{"id":"F2006B07229","name":"AD/SWSA226/87 - Operation of Deicing Boots","slug":"ad-swsa226-87-operation-of-deicing-boots","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49048,"registerId":"commonwealth-F2006B07229-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \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.","sortOrder":0},{"sectionNumber":"AD/SWSA226/87 Operation of Deicing Boots","sectionType":"part","heading":"AD/SWSA226/87 Operation of Deicing Boots 7/2000","content":"# AD/SWSA226/87 Operation of Deicing Boots 7/2000\n\nApplicability: All models SA226-T, SA226-AT, SA226-T(B), SA227-AT, SA227-TT, SA226-TC,\n\nSA227-AC, SA227-PC, SA227-BC, SA227-CC and SA227-DC aircraft equipped with pneumatic deicing boots.\n\nRequirement: Revise the Limitations Section of the aircraft's Aircraft Flight Manual (AFM) by incorporating the following:\n\n\" Except for certain phases of flight where the AFM specifies that deicing boots should not be used (e.g., take-off, final approach, and landing), compliance with the following is required.\n\n    Wing and Tail Leading Edge Pneumatic Deicing Boot System, if installed, must be activated:\n\n    \\- At the first sign of ice formation anywhere on the aircraft, or upon annunciation from an ice detector system, whichever occurs first; and\n\n    \\- The system must either be continued to be operated in the automatic cycling mode, if available; or the system must be manually cycled as needed to minimize the ice accretions on the airframe.\n\n    The wing and tail leading edge pneumatic deicing boot system may be deactivated only after:\n\n    \\- Leaving known or observed/detected icing that the flight crew has visually observed on the aircraft or was identified by the on-board sensors; and\n\n    \\- After the airplane is determined to be clear of ice.\"\n\nAlternatively, a copy of this Directive may be inserted in the Limitations Section of the Aircraft Flight Manual preceding the paragraph covering Operation in Icing Conditions.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD stays within the original narrow safety objective: it clarifies and mandates pilot operating procedure for pneumatic deicing boots on specified SA226/SA227 models. It does not broaden scope into maintenance mandates, hardware modifications, or additional aircraft types, so it has not meaningfully changed scope beyond that original purpose."},"complexity_factors":["Short, single-issue directive concentrated on AFM text revision","Applicability limited to a specific list of SA226/SA227 models (11 variants listed)","No extensive defined-terms or long interpretation section","One main conditional logic: activate at first sign of ice or upon ice-detector annunciation","Minor exceptions referenced (AFM-specified phases where boots must not be used)","Some operational ambiguity in phrases like “first sign of ice” and “determined to be clear of ice”"],"plain_english_summary":"**What this directive changes (mechanically)**\n\n- This Airworthiness Directive (AD) requires operators of certain Metro II/III family aircraft (SA226/SA227 variants listed in the Applicability section) that have pneumatic deicing boots to change the Limitations section of their Aircraft Flight Manual (AFM).\n- The new AFM text must require that the wing and tail leading edge pneumatic deicing boot system be switched on at the first sign of ice or when an ice detector alerts, and that the system be kept operating either in automatic cycling (if available) or manually cycled to minimise ice build-up.\n- The boots may only be turned off after the aircraft has left known or observed/detected icing and the airplane is “determined to be clear of ice.”\n- The AD also preserves any existing AFM prohibitions on boot use during specified phases (examples given: take‑off, final approach and landing). As an alternative to rewriting the AFM, the operator may insert a copy of the Directive into the AFM before the paragraph covering Operation in Icing Conditions.\n\n**Who this affects**\n\n- Aircraft owners/operators and flight crews of the listed SA226 and SA227 models equipped with pneumatic deicing boots (see the AD’s Applicability section for exact model list).\n- Aircraft maintenance and flight operations staff, because the AFM must be revised and crew procedures updated; training or briefings for crews will likely be required.\n- Regulatory/compliance personnel responsible for ensuring AFM contents meet CASA AD requirements.\n\n**Why it matters (stated purpose and practical effect)**\n\n- The AD’s stated purpose is to correct an unsafe condition related to ice accumulation on leading edges by forcing earlier and continued use of pneumatic boots when icing is detected or observed. Mechanically, it changes pilot behaviour: boots must be activated at first sign/detector warning and kept cycling until clear, except where the AFM already prohibits use.\n\n**Costs, incentives and trade-offs**\n\n- Direct compliance costs: revising the AFM (or inserting the AD text), distributing the change to crews, and training/briefing pilots on the new procedures.\n- Operational effects: crews are required to activate deicing boots sooner and to maintain boot operation until the airplane is clear, which may increase the number of boot cycles. That can increase wear on the boots and potentially increase maintenance or replacement costs over time.\n- Safety trade-off: earlier and continued boot operation reduces the risk of hazardous ice accumulation but may cause more frequent boot cycling triggered by spurious detector alerts or ambiguous visual observations.\n\n**Implementation and compliance considerations**\n\n- The AD is implemented by amending the AFM or inserting the AD text into the AFM. CASA enforces AD compliance; pilots make in‑flight decisions about activation based on the required rule (first sign of ice or ice detector). The phrases “first sign of ice” and “determined to be clear of ice” introduce some operational judgement for crews, which creates modest implementation risk (variation in how different crews interpret and apply the rule).\n\n**Market and organisational effects**\n\n- The directive imposes a narrowly targeted operational requirement on a limited set of aircraft models. It does not mandate hardware modification, new equipment, or impose requirements across different manufacturers, so effects on competition, ownership, or broader market structure are negligible.\n- Costs and benefits are concentrated: operators of the listed types bear the compliance and potential maintenance costs and receive the safety benefit; other operators are unaffected.\n\n**Where the directive says this (source sections)**\n\n- Applicability: lists the SA226/SA227 models affected.\n- Requirement: contains the exact AFM text to be incorporated (activation at first sign/detector, automatic or manual cycling, and conditions for deactivation).\n\n**Bottom line**\n\n- The AD requires a simple AFM change and a change in crew operating behaviour: switch on boots at first sign/detector and keep them cycling until the airplane is clear of icing (except where the AFM already bans boot use for certain flight phases). It is a targeted safety procedure change with modest compliance costs (AFM revision, training) and potential operational costs from increased boot cycling and maintenance."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — prescribing specific operational procedures for deicing boots on particular Metroliner aircraft models. There is no evidence of scope creep; it addresses exactly what the title suggests (operation of deicing boots) without expanding into unrelated maintenance, design, or operational areas."},"complexity_factors":["Single, clearly defined applicability section listing 11 specific aircraft models","One primary requirement with straightforward alternative compliance method","No nested definitions or extensive cross-referencing to other legislation","Simple conditional logic (when to activate, when to deactivate) presented in plain bullet points","Short document (approximately 300 words) with clear structure (Applicability, Requirement, Compliance implied)","Only one regulatory reference (subregulation 39.1(1) of CAR 1998) in preamble"],"plain_english_summary":"This AD requires operators of Fairchild Swearingen Metroliner SA226/SA227 aircraft with pneumatic deicing boots to revise flight manuals with stricter boot-use rules: activate boots at the first sign of ice or detector alert, keep them cycling (automatic or manual) until clear of icing, and only switch them off after confirmed ice-free and out of icing conditions, with takeoff/final/landing use restricted unless specifically allowed. It targets pilots, operators, and maintainers to reduce ice-related safety risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-swsa226-87-operation-of-deicing-boots","history":"/api/acts/ad-swsa226-87-operation-of-deicing-boots/history","analysis":"/api/acts/ad-swsa226-87-operation-of-deicing-boots/analysis","conflicts":"/api/acts/ad-swsa226-87-operation-of-deicing-boots/conflicts","importantCases":"/api/acts/ad-swsa226-87-operation-of-deicing-boots/important-cases","documents":"/api/acts/ad-swsa226-87-operation-of-deicing-boots/documents"}}