{"id":"F2006B02159","name":"AD/AC/98 - Operation of Deicing Boots","slug":"ad-ac-98-operation-of-deicing-boots","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41389,"registerId":"commonwealth-F2006B02159-current","compilationNumber":null,"startDate":"2026-04-01","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/AC/98 Operation of Deicing Boots 7/20","sectionType":"part","heading":"AD/AC/98 Operation of Deicing Boots 7/2000","content":"# AD/AC/98 Operation of Deicing Boots 7/2000\n\nApplicability: All models 680, 680E, 680F, 680FL, 680FL(P), 680T, 680V, 680W, 681, 685, 690,\n\n690A, 690B, 690C, 690D, 695, 695A and 695B aircraft fitted 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 leaving icing conditions and 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.\n\nThis AFM amendment may be accomplished by the aircraft CoR holder, who can sign the aircraft logbook for completion of this Directive.\n\nNote 1: Ice adhesion can be reduced by periodic treatment of deicing boots with a deicing compound such as “ICEX”, an ice-phobic chemical spray.\n\nNote 2: FAA AD 2000-02-30 Amendment 39-11548 refers.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a straightforward safety directive focused specifically on deicing boot operation procedures. It has not expanded beyond its original purpose of addressing ice accumulation risks on specific aircraft models."},"complexity_factors":["Very short document (approximately 300 words)","Only 1 defined term implicitly referenced (AFM — Aircraft Flight Manual)","No cross-references to other legislation beyond a single note referencing related FAA directive","Simple conditional structure: single requirement with straightforward exceptions (take-off, landing phases)","Clear, prescriptive language with minimal legal drafting complexity","Single compliance pathway with one alternative method (inserting the directive itself into the manual)"],"plain_english_summary":"This AD applies to certain Aero Commander twin‑engine aircraft with pneumatic deicing boots and requires a mandatory Aircraft Flight Manual revision. It tells pilots to activate and keep deicing boots operating at the first sign of ice (or an ice‑detector alarm), and only turn them off after exiting icing conditions and confirming all ice is gone. The registered owner/operator may record the AFM change in the aircraft logbook. The measure reduces the risk of aerodynamic stall and loss of control from ice accumulation."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD stays narrowly focused on the operation of pneumatic deicing boots and the AFM amendment required to enforce that operating practice. It does not expand the regulatory domain beyond the original safety objective (prompt and sustained use of deicing boots in icing conditions), nor does it add unrelated obligations, economic regulation, or new certification requirements. The inclusion of a note suggesting ice-phobic treatment and a reference to a related FAA AD align the instrument with practical measures and international practice but do not broaden its substantive scope."},"complexity_factors":["Short, single-topic instrument (one main mandatory action)","Applicability limited to a finite list of aircraft models (about 20 models listed)","One principal operational requirement with straightforward conditional logic (activate on first sign or detector; continue until clear)","Two informational notes (ice-phobic treatment and FAA cross-reference)","No defined-term section, no nested exceptions beyond normal AFM exclusions for phases of flight","Minor cross-reference to FAA AD 2000-02-30 but no complex cross-legislation dependencies"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Requires operators of specific aircraft models fitted with pneumatic deicing boots to update the Aircraft Flight Manual (AFM) Limitations section to include a mandatory operating procedure for those boots.  (See \"Applicability\" and \"Requirement\".)\n\n- The required AFM text says, in essence:\n  - Activate wing and tail leading-edge pneumatic deicing boots at the first sign of ice or on an ice-detector annunciation, whichever happens first.\n  - Once started, either leave the system in its automatic cycling mode (if the system has one), or manually cycle it as needed to minimise ice accretion.\n  - Do not switch the boots off until after leaving icing conditions and confirming the aircraft is clear of ice.\n  - Usual AFM exclusions remain in place for certain phases of flight where boots are not to be used (for example take-off, final approach and landing).\n\n- The AD allows the exact text to be placed in the AFM or for a copy of the Directive to be inserted into the AFM before the existing icing-operations paragraph.\n\n- The aircraft Certificate of Registration (CoR) holder may make the AFM amendment and sign the aircraft logbook to record compliance.\n\n- Two notes accompany the directive: one advising periodic application of an ice-phobic treatment (e.g. “ICEX™”) can reduce ice adhesion to boots, and another referring to a related FAA directive.\n\nWhy the directive is issued (claimed purpose) and how that maps to costs and trade-offs\n\n- The directive is presented as a safety measure to correct an unsafe condition (ice accretion) by ensuring deicing boots are used promptly and continuously while in icing conditions.\n\n- Who pays: aircraft owners/operators and their crews pay the costs. Those costs are mainly:\n  - Administrative: amending AFMs and signing logbooks.\n  - Operational: pilots alter standard operating behaviour to activate/operate boots earlier and potentially more often.\n  - Maintenance: increased cycling may increase wear on boots and associated pneumatic systems, leading to earlier repair or replacement cycles; if operators adopt periodic ice-phobic treatments there is a small recurring materials and labour cost.\n\n- Who decides and who must act: CASA (via the delegate) issues the AD; Certificate of Registration holders implement the AFM change and record compliance; pilots are obliged to follow the AFM when operating in icing conditions.\n\n- Incentives and behaviour changes: the AD creates a clear, low-discretion rule about when boots must be used (first sign of icing or detector annunciation). That tends to shift pilot behaviour toward earlier activation and continuing protection rather than delaying activation until ice is visibly problematic. The option to use automatic cycling (if available) or manual cycling provides some flexibility to crews.\n\n- Trade-offs and implementation risk:\n  - Safety benefit: earlier and consistent boot use reduces the chance of hazardous ice buildup on leading edges.\n  - Operational cost: more frequent cycling may shorten boot service life and increase maintenance events and costs.\n  - Human factors: effective compliance depends on crews recognising the first sign of ice or responding to ice detectors as required; training and checklists must be updated.\n  - Equipment reliance: if ice detectors give false positives, crews may operate boots more frequently than needed; if detectors miss icing, the requirement still captures the ‘‘first sign of ice’’ clause, which is crew-dependent.\n\n- Market and competition effects: the AD imposes a uniform operational requirement across affected models and does not create a licensing barrier or restrict which firms can operate those aircraft. Smaller operators may feel the relative cost burden more due to maintenance/service cost increases, but there is no discrimination among providers.\n\n- Bureaucratic discretion and compliance burden: the directive is prescriptive but limited in scope. CASA has exercised standard AD authority to mandate an AFM change. The compliance action is simple (AFM amendment and logbook entry), so administrative discretion after issuance is low. Most of the ongoing compliance burden falls on pilots and MROs (maintenance organisations).\n\n- Substitution and unintended consequences:\n  - Operators might adopt ice-phobic treatments to reduce adhesion, adding another recurring cost; that treatment could reduce maintenance needs if effective.\n  - Increased boot cycling might uncover other system reliability issues (compressor wear, valve wear), shifting maintenance focus.\n\nWhere the directive sits relative to other rules\n\n- The AD expressly references FAA AD 2000-02-30, indicating regulatory alignment with a previously issued FAA requirement; it does not broaden obligations beyond the operational requirement stated.\n\nKey practical points for operators\n\n- Update AFMs (or insert the AD text) and record the change in the aircraft logbook; the CoR holder may perform this.\n- Train flight crews to activate and operate boots at first sign of ice or on ice-detector annunciation and to leave them operating until clear of ice.\n- Expect potential increases in maintenance workload and costs tied to deicing boot use and consider whether periodic application of an ice-phobic treatment is operationally or economically sensible.\n\n(References: Applicability, Requirement, Note 1, Note 2.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-98-operation-of-deicing-boots","history":"/api/acts/ad-ac-98-operation-of-deicing-boots/history","analysis":"/api/acts/ad-ac-98-operation-of-deicing-boots/analysis","conflicts":"/api/acts/ad-ac-98-operation-of-deicing-boots/conflicts","importantCases":"/api/acts/ad-ac-98-operation-of-deicing-boots/important-cases","documents":"/api/acts/ad-ac-98-operation-of-deicing-boots/documents"}}