COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES SAAB SF340 Series Aeroplanes AD/SF340/11 Pitot Systems Water Traps 11/88 Applicability: Model SF340A with serial numbers 004 through 138. Requirement: Action in accordance with SAAB Scania AB Service Bulletin SF340-34-056 dated 1 August 1988 or later revision. Note: Swedish Airworthiness Directive No. 1-027 refers. Compliance: Prior to 31 December 1988. Background: Water intrusion into the pitot systems may occur in heavy rain. This can result in ice blocking the systems leading to erroneous air data signals.