COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters
AD/HU 369/78 Four Bladed Tail Rotor Hubs 11/89
DM
All MDHC 369D and 369E series helicopters fitted with four-bladed tail rotor hub P/N 369D21700-3 unless the currently fitted hub has been previously inspected in accordance with the Requirement Document.
Inspect the tail rotor hub in accordance with MDHC S.I.N. DN-160 or EN-50 as applicable.
Maintenance organisations will note MDHCs offer to replace unserviceable items free of charge and are urged to inspect their spares inventory forthwith.
1. Helicopters with hub serial numbers 196 through 251 - before the accumulation of 10 hours component time in service after 11 September 1989.
2. All other affected helicopters - before the accumulation of 100 hours component time in service after 11 September 1989.
One hub has been returned from service with fatigue cracks. MDHC has determined that the cracks are a result of electrical arcing caused by poor anode contact during the Tiodize coating process during manufacture.