{"id":"F2006B03496","name":"AD/BAe 146/45 - Airbrake Feedback Spring","slug":"ad-bae-146-45-airbrake-feedback-spring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43050,"registerId":"commonwealth-F2006B03496-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/45 - Airbrake Feedback Spring","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  British Aerospace BAe 146 Series Aeroplanes\n\n \n\nAD/BAe 146/45 Airbrake Feedback Spring 5/93\n\nApplicability: All BAe 146 series aircraft fitted with Servo-Valve assemblies P/N 3799H1 (Fairy Hydraulics) incorporating Servo-Valve P/N 72189 (Abex) in the S/N range as specified in the Requirement Document.\n\n \n\nRequirement: Action in accordance with BAe 146 mandatory Service Bulletin 27-133.\n\n \n\nNote: UK CAA AD 018-01-92 and DGAC 92-096-IMP(B) refer.\n\n \n\nCompliance: By 30 June 1993.\n\n \n\nBackground: Advice has been received that due to faulty manufacture the Servo-Valve feedback spring may be fractured.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-limited safety directive addressing a specific manufacturing defect. It has not expanded beyond its original purpose of mandating inspection/replacement of faulty servo-valve springs in BAe 146 aircraft."},"complexity_factors":["Very short document (under 200 words)","Only 4 substantive sections: Applicability, Requirement, Compliance, Background","Single technical requirement referencing an external document (Service Bulletin 27-133)","No defined terms section, no cross-references to other legislation, no conditional logic or exceptions","Narrow scope: one specific aircraft type, one specific part, one specific manufacturing defect"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of specific British Aerospace BAe 146 aircraft to inspect or replace a faulty part — the \"Servo-Valve feedback spring\" in the airbrake system. The spring was manufactured with a defect that could cause it to break.\n\n**Who it affects:**\n- Owners and operators of BAe 146 series aircraft\n- Specifically those with certain hydraulic servo-valve assemblies made by Fairy Hydraulics and Abex, within specific serial number ranges\n\n**What must be done:**\nFollow the instructions in **BAe Service Bulletin 27-133** (a technical repair notice from the manufacturer). The directive references similar safety orders from UK and French aviation authorities.\n\n**Deadline:**\nAll affected aircraft had to comply by **30 June 1993**.\n\n**Why it matters:**\nA fractured feedback spring in the airbrake system could impair the aircraft's ability to slow down or control descent — a serious flight safety risk. This directive ensures the defect is fixed before it causes an accident."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD’s scope is clearly stated: it applies to BAe 146 aeroplanes fitted with Servo-Valve assemblies P/N 3799H1 incorporating Servo-Valve P/N 72189 within the serial-number range specified in the Requirement Document (Applicability). The AD mandates action per BAe Service Bulletin 27-133 by 30 June 1993 (Requirement, Compliance). There is no indication in the text that the instrument’s scope has been altered from its original content."},"complexity_factors":["Technical specificity limited to part numbers and serial-number range (Applicability) — requires technical matching of parts to aircraft.","Mandatory cross-reference to an external technical document (BAe Service Bulletin 27-133) for the actual procedure (Requirement).","Fixed compliance deadline creates scheduling and logistical considerations for operators (Compliance).","Applicability depends on a Requirement Document for serial-number ranges, so the AD is not fully self-contained (Applicability, Requirement).","Reference to related foreign ADs for background/confirmation but no additional procedural complexity (Note)."],"plain_english_summary":"This AD mandates that operators of BAe 146 aeroplanes fitted with specified Servo‑Valve assemblies (including Abex P/N 72189 in a stated serial‑number range) carry out the work detailed in BAe Service Bulletin 27‑133 to inspect/rectify a potentially fractured airbrake feedback spring. It’s compulsory, must be completed by 30 June 1993, and affects operators’ maintenance planning, parts costs and aircraft downtime."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-45-airbrake-feedback-spring","history":"/api/acts/ad-bae-146-45-airbrake-feedback-spring/history","analysis":"/api/acts/ad-bae-146-45-airbrake-feedback-spring/analysis","conflicts":"/api/acts/ad-bae-146-45-airbrake-feedback-spring/conflicts","importantCases":"/api/acts/ad-bae-146-45-airbrake-feedback-spring/important-cases","documents":"/api/acts/ad-bae-146-45-airbrake-feedback-spring/documents"}}