COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace BAe 146 Series Aeroplanes AD/BAe 146/4 Amdt 1 Flight Controls - Stall Identification 1/87 Applicability: Series 100 and 100A, and Series 200 and 200A, fitted with the suspect valves identified in the Requirement Document. Requirement: Action in accordance with British Aerospace Service Bulletin 27-58. Note: SB 27-58 supersedes SB 27-53. Compliance: Inspect within 60 flights after 2 May 1986 and thereafter at intervals not exceeding 60 flights until replaced with modified valve. For spares prior to installation in an aircraft and thereafter a intervals not exceeding 60 flights until replaced with modified valve. Background: A number of stick push valves in service may become defective as a result of internal corrosion within the solenoid assembly. This could lead to a dormant failure not apparent on the flight deck.