COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Maule M-4 Series Aeroplanes AD/ML-M4/13 Horizontal Tail to Fuselage Front Attach Tubes - Inspection and Modification 3/80 Applicability: All M-4 series with S/Nos. as referenced in Maule Aircraft Corporation SB No. 1. Document: Maule Aircraft Corporation SB No. 1. Compliance: Unless already accomplished, within 100 hours time in service after 31 October 1979. Background: There is a possibility that the fuselage tube attaching the front attach point of the horizontal tail may be cracked.