AD 98-08-14

This amendment adopts a new airworthiness directive (AD) applicable to Eurocopter France (Eurocopter) Model SA-365N, N1 and AS-365N2 helicopters that requires inspections of the main gearbox suspension diagonal cross-member (diagonal cross-member) for cracks, and removal of the diagonal cross-member and replacement with an airworthy diagonal cross-member if any crack is found. This amendment is prompted by several reports of the discovery of cracks in diagonal cross-members. The actions specified by this AD are intended to prevent failure of the diagonal cross-member which could cause the main gearbox to pivot, resulting in severe vibrations and a subsequent forced landing.

Final rule.

98-08-14 EUROCOPTER FRANCE: Amendment 39-10463. Docket No. 97-SW-21-AD.

Applicability: Model SA-365N, N1, and AS-365N2 helicopter with main gearbox suspension diagonal cross-member (diagonal cross-member), part number (P/N) 365A38-3023-20, -21, -23, or -24, installed, certificated in any category.

NOTE 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been 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 use the authority provided in paragraph (d) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any helicopter from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the diagonal cross-member, which could cause the main gearbox to pivot, resulting in severe vibrations and a subsequent forced landing, accomplish the following:

(a) For Model SA-365N and N1 helicopters, prior to the accumulation of 50,000 operating cycles; and for Model AS-365N2 helicopters, prior to the accumulation of 30,000 operating cycles:

NOTE 2: The Master Service Recommendations and the flight log contain accepted procedures that are used to determine the cumulative operating cycles on the rotorcraft.

(1) Inspect the diagonal cross-member for cracks in the area of the center bore hole, using a borescope with a 90 angle drive, or a video assembly with optical fiber illumination, or any other appropriate device that makes it possible to visually inspect the center area of the part.

(2) Repeat the inspection required by paragraph (a)(1) of this AD at intervals not to exceed 500 operating cycles, or 100 hours time-in-service, whichever occurs first.

(b) If any crack is found as a result of the inspections required by paragraphs (a)(1) or (a)(2) of this AD, remove the diagonal cross-member and replace it with an airworthy diagonal cross-member.

(c) Installation of modification MOD 073880 that installs a diagonal cross-member, P/N 356A38-3062-20, constitutes a terminating action for the requirements of this AD.

(d) An 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.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff.

(e) Special 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.

NOTE 4: The subject of this AD is addressed in Direction Generale De L'Aviation Civile (France) AD 97-093-041(AB)R1, dated July 30, 1997.

(f) This amendment becomes effective on May 15, 1998.

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 Model SA-365N, N1 and AS-365N2 helicopters was published in the Federal Register on December 9, 1997 (62 FR 64785). That action proposed to require inspections of the diagonal cross-member for cracks, and to remove any diagonal cross-member and to replace it with an airworthy diagonal cross-member if any crack is found.

Interested 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 with the exception of some editorial changes. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.The FAA estimates that 47 helicopters of U.S. registry will be affected by this AD, that it will take approximately one work hour per helicopter to inspect the diagonal cross-member and 10 work hours per helicopter to replace the diagonal cross-member, if necessary, and that the average labor rate is $60 per work hour. Required parts will cost approximately $9,950. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $498,670, assuming one inspection per helicopter, and replacement of a diagonal cross-member on each helicopter.

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.

For 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 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: