{"id":"F2006B10135","name":"AD/G73/23 - Operation of Deicing Boots","slug":"ad-g73-23-operation-of-deicing-boots","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55706,"registerId":"commonwealth-F2006B10135-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/G73/23 Operation of Deicing Boots 7/2","sectionType":"part","heading":"AD/G73/23 Operation of Deicing Boots 7/2000","content":"# AD/G73/23 Operation of Deicing Boots 7/2000\n\nApplicability: Model G-73 and G-73T series aircraft fitted with pneumatic deicing boots.\n\nRequirement: Revise the Limitations Section of the Aircraft Flight Manual (AFM) by incorporating the following:\n\n\" Except if the AFM otherwise specifies that deicing boots should not be used for certain phases of flight (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 completion of an entire deicing cycle after leaving icing conditions.\"\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 99-19-07 Amendment 39-11296 refers.","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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD remains tightly focused on its original purpose: correcting unsafe deicing boot operation procedures for a specific aircraft type. The scope has not expanded beyond the G-73 series and the specific unsafe condition related to ice accumulation management."},"complexity_factors":["Single, specific aircraft model family (G-73 series)","One clear action required (AFM amendment)","Only 2 defined operational conditions (activation trigger and deactivation rule)","No cross-references to other legislation beyond a single FAA AD citation in a note","Alternative compliance method provided (inserting the directive itself into the AFM)","Plain language operative words ('at the first sign', 'whichever occurs first')","No nested exceptions or conditional logic chains"],"plain_english_summary":"This CASA Airworthiness Directive affects owners/operators of Grumman G‑73/G‑73T “Mallard” aircraft fitted with pneumatic de‑icing boots. It requires updating the Aircraft Flight Manual with new procedures: activate boots at the first sign of icing or on ice‑detector alert, use automatic cycling if available or manually cycle as needed, and keep them on until a full de‑ice cycle is completed after leaving icing conditions. The Certificate of Registration holder may log and sign the AFM amendment. The rule closes a safety gap by preventing dangerous ice buildup."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This directive does not expand the legislation's scope beyond addressing the specific unsafe condition for the listed aircraft models. It prescribes an operational requirement (AFM amendment) for deicing-boot use consistent with the referenced FAA AD. Mechanically it standardises pilot action and AFM text for the specified models but does not add maintenance mandates, additional affected models, or broader regulatory powers. Therefore it remains within the original, model-specific safety-remedy purpose."},"complexity_factors":["Single, narrow applicability: only G-73 and G-73T models with pneumatic deicing boots","One primary operative requirement (revise AFM Limitations) with a short prescribed text","Two small conditional qualifications (\"except if the AFM otherwise specifies\" and an alternative insertion option)","No defined-terms section, few cross-references (only FAA AD 99-19-07 and subregulation 39.1(1) authority reference)","Limited implementation mechanics (CoR holder may amend AFM and sign logbook)","Two non‑mandatory notes (optional chemical treatment and reference to FAA AD)"],"plain_english_summary":"**What this directive does (mechanically)\n\n- Who it applies to: Owners/operators of Grumman (G-73 and G-73T) series aircraft that have pneumatic deicing boots installed.  (Deicing boots are inflatable rubber surfaces on wing and tail leading edges that break off accumulated ice.)\n\n- What it requires (Requirement section): Update the Aircraft Flight Manual (AFM) Limitations section to include the following operating rules for wing and tail leading-edge pneumatic deicing boots:  \n  - Activate the deicing boots at the first sign of ice anywhere on the aircraft, or when an onboard ice detector warns, whichever happens first.  \n  - Once activated, either leave the system in automatic cycling mode (if the system has it) or manually cycle the boots as needed to minimise ice buildup.  \n  - Do not switch the boots off until after completing an entire deicing cycle once the aircraft has left icing conditions.  \n  - The AD allows an alternative: inserting a copy of the directive text into the AFM in front of the existing \"Operation in Icing Conditions\" paragraph.\n\n- Who can make the AFM change: The certificate of registration (CoR) holder for the aircraft may make the AFM amendment and sign the aircraft logbook to record compliance.\n\n- Additional notes included by the directive: Periodic treatment of boots with an ice-phobic compound (example given: \"ICEX™\") can reduce ice adhesion. The directive also cites a related FAA airworthiness directive (FAA AD 99-19-07).\n\nWhy it matters (purpose claims and practical effects)\n\n- The directive is issued by CASA under the airworthiness rules to correct an unsafe condition related to in-flight ice accumulation on these models. It imposes a specific operational requirement on pilots/operators to ensure deicing boots are used promptly and cycled until clear of icing conditions. (Requirement section; Compliance mechanism: AFM amendment and logbook entry.)\n\n- Who pays / who acts: Aircraft operators (CoR holders) bear the administrative cost of amending the AFM and recording compliance. Pilots and flight crews must follow the new AFM limitation in every flight where icing is encountered. There may be modest recurring costs if operators choose to use ice-phobic treatments for the boots.\n\n- Behaviour change and trade-offs: Pilots are directed to activate boots at the first sign of icing or on ice-detector annunciation and to continue cycling until clear of icing. This reduces discretionary delay in using boots (the rule preserves any AFM-specific prohibitions for certain phases such as take-off or landing). The change primarily shifts behaviour toward earlier and sustained use of boots, which trades off minimal operational actions (switching/cycling boots) against reduced ice accretion risk.\n\n- Compliance burden and implementation risk: The directive is narrowly targeted and mechanically simple to implement—an AFM insertion/amendment and a logbook entry. Operational compliance depends on pilot adherence; there are no complex inspections or parts changes mandated. The directive references an FAA AD but does not itself mandate additional maintenance other than optional chemical treatment.\n\nConcrete sources in the text\n\n- Applicability: \"Model G-73 and G-73T series aircraft fitted with pneumatic deicing boots.\" (Applicability section.)\n- Required AFM text and cycling/deactivation rules: set out in the Requirement section inserted into the AFM Limitations.\n- Implementation authority: \"This AFM amendment may be accomplished by the aircraft CoR holder, who can sign the aircraft logbook for completion of this Directive.\" (Requirement section.)\n- Optional treatment and cross-reference: Note 1 (ICEX™) and Note 2 (FAA AD 99-19-07).\n\nNet operational effect in one sentence: Operators of affected G-73/G-73T aircraft must amend their AFM to require prompt activation and continued cycling of pneumatic deicing boots when icing is detected, and keep the system operating until a full deicing cycle is complete after leaving icing conditions—recorded by the CoR holder in the logbook."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g73-23-operation-of-deicing-boots","history":"/api/acts/ad-g73-23-operation-of-deicing-boots/history","analysis":"/api/acts/ad-g73-23-operation-of-deicing-boots/analysis","conflicts":"/api/acts/ad-g73-23-operation-of-deicing-boots/conflicts","importantCases":"/api/acts/ad-g73-23-operation-of-deicing-boots/important-cases","documents":"/api/acts/ad-g73-23-operation-of-deicing-boots/documents"}}