Airworthiness Directive · Amendment 39-11766 · Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2 and N3; and SA-366G1 Helicopters
Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2 and N3; and SA-366G1 Helicopters
Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2 and N3; and SA-366G1 helicopters, certificated in any category.
Note 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.
This amendment supersedes an existing airworthiness directive (AD) that applies to Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2, and SA-366G1 helicopters. That AD currently requires inspecting the tightening torque of the main rotor hub blade attach beam spherical thrust bearing bolts (bolts) and either applying a specified torque or, if necessary, inspecting for a crack in the metal components. That AD also requires replacing the spherical thrust bearing (bearing) with an airworthy bearing if a crack is found. This amendment requires the same actions as the existing AD, but adds the Eurocopter France Model AS-365N3 helicopter to the applicability. This amendment is prompted by reports of cracks in the metal components of the bearing attachment joint and the need to add the Eurocopter France Model AS-365N3 helicopter to the applicability. 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.
To 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:
(a) Inspect the tightening torque of the bolts as indicated by “A” in Figure 1.
(1) If 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.
(i) If a crack is detected, replace the bearing with an airworthy bearing.
(ii) If no crack is detected, reinstall the bearing.
Note 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.
(2) If the tightening torque is greater than 12 m.daN (88.4 lb-ft), then tighten the torque to 19-22 m.daN (140-162.2 lb-ft).
