{"id":"F2006B02757","name":"AD/B727/55 Amdt 1 - Main Landing Gear Uplock and Downlock - Inspection and Modification","slug":"ad-b727-55-amdt-1-main-landing-gear-uplock-and-downlock-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42099,"registerId":"commonwealth-F2006B02757-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/55 Amdt 1 - Main Landing Gear Uplock and Downlock - Inspection and Modification","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)  Boeing 727 Series Aeroplanes\n\n \n\nAD/B727/55\n\nAmdt 1\n\n\nMain Landing Gear Uplock and Downlock - Inspection and Modification\n\n\n5/67\n\n \n\nApplicability: All models.\n\n \n\nDocument: Boeing SB No. 32-123, Rev. 4. Compliance: Forthwith.\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\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 standard, narrow airworthiness directive focused on a specific technical issue (landing gear locks) on a specific aircraft type (Boeing 727). It has not expanded beyond its original safety purpose. The 'Amdt 1' indicates this is an amendment to a previous directive, likely updating the reference document (Boeing SB revision) or applicability, but the core scope remains unchanged."},"complexity_factors":["Extremely short document (approximately 150 words)","No defined terms section — uses plain aviation terminology","No conditional logic or nested exceptions","Single, unambiguous compliance requirement ('forthwith')","References only one external document (Boeing SB 32-123 Rev. 4)","No cross-references to other legislation or regulations beyond the enabling CAR 1998 Part 39","Straightforward applicability ('All models') with no exclusions or carve-outs"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific maintenance actions on Boeing 727 aircraft.\n\n**What it does:**\n- **Requires inspection and modification** of the **main landing gear uplock and downlock mechanisms** on all Boeing 727 series aeroplanes.\n- These locks are critical safety components that hold the landing gear in the correct position (up when retracted, down when extended for landing).\n\n**Who it affects:**\n- **All operators** of Boeing 727 aircraft in Australia (the directive applies to \"all models\" of the 727 series).\n- **Maintenance organisations** responsible for servicing these aircraft.\n\n**Why it matters:**\n- Landing gear failures can be catastrophic. Faulty uplocks or downlocks could cause:\n  - Gear collapse on landing (if downlock fails)\n  - Gear failing to stay retracted in flight (if uplock fails), causing drag, fuel burn, or potential damage\n- The directive mandates compliance **\"forthwith\"** (immediately), indicating this addresses an urgent or serious safety concern.\n- Operators must follow **Boeing Service Bulletin No. 32-123, Revision 4** — the manufacturer's official instructions for fixing this problem.\n\n**In short:** If you fly, own, or maintain a Boeing 727 in Australia, you must immediately inspect and modify the main landing gear locking mechanisms according to Boeing's specified procedure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument is labeled as Amendment 1, but the supplied text does not include the original AD language or a comparison to prior scope. On the face of the supplied text, the AD applies to all Boeing 727 models and mandates compliance with Boeing SB No. 32-123 Rev. 4 forthwith; there is no information in the provided material to confirm a change in scope from the original instrument."},"complexity_factors":["Reference to an external technical document (Boeing SB No. 32-123 Rev. 4) — requires obtaining and interpreting that bulletin to know precise actions.","Applicability to all models — increases operational scope and number of affected operators.","Immediate compliance requirement (\"forthwith\") — compresses scheduling and supply-chain flexibility for parts and labour.","Lack of technical detail in the AD text itself — implementation depends on the content of the referenced service bulletin and any accompanying regulatory guidance.","Potential operational impacts (aircraft downtime) that vary by operator size and fleet utilization, adding variability to cost estimation."],"plain_english_summary":"This airworthiness directive requires all Boeing 727 operators to immediately inspect and, where needed, modify the main landing gear uplock and downlock systems per Boeing Service Bulletin 32-123, Revision 4. It is mandatory and binding: operators must follow the SB forthwith, bear the cost and downtime, and may have affected aircraft grounded until work is done. The AD addresses a landing-gear airworthiness concern by forcing prompt compliance with Boeing’s corrective procedures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-55-amdt-1-main-landing-gear-uplock-and-downlock-inspection-and-modification","history":"/api/acts/ad-b727-55-amdt-1-main-landing-gear-uplock-and-downlock-inspection-and-modification/history","analysis":"/api/acts/ad-b727-55-amdt-1-main-landing-gear-uplock-and-downlock-inspection-and-modification/analysis","conflicts":"/api/acts/ad-b727-55-amdt-1-main-landing-gear-uplock-and-downlock-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-b727-55-amdt-1-main-landing-gear-uplock-and-downlock-inspection-and-modification/important-cases","documents":"/api/acts/ad-b727-55-amdt-1-main-landing-gear-uplock-and-downlock-inspection-and-modification/documents"}}