On September 2, 1999, the FAA issued Emergency Priority Letter AD 99-19-23, applicable to Eurocopter France Model EC 120B helicopters, which requires, within 10 hours time-in- service (TIS), and thereafter, at intervals not to exceed 10 hours TIS, inspecting the engine coupling tube for cracks and replacing any cracked engine coupling tube with an airworthy engine coupling tube. That action was prompted by the discovery, during routine maintenance inspections, of three cracked engine coupling tubes caused by structural resonance. This condition, if not corrected, could result in coupling failure, loss of engine drive, and a subsequent forced landing.
Eurocopter France has issued Eurocopter Service Telex No. 05-001 EC 120, Version B, dated August 26, 1999, which describes procedures for checking the coupling tube assembly, part number (P/N) C631A1002101, on the engine- to-main gearbox coupling. The Direction Generale De L'Aviation Civile (DGAC), which is the airworthiness authority for France, classified this service telex as mandatory and issued telegraphic AD No. T1999-349-002(A) R1, dated August 27, 1999, to ensure the continued airworthiness of these helicopters in France.
This helicopter model is manufactured in France and is type certificated for operation in the United States under the provision 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 DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operations in the United States.
Since the unsafe condition described is likely to exist or develop on other Eurocopter France Model EC 120 helicopters of the same type design, the FAA issued Emergency Priority Letter AD 99-19-23 to detect a crack in the engine coupling tube which could result in coupling failure, loss of engine drive, and a subsequent forced landing. The AD requires, within 10 hours TIS, and thereafter, at intervals not to exceed 10 hours TIS, inspecting the engine coupling tube, P/N C631A1002101, for cracks and replacing any cracked engine coupling tube with an airworthy engine coupling tube. The actions must be accomplished in accordance with the service telex described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter. Therefore, inspecting the engine coupling tube for any crack and replacing any cracked engine coupling tube is required within 10 hours TIS, 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, 1999, to all known U.S. owners and operators of Eurocopter France Model EC 120B 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 12 helicopters of U.S. registry will be affected by this AD; it will take approximately 2 work hours per helicopter to inspect the engine coupling tube; 4 work hours to replace the engine coupling tube, if necessary; and the average labor rate is $60 per work hour. Required parts, if the engine coupling tube is replaced, will cost approximately $4,020 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $39,960 per year, assuming 10 inspections per helicopter and replacement of the engine coupling tube on 6 helicopters.
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. 99-SW-53-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: