{"id":"F2006B03466","name":"AD/BAe 146/12 Amdt 1 - Elevator `G Weight Damper","slug":"ad-bae-146-12-amdt-1-elevator-g-weight-damper","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43020,"registerId":"commonwealth-F2006B03466-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/12 Amdt 1 - Elevator `G Weight Damper","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 146/12\n\nAmdt 1\n\n\nElevator `G’ Weight Damper 6/89\n\n \n\nApplicability: All models with S/Nos referenced in the Requirement document. Requirement: Action in accordance with BAe SB 27-77-00955 A & C Rev 2. Compliance:               Prior to 30 September 1989.\n\nBackground: This AD contains two concurrent modifications. One to overcome control column oscillation at 2.5 Hz and the other to increase stick centring force following an autopilot cutout. Amendment 1 requires additional work, includes other series aircraft and includes variations dependent on modification state.\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":3,"scope_assessment":{"changed":true,"description":"The original AD appears to have been narrower in scope. Amendment 1 explicitly expands coverage to 'other series aircraft' (broader applicability) and introduces 'variations dependent on modification state' (conditional requirements based on aircraft configuration). This represents mission creep from a targeted fix to a more comprehensive retrofit program."},"complexity_factors":["Very short document (approximately 200 words)","Only 1 defined term implicitly referenced (the Service Bulletin)","No nested legislative cross-references to other Acts or Regulations","Simple conditional logic: applicability limited to specific serial numbers and modification states","Single compliance action with clear deadline","Technical complexity is externalised to the referenced Service Bulletin rather than contained in the legislative instrument itself"],"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:**\nThis directive requires owners and operators of **British Aerospace BAe 146 series aircraft** to make specific modifications to the elevator (the control surface that makes the plane pitch up and down). The changes involve installing or adjusting something called a \"'G' Weight Damper\" — a device that helps stabilise the aircraft's controls.\n\n**Why it's needed:**\nThere were two safety problems identified:\n- The control column (the pilot's yoke/stick) was vibrating or oscillating at a specific frequency (2.5 Hz), which could affect control\n- When the autopilot suddenly disconnected, the control stick wasn't returning to centre strongly enough, potentially causing handling issues\n\n**What must be done:**\nOperators must follow the instructions in **BAe Service Bulletin 27-77-00955 A & C Revision 2** — a technical document from the manufacturer detailing the exact repairs or modifications needed. This \"Amendment 1\" expands the original order to cover more aircraft models and requires additional work depending on what modifications the aircraft already has.\n\n**Who it affects:**\nAnyone operating BAe 146 aircraft in Australia with specific serial numbers listed in the requirement document.\n\n**Deadline:**\nThe work had to be completed before **30 September 1989** (this is a historical directive).\n\n**Why it matters:**\nAirworthiness Directives are legally binding. If operators don't comply, they cannot fly the aircraft. This particular directive addressed potentially dangerous flight control issues that could affect aircraft stability and pilot control."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Amendment 1 broadened and changed the original AD’s scope. It requires additional work, includes other series of the BAe 146 beyond the originally named set, and creates variations in required actions depending on each aircraft’s current modification state (Background). These changes expand the population of affected aircraft and introduce per‑aircraft variability in the work to be done, compared with the original AD."},"complexity_factors":["Technical aviation engineering content requiring adherence to a specific manufacturer service bulletin (Requirement).","Applicability limited to listed serial numbers, requiring operators to check aircraft records (Applicability).","Amendment 1 increases complexity by adding additional work, extending applicability to other series, and introducing variations depending on existing modification state (Background).","Fixed compliance deadline creates operational scheduling and logistical complexity (Compliance).","Dependence on external document (the SB) for procedural detail rather than inclusion in the AD itself."],"plain_english_summary":"This AD requires operators of specified BAe 146 aircraft to carry out two mandated elevator/control modifications per BAe Service Bulletin 27‑77‑00955 A & C Rev 2, to eliminate a 2.5 Hz control‑column oscillation and increase stick‑centring force after autopilot cutout. Compliance (per the SB) is mandatory by 30 September 1989; operators bear parts, labour and downtime costs and must schedule the work with approved maintenance providers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-12-amdt-1-elevator-g-weight-damper","history":"/api/acts/ad-bae-146-12-amdt-1-elevator-g-weight-damper/history","analysis":"/api/acts/ad-bae-146-12-amdt-1-elevator-g-weight-damper/analysis","conflicts":"/api/acts/ad-bae-146-12-amdt-1-elevator-g-weight-damper/conflicts","importantCases":"/api/acts/ad-bae-146-12-amdt-1-elevator-g-weight-damper/important-cases","documents":"/api/acts/ad-bae-146-12-amdt-1-elevator-g-weight-damper/documents"}}