{"id":"F2006B02774","name":"AD/B727/71 - Outboard Aileron Tab Mast Fitting - Inspection and Modification","slug":"ad-b727-71-outboard-aileron-tab-mast-fitting-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42116,"registerId":"commonwealth-F2006B02774-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/71 - Outboard Aileron Tab Mast Fitting - 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\n# AD/B727/71  Outboard Aileron Tab Mast Fitting - Inspection and Modification\n\nApplicability: All models with S/Nos. as detailed in SB No. 57-137. Document:  1. Boeing SB No. 727-57-137, Rev. 2; or\n\n2. FAA AD 75-20-09, Amdt. 39-2375.\n\n# 11/75\n\n \n\nCompliance: 1. Inspect: Initially within 500 hours time in service after 28 November 1975 unless already accomplished, and thereafter at intervals not exceeding 1500 hours time in service until modified by replacement of all blind rivets with bolts and nut-plates in accordance with document 1.\n\n \n\n2. Modify: Before 1 July 1977.\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, single-issue airworthiness directive from 1975 addressing a specific mechanical defect. It has not expanded beyond its original purpose of ensuring the structural integrity of the aileron tab mast fitting on Boeing 727 aircraft."},"complexity_factors":["Single, specific technical requirement (one aircraft part on one aircraft series)","Only two compliance actions required (inspect and modify)","Clear deadlines and intervals specified","Minimal cross-referencing (only to Boeing Service Bulletin and FAA AD)","No nested exceptions or conditional logic","Short document (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific Boeing 727 aircraft.\n\n**What it does:**\n- Requires owners/operators of certain Boeing 727 planes to **inspect** and **modify** a specific part called the \"outboard aileron tab mast fitting\" — a component that helps control the aircraft's roll during flight.\n\n**Who it affects:**\n- All Boeing 727 models with specific serial numbers listed in Boeing Service Bulletin 57-137.\n\n**What must be done:**\n- **Inspection:** Check the fitting within 500 flight hours after 28 November 1975 (if not already done), then re-inspect every 1,500 flight hours until the modification is complete.\n- **Modification:** Replace all blind rivets with bolts and nut-plates by 1 July 1977, following Boeing's technical instructions.\n\n**Why it matters:**\nAirworthiness Directives are legally enforceable safety fixes. This one addresses a potential structural failure risk in the aileron control system. Non-compliance means the aircraft cannot legally fly in Australian airspace."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument, as presented, specifies a targeted inspection and retrofit programme for aircraft listed in Boeing SB No. 57-137 and sets fixed inspection intervals and a modification deadline. There is no indication in the text that the scope has been expanded or narrowed relative to its apparent original purpose; it remains limited to the serial numbers identified and to the inspection-and-replace remedy described (see \"Applicability\" and \"Compliance\")."},"complexity_factors":["Narrow, serial-number-limited applicability requiring consultation of Boeing SB No. 57-137 (Applicability).","Fixed inspection schedule with an initial short-term deadline (within 500 hours after 28 Nov 1975) and recurring intervals (not exceeding 1,500 hours) until modification (Compliance: 1. Inspect).","A firm final modification deadline (before 1 Jul 1977) that ends the inspection requirement once completed (Compliance: 2. Modify).","Technical compliance is tied to external documents (Boeing SB No. 727-57-137 Rev. 2 or FAA AD 75-20-09), creating reliance on those documents for procedural detail (Document: 1./2.).","Operational impacts (parts availability, maintenance resources, and aircraft downtime) influence implementation though they are not specified in the AD text."],"plain_english_summary":"Operators of the Boeing 727s listed in Boeing SB No. 57-137 must inspect the outboard aileron tab mast fitting (initial within 500 hours, then every 1,500 hours until modified) and complete a one‑time modification—replace blind rivets with bolts and nut‑plates per Boeing SB 727‑57‑137 Rev.2 or FAA AD 75‑20‑09—by 1 July 1977. The AD sets the timetable; affected operators pay for inspections, parts, labour and downtime."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-71-outboard-aileron-tab-mast-fitting-inspection-and-modification","history":"/api/acts/ad-b727-71-outboard-aileron-tab-mast-fitting-inspection-and-modification/history","analysis":"/api/acts/ad-b727-71-outboard-aileron-tab-mast-fitting-inspection-and-modification/analysis","conflicts":"/api/acts/ad-b727-71-outboard-aileron-tab-mast-fitting-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-b727-71-outboard-aileron-tab-mast-fitting-inspection-and-modification/important-cases","documents":"/api/acts/ad-b727-71-outboard-aileron-tab-mast-fitting-inspection-and-modification/documents"}}