rotor system, damage to critical structural components, and subsequent loss of control of the helicopter. The AD requires, on or before the accumulation of 50 hours total TIS on the driveshaft, replacing the driveshaft, P/N 206-340-300-103, with an airworthy driveshaft, P/N 206-340-300-105. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability of the helicopter. Therefore, replacing the driveshaft is required within 50 hours, 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 September 2, 1998, to all known U.S. owners and operators of BHTC Model 407 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 146 helicopters of U.S. registry will be affected by this AD, that it will take approximately 5 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $24,500 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $3,620,800.

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 afterthe 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-43-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 hasdetermined 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, 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: