{"id":"F2006B06775","name":"AD/SA-TP/26 Amdt 1 - Flap Operating System","slug":"ad-sa-tp-26-amdt-1-flap-operating-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114617,"registerId":"commonwealth-F2006B06775-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SA-TP/26 Amdt 1 - Flap Operating System","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 (Scottish Aviation) Twin Pioneer Series Aeroplanes\n\n \n\n# AD/SA-TP/26\n\nAmdt 1\n\nApplicability: All models.\n\n# Flap Operating System 1/87\n\n \n\nRequirement: Action in accordance with Scottish Aviation TNS 50 issue 3.\n\n \n\nCompliance: Within 200 hours time in service after last compliance with the previous issue of this Directive prior to 31 January 1987 and thereafter every 200 hours time in service.\n\n \n\nBackground: This amendment reflects the later issue of the TNS which extends compliance to 200 hours time in service.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This amendment changes the compliance interval by adopting the later issue of Scottish Aviation TNS 50 (issue 3) and setting required actions at 200 hours time in service. The Background expressly states the amendment \"reflects the later issue of the TNS which extends compliance to 200 hours time in service.\" Operationally, that alters the frequency at which operators must perform the flap-system action compared with the previous Directive. (Background; Compliance)"},"complexity_factors":["Cross-reference to an external technical document (Scottish Aviation TNS 50 issue 3) — users must obtain and follow that document to know the exact tasks (Requirement).","Periodic compliance scheduling tied to aircraft time-in-service with a transitional clause linked to a date and previous compliance (within 200 hours after last compliance prior to 31 January 1987, then every 200 hours) — requires recordkeeping and calculation. (Compliance).","Applicability to all models of the Twin Pioneer series simplifies scope but increases the universe of affected operators who must apply the external TNS. (Applicability).","The AD text does not include technical tolerances or alternative compliance routes, so implementation depends on interpretation of the TNS and regulatory enforcement practice. (Requirement)."],"plain_english_summary":"What this directive does (mechanics)\n\n- This Airworthiness Directive (AD) applies to all British Aerospace (Scottish Aviation) Twin Pioneer aeroplanes. (Applicability)\n- It requires operators to carry out the maintenance or inspection actions set out in Scottish Aviation Technical Note/Schedule (TNS) 50 issue 3 for the flap operating system. The AD does not reproduce the technical steps; it mandates compliance with that external TNS. (Requirement)\n- The timing required by this amendment is: perform the TNS action within 200 hours time in service after the last compliance with the previous issue of the Directive (sooner if already scheduled), provided that last compliance was before 31 January 1987, and then repeat the action every 200 hours time in service thereafter. (Compliance)\n\nStated reason and how that changes behaviour\n\n- The AD states it amends the previous Directive to reflect a later issue of the manufacturer’s TNS, which extends the compliance interval to 200 hours time in service. (Background)\n- Mechanically, the AD changes operators’ maintenance schedules: it requires them to perform the flap-system action specified in TNS 50 issue 3 at 200-hour intervals rather than at whatever interval the earlier Directive required. (Requirement; Compliance)\n\nWho pays, who decides, and who acts\n\n- Aircraft owners/operators bear the direct costs and operational effects: they must arrange for the TNS-specified action to be performed at the required intervals and keep time-in-service records to demonstrate compliance. (Requirement; Compliance)\n- The Civil Aviation Safety Authority implements and enforces the AD by issuing it; the AD, in turn, delegates the technical content to Scottish Aviation’s TNS 50 issue 3, so the manufacturer’s document determines the exact tasks. (Requirement)\n- Maintenance organisations or certificated personnel must carry out the actions described in the referenced TNS and log compliance. (Requirement)\n\nPractical implications, trade-offs and implementation issues (source-grounded)\n\n- Compliance burden: Operators must track flight hours and schedule the TNS action every 200 hours; this creates recurring maintenance work and potential aircraft downtime. (Compliance)\n- Cost/incentive effects: Extending the interval to 200 hours (as stated in the Background) reduces the frequency of required interventions compared with the earlier requirement, which lowers the periodic administrative and labour cost per unit time but concentrates required work into fewer events. (Background; Compliance)\n- Reliance on external document: The AD requires action “in accordance with Scottish Aviation TNS 50 issue 3” rather than specifying steps itself, so understanding and fulfilling the AD requires access to and interpretation of that manufacturer document. That shifts technical discretion to the TNS and to the maintenance organisations that apply it. (Requirement)\n- Implementation risk and recordkeeping: Demonstrating compliance depends on accurate time-in-service records and completion evidence for the TNS action; failure to keep or produce those records would be the main compliance exposure. (Compliance)\n- Limited discretion in the AD text: The AD prescribes the interval and the external reference but does not set alternative compliance methods or tolerances; any variation would require separate approval or another regulatory instrument. (Requirement; Compliance)\n\nNet operational effect (concise)\n\n- Operators of Twin Pioneer aeroplanes must follow Scottish Aviation TNS 50 issue 3 for the flap operating system and schedule that work every 200 hours time in service (with the initial 200-hour deadline described above). The amendment’s stated effect is to adopt the manufacturer’s later instruction and to standardise a 200-hour compliance interval. (Requirement; Compliance; Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment does not expand the scope beyond the original directive. It merely updates the compliance interval (time between inspections) based on a revised technical notice. The subject matter (flap operating system on Twin Pioneer aircraft) and the affected fleet remain identical to the original AD/SA-TP/26."},"complexity_factors":["Very short document (approximately 200 words)","Only 1 defined term implicitly referenced (TNS 50 — a technical notice)","Single, clear compliance requirement with straightforward time-based trigger","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1988","Simple amendment: only changes the compliance interval from an unspecified shorter period to 200 hours","No conditional logic, exceptions, or nested provisions"],"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). Think of it like a compulsory recall notice, but for aircraft rather than cars.\n\n**What it does:** It requires owners and operators of **British Aerospace (Scottish Aviation) Twin Pioneer aeroplanes** (all models) to inspect and maintain the **flap operating system** — the machinery that controls the flaps on the wings. Flaps are the movable surfaces that extend during takeoff and landing to provide extra lift at low speeds.\n\n**The specific requirement:** Operators must follow the instructions in a technical document called **Scottish Aviation TNS 50, Issue 3**. This involves checking the flap system and fixing any problems found.\n\n**When to do it:** \n- First check: Within **200 hours of flying time** after the last time you complied with the previous version of this directive, provided that previous compliance happened before 31 January 1987.\n- Ongoing: **Every 200 hours of flying time** after that.\n\n**Why it matters:** The flaps are critical for safe takeoffs and landings. If they fail, the aircraft could crash. This directive was updated (Amendment 1) to extend the allowed time between inspections from a shorter period to 200 hours, giving operators more flexibility while maintaining safety.\n\n**Who it affects:** Anyone who owns, operates, or maintains a Scottish Aviation Twin Pioneer aircraft in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sa-tp-26-amdt-1-flap-operating-system","history":"/api/acts/ad-sa-tp-26-amdt-1-flap-operating-system/history","analysis":"/api/acts/ad-sa-tp-26-amdt-1-flap-operating-system/analysis","conflicts":"/api/acts/ad-sa-tp-26-amdt-1-flap-operating-system/conflicts","importantCases":"/api/acts/ad-sa-tp-26-amdt-1-flap-operating-system/important-cases","documents":"/api/acts/ad-sa-tp-26-amdt-1-flap-operating-system/documents"}}