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 369/55 Main Gear Box Ring Gear Carrier Shaft - Inspection 11/82 Applicability: All model 369D series helicopters fitted with main transmission P/N 369D25100 - Basic Configuration. Note: Transmissions with a letter "U" prefix to the serial number on the transmission ID plate, or transmissions P/N 369D25100-501 and later suffix number configurations are not affected by this Directive. Document: Hughes SIN No. DN-105. Note: FAA AD 82-17-01 refers. Compliance: Inspect in accordance with Part 1 of the document within 100 hours time in service after 30 November 1982, and thereafter at periods not exceeding 300 hours time in service. Inspections in accordance with Part 1 may be discontinued subsequent to inspection in accordance with Part II of the document. Background: Cracks have been found in the electron beam welded junction of the lower disc of the ring gear carrier and the output shaft of the main gear box.