COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES FLS Aerospace OA7 Optica Series Aeroplanes AD/OPTICA/4 Fan Shaft Extension 1/95 Applicability: All model OA7 Optica aircraft up to and including aircraft S/N 22 fitted with Hoffmann fan and fan shaft extension. Requirement: Action in accordance with FLS Aerospace LOVAUX Mandatory SB No B2/MSB/006 Issue 1. Note: UK CAA AD 010-08-94 refers. Compliance: As specified in the Requirement Document with a revised effective date of 5 January 1995. Background: The manufacturer has advised that due to an error in the manufacturing process, the depth of the four counter bores may have exceeded limits and this could result in reduced fan to engine attachment integrity.