{"id":"F2006B03498","name":"AD/BAe 146/47 - Windshear Detection and Recovery System","slug":"ad-bae-146-47-windshear-detection-and-recovery-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43052,"registerId":"commonwealth-F2006B03498-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/47 - Windshear Detection and Recovery System","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBritish Aerospace BAe 146 Series Aeroplanes\n\nAD/BAe 146/47 Windshear Detection and Recovery System 10/93\n\nApplicability: All series BAe 146 aircraft equipped with a Safeflight Windshear Computer introduced by BAe Modification HCM40270A&B.\n\nRequirement: Action in accordance with British Aerospace BAe 146 Alert Inspection Service Bulletin S.B.34-A155 dated 9 July 1993.\n\nNote: Compliance with this Service Bulletin has been classified as Mandatory by the CAA(UK).\n\nCompliance: Prior to further flight after 30 September 1993 and thereafter at each subsequent \\`A’ check or after 300 flight cycles, whichever is the sooner, until a modified Safeflight Windshear Computer is installed.\n\nBackground: BAe have received reports that the windshear computer may not detect the loss of flap position signal, this may result in incorrect guidance information being displayed on the flight director. Compliance with this Directive will increase the possibility of early detection of the fault.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted airworthiness directive addressing a specific technical fault in a specific aircraft system. It has not expanded beyond its original purpose of ensuring the windshear computer functions correctly."},"complexity_factors":["Single, specific applicability criterion (one aircraft series with one specific modification)","Single requirement referencing an external technical document (Service Bulletin)","Simple compliance timeline with clear endpoint (until modified part installed)","No defined terms section, no cross-references to other legislation beyond the enabling regulations","Straightforward conditional logic (if equipped with X, then do Y)","Total length: approximately 150 words"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) for a specific type of aircraft — the British Aerospace BAe 146 series.\n\n**What it does:**\nIt requires airlines and aircraft operators to inspect or test the **windshear detection computer** on these planes. Windshear is a sudden change in wind speed or direction that can be dangerous during takeoff and landing. The computer helps warn pilots and guide them to safety.\n\n**The problem:**\nThe manufacturer found that the computer might fail to notice if it loses the signal telling it what position the aircraft's flaps are in. Flaps are the movable surfaces on the wings that help control lift during takeoff and landing. If the computer doesn't know the flap position, it might give pilots the wrong guidance during a windshear emergency.\n\n**Who must act:**\nAnyone operating a BAe 146 aircraft that has the specific Safeflight Windshear Computer installed (added via a particular modification kit).\n\n**What they must do:**\nFollow the instructions in British Aerospace Service Bulletin S.B.34-A155. This involves checking the system before flying after 30 September 1993, and then repeating the check at every 'A' maintenance check or every 300 flights — whichever comes first. The repeated checks stop once a modified (fixed) computer is installed.\n\n**Why it matters:**\nThis is a **mandatory safety measure**. The UK aviation regulator (CAA) classified compliance as mandatory, and Australia's CASA has adopted it. It reduces the risk of pilots receiving dangerous incorrect information during hazardous weather conditions."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive sets a focused, interim inspection and upgrade requirement for BAe 146 aircraft with the specified Safeflight computer. The text contains no amendment or expansion of applicability beyond the stated aircraft/modification and no indication that scope has been changed from the instrument's own stated intent."},"complexity_factors":["Narrow technical applicability — only BAe 146 series aircraft with a Safeflight Windshear Computer installed by BAe Mod HCM40270A&B (Applicability).","Dependency on external technical document — compliance requires action in a specific BAe Alert Inspection Service Bulletin S.B.34-A155 dated 9 July 1993 (Requirement).","Time-bound and recurring compliance — initial action required before further flight after 30 September 1993, then at each 'A' check or after 300 flight cycles, whichever is sooner (Compliance).","Interim measure until hardware change — inspections continue only until a modified Safeflight Windshear Computer is installed, introducing staging and tracking obligations for operators (Compliance).","Safety risk tied to a specific fault mode — background states the winds heel computer may not detect loss of flap position signal, which can produce incorrect flight‑director guidance (Background).","Regulatory reinforcement from another authority — the Service Bulletin is classified as Mandatory by CAA(UK), creating cross-jurisdictional compliance expectations (Note)."],"plain_english_summary":"This Directive requires operators of BAe 146 aircraft fitted with the Safeflight Windshear Computer (BAe Mod HCM40270A&B) to carry out the inspection and actions in BAe Alert Inspection Service Bulletin S.B.34‑A155. Inspections must occur before further flight after 30 September 1993 and thereafter at each ‘A’ check or every 300 flight cycles until a modified computer is installed. It responds to reports that loss of the flap position signal can produce incorrect flight‑director guidance, and places inspection and upgrade costs on aircraft operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-47-windshear-detection-and-recovery-system","history":"/api/acts/ad-bae-146-47-windshear-detection-and-recovery-system/history","analysis":"/api/acts/ad-bae-146-47-windshear-detection-and-recovery-system/analysis","conflicts":"/api/acts/ad-bae-146-47-windshear-detection-and-recovery-system/conflicts","importantCases":"/api/acts/ad-bae-146-47-windshear-detection-and-recovery-system/important-cases","documents":"/api/acts/ad-bae-146-47-windshear-detection-and-recovery-system/documents"}}