{"id":"F2006B09245","name":"AD/DHC-8/86 - Wing De-icing Boot Patch Limits","slug":"ad-dhc-8-86-wing-de-icing-boot-patch-limits","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53155,"registerId":"commonwealth-F2006B09245-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)\n\nBombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/DHC-8/86 Wing De-icing Boot Patch Lim","sectionType":"part","heading":"AD/DHC-8/86 Wing De-icing Boot Patch Limits 4/2002","content":"# AD/DHC-8/86 Wing De-icing Boot Patch Limits 4/2002\n\nApplicability: Model DHC-8 aeroplanes, series 100, 200 and 300.\n\nRequirement: 1. Carry out a visual inspection of the wing leading edge de-icer boots to assess compliance with repair patch limits for the critical zone published in Bombardier Aircraft Maintenance Manuals:\n\nSeries 100: PSM 1-8-2, Revision 49, dated 3 October 2001; Chapter 30- 10-48\n\nSeries 200: PSM 1-82-2, Revision 11, dated 19 October 2001; Chapter 30-12-00\n\nSeries 300: PSM 1-83-2, TR 30-21, dated 30 October 2001; Chapter 30-10-48\n\n    2. For those aeroplanes with wing de-icer boots which exceed the patch size and/or number limits in the critical zone, identified during the inspection at Requirement 1, insert a copy of this Airworthiness Directive in the Aircraft Flight Manual (AFM) advising flight crews of the performance penalties detailed in the following table:\n\n| AFM Sections               | Note: | AFM Limits With De-Ice Boot Patch Limits ExceededFlap settings as applicable to aircraft model. |\n| -------------------------- | ----- | ----------------------------------------------------------------------------------------------- |\n| T/O Speed: Sub-Section 5-2 |       |                                                                                                 |\n| V1, Vr & V2                | Add:  |                                                                                                 |\n|                            | 5 kt  | (flap 0°)                                                                                       |\n|                            | 5 kt  | (flap 5°)                                                                                       |\n|                            | 5 kt  | (flap 10°)                                                                                      |\n|                            | 5 kt  | (flap 15°)                                                                                      |\n|                            | Add:  |                                                                                                 |\n| Final T/O Climb Speed      |       |                                                                                                 |\n|                            | 5 kt  | (flap 0°)                                                                                       |","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing specific maintenance limits for de-icing boots on DHC-8 aircraft. It has not expanded beyond this technical airworthiness issue."},"complexity_factors":["Short, single-purpose directive with only 2 requirements","References specific technical manuals (PSM 1-8-2, PSM 1-82-2, PSM 1-83-2) but does not reproduce their content","Simple conditional logic: 'if patches exceed limits, then insert AFM notice'","Single table with straightforward speed adjustments (uniform 5 kt addition)","No nested exceptions or complex cross-referencing within the instrument itself","Limited defined terms (only 'critical zone' implied, not explicitly defined in text)"],"plain_english_summary":"This CASA safety order for Bombardier DHC‑8 Series 100/200/300 targets worn or over‑patched wing de‑icing boots. Operators must inspect boots for repairs that exceed the manufacturer’s size/number limits in the critical zone.\n\nIf limits are exceeded, an Aircraft Flight Manual note must be inserted requiring takeoff speeds be increased by 5 knots (all flap settings). It affects Australian owners/operators and preserves takeoff safety until boots are repaired or replaced."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD remains tightly focused on the single technical issue of wing leading‑edge de‑icer boot repair patch limits for DHC‑8 series 100/200/300 aeroplanes. It requires inspection against manufacturer limits and, if limits are exceeded, an AFM amendment to notify crews of specified performance penalties. There is no indication in the text provided that the AD expands beyond that original safety objective; it does not add unrelated regulatory burdens or broader operational controls."},"complexity_factors":["Applies to three aircraft series (DHC‑8 series 100, 200, 300) with distinct AMM references per series","References three specific AMM documents with revision dates and chapter numbers (cross‑reference to manufacturer material)","Two sequential requirements: (1) inspection; (2) conditional AFM insertion if limits exceeded","Conditional logic (AFM insertion only if patch limits exceeded)","Operational mitigation expressed as a small table of amended V‑speeds (formatting in the AD extract is compact/partly ambiguous)","Relies on an external compliance section (timing not included in the extract)"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Applies to Bombardier (De Havilland) DHC-8 series 100, 200 and 300 aeroplanes. (Applicability)\n- Requires a visual inspection of the wing leading-edge de‑icer boots to check whether any repair patches in the aircraft’s critical zone exceed the size or number limits set out in the applicable Bombardier Aircraft Maintenance Manual (AMM) chapters and revisions listed in the AD. (Requirement 1)\n- If an aeroplane is found to have de‑icer boot patches that exceed those patch‑size/number limits, the operator must insert a copy of this Airworthiness Directive into the Aircraft Flight Manual (AFM) so flight crews are informed of the specified performance penalties (changes to take‑off speeds and final take‑off climb speed). (Requirement 2 and the AFM table)\n- The AD is issued under the CASA delegate’s regulatory power and must be complied with in the circumstances, manner and at the times set out in the AD’s compliance section (the compliance timing is set by the AD; that section is referenced but not reproduced in the extract you provided).\n\n**Who is affected**\n\n- Primary duty is on operators/owners of DHC‑8 series 100/200/300 aeroplanes: they must carry out the inspection, compare repairs against the AMM limits, and, if limits are exceeded, amend the AFM by inserting the AD so flight crews are notified.\n- Flight crews are affected operationally if an aircraft has excessive patches: they must follow the amended AFM limits (the AD states added take‑off speed values — see table).\n- Maintenance organisations and engineers are indirectly affected because they must inspect to the AMM references listed and certify airworthiness accordingly.\n\n**Why it matters (official rationale and the mechanics of trade‑offs)**\n\n- The stated safety objective is to correct an unsafe condition associated with de‑icer boot repairs on the wing leading edge. The AD relies on Bombardier AMM repair‑limit data and requires inspection to confirm compliance. (Background/rationale is referenced by the AD; the extract provided gives the remedial steps.)\n\n- Mechanically, the control is twofold: (a) an inspection requirement to detect non‑conforming repairs, and (b) an operational mitigation for affected aircraft — amendments to AFM performance data so flight crews operate with changed take‑off/climb speeds. The AD therefore trades a detection/administrative burden for an operational restriction where non‑conformance exists.\n\n**Who pays and who decides**\n\n- Operators pay: inspection labour, possible follow‑up maintenance if repairs exceed limits, administrative cost of updating AFMs, and operational costs if the AFM‑prescribed performance penalties constrain payload, fuel, or runway requirements. (Requirement 1–2)\n- CASA (via the delegate) decides the legal requirement and the compliance timetable; Bombardier’s AMM provides the technical thresholds that trigger the operational restriction. (AD issuance clause; Requirement 1 references specific AMM revisions.)\n\n**Behavioural effects and practical implications**\n\n- Maintenance behaviour: operators will need to inspect de‑icer boots against the AMM limits and may need to repair or replace boots that have excessive patches.\n- Operational behaviour: for aircraft that fail the inspection, flight crews must use amended AFM speeds—this typically increases take‑off/climb V‑speeds by the amounts listed, which can increase take‑off distance required or force weight/fuel/route changes.\n\n**Implementation, compliance and risk notes**\n\n- The AD references specific AMM documents and revision dates (different for series 100, 200 and 300). Operators must use the exact chapters/revisions listed to determine whether a repair exceeds limits (Requirement 1).\n- The AD’s mitigation is procedural (insert AD in AFM) rather than mandating immediate repair or grounding; that leaves market actors to decide whether to accept the AFM penalties operationally or to carry out corrective maintenance to restore AMM compliance.\n- There is an implementation risk if the AFM amendment is not clearly integrated into crew training/dispatch procedures; the AD places the onus on operators to ensure flight crews are aware of the changed speeds.\n\n**Source‑stated purpose vs. trade‑offs**\n\n- The AD presents its purpose as correcting an unsafe condition (as set out in the background). That purpose is achieved by detecting non‑conforming de‑icer repairs and imposing AFM performance limits in affected aeroplanes. The concrete trade‑offs are: inspection and possible repair costs for operators, and operational penalties (higher V‑speeds, possible payload/runway impacts) if repairs are left in place and the AFM is amended instead of repairing.\n\n(References within the AD: Requirement 1 lists the exact AMM PSM/TR document numbers and revision dates per series; Requirement 2 and the AFM table set out the operational action.)"},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-86-wing-de-icing-boot-patch-limits","history":"/api/acts/ad-dhc-8-86-wing-de-icing-boot-patch-limits/history","analysis":"/api/acts/ad-dhc-8-86-wing-de-icing-boot-patch-limits/analysis","conflicts":"/api/acts/ad-dhc-8-86-wing-de-icing-boot-patch-limits/conflicts","importantCases":"/api/acts/ad-dhc-8-86-wing-de-icing-boot-patch-limits/important-cases","documents":"/api/acts/ad-dhc-8-86-wing-de-icing-boot-patch-limits/documents"}}