{"id":"F2006B06267","name":"AD/PL 12/20 Amdt 3 - Main Wing and Stub Wing Fatigue Life Limitation","slug":"ad-pl-12-20-amdt-3-main-wing-and-stub-wing-fatigue-life-limitation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47277,"registerId":"commonwealth-F2006B06267-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"RETIREMENT SCHEDULE","sectionType":"part","heading":"RETIREMENT SCHEDULE","content":"# RETIREMENT SCHEDULE\n\n|                                                                                                     | PL12, PL12U, PL12/T300, PL12/T300A, PL12/T320 | PL12/T400   |\n| --------------------------------------------------------------------------------------------------- | --------------------------------------------- | ----------- |\n| MAIN WING                                                                                           | 11700 hours                                   | 10600 hours |\n| STUB WING                                                                                           | 8700 hours                                    | 11400 hours |\n| Aluminium stub wing extension                                                                       |                                               |             |\n| - S/Nos H1107, H5114 toH5117 not fitted with Mod 155                                                | NA                                            | 3780 hours  |\n| - S/Nos after H5117, and the above S/Nos when fitted with Mod 155 before 1500 hours time in service | NA                                            | 11400 hours |\n\nCompliance: Forthwith.\n\nThis Amendment becomes effective on 5 August 2004.","sortOrder":0},{"sectionNumber":"Transavia PL 12 Series Aeroplanes","sectionType":"part","heading":"Transavia PL 12 Series Aeroplanes","content":"# Transavia PL 12 Series Aeroplanes\n\nAD/PL 12/20 Amdt 3 (continued)\n\nBackground: The manufacturer has carried out fatigue life evaluations which have established the above fatigue life limitations.\n\nAmendment 1 was raised to include the model PL 12/T400. Amendment 2 corrected some transcription errors.\n\nAmendment 3 corrects a typographical error.\n\n![Signature of James Coyne, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 25 June 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 14 July 2004.","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"This version expanded the instrument's scope relative to the original by adding the PL12/T400 model (Amendment 1) and by specifying separate retirement hours for that model's main and stub wing. It also introduced a differentiated limit for the aluminium stub wing extension tied to serial numbers and to whether Mod 155 was fitted before 1,500 hours TIS (creating a compliance pathway that changes the effective life limit). Subsequent amendments corrected transcription/typographical errors but did not further broaden the set of models or substantive limits."},"complexity_factors":["Short, single-table retirement schedule with a small number of numeric limits (about 6–8 discrete limits/conditions).","One conditional rule tied to serial-number ranges and whether Mod 155 was fitted before 1,500 hours time-in-service.","No dense cross-references to other statutory provisions or external documents in the instrument text itself.","Few defined terms and minimal nested exceptions (only the Mod 155 / serial-number condition).","Amendment history noted (3 amendments) but only one amendment materially broadened scope (addition of PL12/T400); later amendments were transcription/typographical corrections."],"plain_english_summary":"**What this instrument does (mechanically):**\n\n- It imposes mandatory retirement (fixed flight-hour life) limits on the main wing and the stub wing of specific Transavia PL‑12 series aeroplanes. The retirement limits are expressed in hours-in-service and are listed in the Retirement Schedule table. (See the Retirement Schedule table in the instrument.)\n- The limits apply immediately (\"Compliance: Forthwith\") and the Amendment is recorded as effective 5 August 2004.\n- For the PL12, PL12U, PL12/T300, PL12/T300A and PL12/T320 group the limits are: main wing 11,700 hours and stub wing 8,700 hours.\n- For the PL12/T400 the limits are: main wing 10,600 hours and stub wing 11,400 hours.\n- There is an additional, specific set of limits for the aluminium stub wing extension on PL12/T400 aircraft depending on serial number and whether Mod 155 has been fitted before 1,500 hours time-in-service: certain serial numbers not fitted with Mod 155 are limited to 3,780 hours; later serial numbers or aircraft fitted with Mod 155 before 1,500 hours are allowed 11,400 hours. (See the two-line conditional entries under \"Aluminium stub wing extension\" in the table.)\n\n**Who is affected:**\n\n- Owners and operators of Transavia PL‑12 series aeroplanes (the models listed in the Retirement Schedule). They must retire the specified wing components from service once the listed hours are reached.\n- Maintenance organisations, engineers and parts suppliers who service, modify or replace those wing components.\n\n**Why it matters (source claim and immediate consequence):**\n\n- The manufacturer performed fatigue life evaluations and, based on those results, established these component life limits. The instrument records that background claim and then requires compliance with the limits.\n- Practically, affected aircraft will need parts replacement or component retirement when those hour limits are reached. Operators will need to track serial numbers, modification status (Mod 155), and time-in-service to determine applicable limits.\n\n**Costs, incentives and operational trade-offs (mechanical effects):**\n\n- Who pays: aircraft owners/operators bear the direct costs — removing wings or extensions from service, replacing components, performing modifications (Mod 155) if chosen, and any associated downtime.\n- Incentives created: because fitting Mod 155 before 1,500 hours TIS changes the applicable retirement limit for certain stub‑wing extensions (from 3,780 to 11,400 hours), there is a clear incentive for affected owners to install that modification early to obtain the longer life limit. That creates a trade-off: pay the modification cost upfront in exchange for extending component life and deferring replacement costs.\n- Behavioural change required: operators must (a) maintain and consult accurate records of aircraft serial numbers and modification status, (b) plan component replacements around the stated hours limits, and (c) decide whether to install Mod 155 early where eligible.\n\n**Implementation, compliance burden and risks:**\n\n- Administrative burden: record-keeping to demonstrate compliance (hours tracking, Mod 155 fitment records), and ensuring maintenance schedules align with retirement times.\n- Technical/operational risk: if an operator misunderstands the serial-number/Mod-155 condition, they could apply the wrong retirement limit. The AD creates a requirement that is relatively simple to verify but hinges on accurate historical modification and hours records.\n- Market effects on operators: smaller operators with limited spares or less capital may face higher relative disruption from component retirement than larger operators who can absorb or spread those costs.\n\n**Concrete effects on private choice and the supply side:**\n\n- Operators can choose between (a) early modification (Mod 155) where that yields a longer life, (b) planning for earlier retirement/replacement if not modified, or (c) withdrawing an aircraft from service if replacement/modification is not economical.\n- Parts suppliers and maintenance organisations may see concentrated demand for the Mod 155 kit and for replacement stub/main wing components around retirement horizons.\n\n**Source claim and assessment:**\n\n- The instrument records the manufacturer's claim that fatigue testing justifies these limits. Mechanically, the AD converts that technical assessment into a legally mandatory retirement schedule (the table). The AD does not itself contain the fatigue data or a safety analysis beyond that statement — compliance is required because the national regulator has recorded and enacted the limits.\n\n(References in the instrument: the Retirement Schedule table; \"Compliance: Forthwith\"; the note that the limits are based on manufacturer fatigue evaluations.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is Amendment 3 to an existing Airworthiness Directive. The amendments have remained tightly focused on the original purpose: establishing fatigue life limits for wing components. Amendment 1 added the PL 12/T400 model, Amendment 2 corrected transcription errors, and Amendment 3 fixed a typographical error. The scope has not expanded beyond fatigue life limitations for these specific aircraft components."},"complexity_factors":["Very short document (under 300 words)","Only 3 defined aircraft components subject to limits (main wing, stub wing, aluminium stub wing extension)","Simple tabular format for retirement schedule","Limited conditional logic — only one exception based on serial number range and modification status (Mod 155)","No cross-references to other legislation or regulations","Single compliance requirement ('Forthwith') with no alternative methods of compliance","Narrow scope — applies only to specific Transavia PL-12 series aircraft models"],"plain_english_summary":"This CASA Airworthiness Directive requires immediate tracking and retirement of specific structural parts on Transavia PL-12 series agricultural aircraft after set flight-hour limits to prevent metal-fatigue failures.  \n\nIt affects owners/operators of PL-12, PL-12U, PL-12/T300, PL-12/T300A, PL-12/T320 and PL-12/T400 types (farmers, contractors, schools). Exceeding the prescribed hours—particularly for main and stub wings and certain aluminium stub extensions—means the parts must be permanently removed from service."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pl-12-20-amdt-3-main-wing-and-stub-wing-fatigue-life-limitation","history":"/api/acts/ad-pl-12-20-amdt-3-main-wing-and-stub-wing-fatigue-life-limitation/history","analysis":"/api/acts/ad-pl-12-20-amdt-3-main-wing-and-stub-wing-fatigue-life-limitation/analysis","conflicts":"/api/acts/ad-pl-12-20-amdt-3-main-wing-and-stub-wing-fatigue-life-limitation/conflicts","importantCases":"/api/acts/ad-pl-12-20-amdt-3-main-wing-and-stub-wing-fatigue-life-limitation/important-cases","documents":"/api/acts/ad-pl-12-20-amdt-3-main-wing-and-stub-wing-fatigue-life-limitation/documents"}}