COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Embraer EMB-120 (Brasilia) Series Aeroplanes AD/EMB-120/2 APU Electronic Control Unit 4/91 Applicability: All Embraer 120 aircraft as detailed in the Requirement Document. Requirement: Action in accordance with the technical requirements of Brazilian AD 90-09-02 R1 dated 14 January 1991. Note: Embraer SB NR 120-053-0049 also refers. Compliance: As specified in the Requirement Document with an effective date of 18 April 1991. Background: It has been determined that the EMB 120 APU Electronic Control Unit may be subject to accidental water contamination during aircraft washing which may result in malfunction of the APU overspeed control which could affect safety of flight.