{"id":"F2006B02655","name":"AD/B727/133 - Inboard TE Flap Inboard Track","slug":"ad-b727-133-inboard-te-flap-inboard-track","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41971,"registerId":"commonwealth-F2006B02655-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/133 - Inboard TE Flap Inboard Track","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/B727/133 Inboard TE Flap Inboard Track 7/91\n\nApplicability: Model 727 series.\n\n \n\nRequirement: Action in accordance with the Technical Requirements of FAA AD 91-09-03 Amdt 39-6968.\n\n \n\nNote: BOEING SB 727-32-340 refers.\n\n \n\nCompliance: As specified in the Requirement Document with a revised effective date of 11 July 1991 for Australian registered aircraft.\n\n \n\nBackground: The FAA has received reports of cracking of the flap tracks. This condition, if not corrected, could result in failure of the flap track and possible separation of the inboard trailing edge flap.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD does not change the population of affected aircraft — it applies to Model 727 series as stated (\"Applicability\"). What the AD does change relative to the referenced Requirement Document is the effective compliance date for Australian-registered aircraft (it specifies a revised effective date of 11 July 1991) rather than expanding or narrowing which aircraft are covered."},"complexity_factors":["Cross-reference to FAA AD 91-09-03 Amdt 39-6968 requires obtaining and applying an external regulatory document for precise technical steps (\"Requirement\").","Dependence on Boeing Service Bulletin 727-32-340 for technical guidance means operators must reconcile the AD with a manufacturer document (\"Note\").","The AD sets a revised effective date for Australian-registered aircraft (11 July 1991), creating a jurisdiction-specific compliance timing requirement (\"Compliance\").","Technical nature of inspections/repairs (flap track cracking) requires specialised maintenance capability and parts, increasing implementation complexity for operators (implied by \"Background\" and \"Requirement\").","Enforcement and verification occur within CASA’s Schedule of Airworthiness Directives framework, so operators must be prepared for regulatory oversight (header/placement)."],"plain_english_summary":"### What this directive does\n\nThis Airworthiness Directive (AD) requires operators of Boeing Model 727 series aeroplanes registered in Australia to carry out the maintenance actions specified in the referenced FAA AD 91-09-03 (Amdt 39-6968). The AD implements those technical requirements for Australian-registered aircraft and sets an effective compliance date of 11 July 1991 for Australia. (See: \"Requirement\" and \"Compliance\".)\n\n### Who it affects\n\n- Owners and operators of Boeing 727 series aeroplanes registered in Australia (\"Applicability\").\n- Maintenance organisations and engineers who will perform the inspections and repairs called for in the referenced FAA AD and Boeing Service Bulletin (\"Note\").\n- The Civil Aviation Safety Authority (CASA) enforces the AD as part of the Schedule of Airworthiness Directives under the Civil Aviation Regulations. (Header text.)\n\n### Why it matters (mechanically)\n\nThe FAA reported cracking in the inboard trailing-edge (TE) flap tracks. The AD requires the actions in FAA AD 91-09-03 because the reported cracking could lead to failure of a flap track and possible separation of the inboard TE flap if not corrected. The AD therefore directs inspection/repair actions to detect and fix cracking before such failure occurs. (See: \"Background\" and \"Requirement\".)\n\n### What operators must do, who decides, and who pays\n\n- Operators must follow the Technical Requirements set out in FAA AD 91-09-03 (as referenced here) and any procedures in Boeing Service Bulletin 727-32-340 that the Requirement Document refers to. (\"Requirement\"; \"Note\").\n- The AD is issued under Australia’s civil aviation framework and is enforceable by the Civil Aviation Safety Authority; compliance is measured against the Requirement Document with the revised effective date for Australian aircraft (11 July 1991). (Header; \"Compliance\").\n- Costs for inspections, repairs, parts, downtime, and labour fall to the aircraft owner/operator and their contracted maintenance providers; the AD itself does not fund those costs (implied by mandatory operator compliance in \"Requirement\" and \"Compliance\").\n\n### Implementation, incentives and trade-offs\n\n- The AD references an external FAA AD and a Boeing Service Bulletin. This means Australian operators must obtain and follow those external documents to meet the AD requirements (\"Requirement\"; \"Note\").\n- The directive changes operational and maintenance priorities for affected aircraft until the specified inspections/repairs are completed: operators will need to schedule work, potentially affecting aircraft availability and short-term operating costs (inferred from mandatory compliance in \"Requirement\" and \"Compliance\").\n- The AD reduces the risk of in-service failure of the inboard TE flap by mandating inspection/repair activity. The AD does not itself specify the detailed inspection steps in this text; it relies on the referenced FAA AD and Boeing Service Bulletin for technical steps (\"Requirement\"; \"Note\").\n\n### Practical points to check when implementing\n\n- Obtain and follow FAA AD 91-09-03 (Amdt 39-6968) and Boeing SB 727-32-340 as they contain the technical instructions cited by this AD (\"Requirement\"; \"Note\").\n- Confirm the revised Australian effective compliance date: 11 July 1991 (\"Compliance\").\n- Ensure maintenance providers document inspections and any corrective actions to demonstrate compliance to CASA if required (enforcement implied by the AD's placement in the Schedule of Airworthiness Directives). (Header.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific airworthiness concern on a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection/repair of flap track cracking."},"complexity_factors":["Very short document (under 200 words)","Only 4 operative paragraphs: Applicability, Requirement, Note, and Compliance","No defined terms section — relies entirely on external documents (FAA AD and Boeing SB)","Single mechanical issue addressed with reference to external technical standards","No conditional logic, exceptions, or nested provisions","Straightforward compliance deadline with no alternative methods or phased implementation"],"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 **Boeing 727 series aircraft** to inspect and fix a specific mechanical problem: **cracking in the inboard trailing edge flap track** (the metal rail that guides the flaps — the movable wing surfaces that help planes slow down for landing).\n\n**Why it matters:**\nIf left unchecked, these cracks could cause the flap track to break completely. That could make the flap fall off during flight, seriously compromising the aircraft's ability to land safely.\n\n**What must be done:**\nAircraft operators must follow the technical instructions in **FAA AD 91-09-03** (the American aviation safety authority's equivalent order), as modified by **Boeing Service Bulletin 727-32-340**. The deadline for Australian-registered planes is **11 July 1991**.\n\n**Who it affects:**\nAnyone operating a Boeing 727 in Australia — typically cargo carriers, charter operators, or older passenger fleets still flying this classic trijet."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-133-inboard-te-flap-inboard-track","history":"/api/acts/ad-b727-133-inboard-te-flap-inboard-track/history","analysis":"/api/acts/ad-b727-133-inboard-te-flap-inboard-track/analysis","conflicts":"/api/acts/ad-b727-133-inboard-te-flap-inboard-track/conflicts","importantCases":"/api/acts/ad-b727-133-inboard-te-flap-inboard-track/important-cases","documents":"/api/acts/ad-b727-133-inboard-te-flap-inboard-track/documents"}}