AD 99-21-24

This amendment adopts a new airworthiness directive (AD), applicable to Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2; and SA-366G1 helicopters, that requires inspecting the tightening torque of the main rotor hub blade attach beam spherical thrust bearing bolts (bolts). This AD also requires either applying the specified torque or, if necessary, conducting a dye penetrant inspection for cracks in the metal components. Replacing the spherical thrust bearing (bearing) with an airworthy bearing is also required if a crack is found. This amendment is prompted by reports of cracks in the metal components of the bearing attachment joint. The actions specified by this AD are intended to prevent loosening of bearing bolts in flight, which may cause cracks in the metal components, failure of the bearing, and subsequent loss of control of the helicopter.

Final rule

99-21-24 EUROCOPTER FRANCE: Amendment 39-11369. Docket No. 98-SW-75-AD. \n\tApplicability: Model SA-365C, C1, C2, N, and N1; AS-365N2; and SA-366G1 helicopters, certificated in any category. \n\n\tNOTE 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. \n\n\tCompliance: Required within 550 hours time-in-service (TIS), unless accomplished previously, and thereafter at intervals not to exceed 550 hours TIS. \n\n\tTo prevent loosening of the main rotor hub blade attach beam spherical thrust bearing bolts (bolts), cracks in the metal components, failure of a spherical thrust bearing (bearing), and subsequent loss of control of the helicopter, accomplish the following: \n\n\t(a)\tInspect the tightening torque of the bolts as indicated by "A" in Figure 1. \n\n\t\t(1)\tIf tightening torque is equal to or less than 12 m.daN (88.4 lb-ft), remove the bearing and conduct a dye penetrant inspection for cracks on the two contact surfaces identified as "H" in Figure 1. \n\t\t\t(i)\tIf a crack is detected, replace the bearing with an airworthy bearing. \n\t\t\t(ii)\tIf no crack is detected, reinstall the bearing. \n\n\tNOTE 2: Eurocopter France Service Bulletins 05.22, 05.24, and 05.00.39, all dated July 17, 1998, pertain to the subject of this AD. \n\n\t\t(2)\tIf the tightening torque is greater than 12 m.daN (88.4 lb-ft), then tighten to 19-22 m.daN (140-162.2 lb-ft). \n\n\t(b)\tAn alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Rotorcraft Standards Staff, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff. \n\n\tNOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff. \n\n\t(c)\tSpecial flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be accomplished. \n\n\tNOTE 4: The subject of this AD is addressed in Direction Generale De L'Aviation Civile (France) AD's 98-383-044(A) for the Model SA-365C, 98-382-024-(A) for the Model SA-366, and 98-384-047(A) for the Model AS-365N helicopters. These AD's are all dated September 23, 1998. \n\n\t(d)\tThis amendment becomes effective on November 18, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2; and SA- 366G1 helicopters was published in the Federal Register on July 9, 1999 (64 FR 37046). That action proposed to require inspecting the tightening torque of the bolts and either applying a specified torque or, if necessary, conducting a dye penetrant inspection for cracks in the metal components. Replacing the bearing with an airworthy bearing was also proposed if a crack was found. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\n\tThe FAA estimates that 100 helicopters of U.S. registry will be affected by this AD, that it will take approximately 0.5 work hour and approximately 3,000 inspections over the life of the fleet per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $3,000 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $9,030,000 assuming 10 ship sets of bearings would need to be replaced on the fleet. \n\n\tThe 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. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. \n\nList of Subjects in 14 CFR Part 39 \n\tAir transportation, Aircraft, Aviation safety, Safety. \n\nAdoption of the Amendment \n\tAccordingly, 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: \n\nPART 39 - AIRWORTHINESS DIRECTIVES \n\t1. The authority citation for part 39 continues to read as follows: \n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\t2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: