AD/DAUPHIN/49 - MRH Spherical Thrust Bearings/Attach Beams Attachment Bolts (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters

AD/DAUPHIN/49 MRH Spherical Thrust Bearings/Attach Beams Attachment Bolts

14/98

Applicability: SA 365 helicopters, versions C, C1, C2, and C3, and AS 365 helicopters, versions N, N1, N2, and N3, fitted with main rotor head spherical thrust bearings/attach beam attachment bolts, all part numbers.

Requirement: Check the tightening torque load of both the spherical thrust bearing/attach beam attachment bolts in accordance with the instructions specified in paragraph 2B of Eurocopter SA 365C Service Bulletin (SB) No. 05.22, or AS 365N SB No. 05.00.39, as applicable.

If the tightening torque is less than 12 m. daN:

Remove the spherical thrust bearing and check for cracks. If a crack is found, replace the spherical thrust bearing.

Note: DGAC AD 98-383-044(A) and AD 98-384-047(A) refer.

Compliance: Initially, when the spherical thrust bearing attachment bolts are required to be removed, but at the latest before the accumulation of 550 flying hours after 31 December 1998; thereafter at intervals not to exceed 550 flying hours.

This Airworthiness Directive becomes effective on 31 December 1998.

Background: The DGAC requires the actions specified by this Directive in order to prevent the formation of cracks in the metal components of the spherical thrust bearings, due to increased stress resulting from possible loosening of the attachment bolts.