COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace BAe 3100 (Jetstream) Series Aeroplanes AD/JETSTREAM/1 Fuselage Drain Holes - Modification 8/84 Applicability: All Jetstream Series 3100 aircraft with S/Nos 601, 603, 604, 608 to 624 and 627. Requirement: British Aerospace Service Bulletin 53-JM7389. Compliance: Prior to issue of the next Maintenance Release after 31 August 1984. Background: Cases have occurred in service of water draining from the fuselage drain valve at STN 255 onto the flap micro-switches. This water has frozen causing malfunction of the flap operating system.