{"id":"F2006B05515","name":"AD/PA-23/88 Amdt 1 - Aircraft Flight Manual, Flight into Icing Conditions","slug":"ad-pa-23-88-amdt-1-aircraft-flight-manual-flight-into-icing-conditions","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46377,"registerId":"commonwealth-F2006B05515-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 revokes Airworthiness Directive (AD) AD/PA-23/88 and issues the following 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/PA-23/88","sectionType":"part","heading":"AD/PA-23/88","content":"# AD/PA-23/88\n\nAmdt 1\n\n  \n\nAircraft Flight Manual, Flight into Icing Conditions\n\n  \n7/2000","sortOrder":1},{"sectionNumber":"\"WARNING\"","sectionType":"part","heading":"\"WARNING\"","content":"# \"WARNING\"\n\nSevere icing may result from environmental conditions outside of those for which the aircraft is certificated.\n\nFlight in freezing rain, freezing drizzle, or mixed icing conditions (super cooled liquid water and ice crystals) may result in:\n\n    ice build-up on protected surfaces and exceed the capability of the ice protection system, or\n    ice forming aft of the protected surfaces.\n\nThis ice may not be shed using the ice protection systems, and may seriously degrade the performance and controllability of the aircraft.\n\nDuring flight, severe icing conditions that exceed those for which the aircraft is certificated shall be determined by the visual cues described below. If one or more of these visual cues exists, immediately request priority handling from Air Traffic Control to facilitate a route or an altitude change to exit the icing conditions. The cues are:\n\n    unusually extensive ice accumulation on the airframe and windscreen in areas not normally observed to collect ice, and/or\n    accumulation of ice on the upper surface of the wing aft of the protected area, and/or\n    accumulation of ice on the engine nacelles and propeller spinners farther aft than normally observed.","sortOrder":2},{"sectionNumber":"THE FOLLOWING WEATHER CONDITIONS MAY BE ","sectionType":"part","heading":"THE FOLLOWING WEATHER CONDITIONS MAY BE CONDUCIVE TO SEVERE IN-FLIGHT ICING:","content":"# THE FOLLOWING WEATHER CONDITIONS MAY BE CONDUCIVE TO SEVERE IN-FLIGHT ICING:\n\n    Visible rain at temperatures below 0 degrees Celsius ambient air temperature;\n    Droplets that splash or splatter on impact at temperatures below 0 degrees Celsius ambient air temperature.","sortOrder":3},{"sectionNumber":"PROCEDURES FOR EXITING A SEVERE ICING","sectionType":"part","heading":"PROCEDURES FOR EXITING A SEVERE ICING","content":"# PROCEDURES FOR EXITING A SEVERE ICING\n\nENVIRONMENT: (These procedures are applicable to all flight phases from take-off to landing.)\n\nMonitor the ambient air temperature.\n\nWhile severe icing may form at temperatures as cold as -18 degrees Celsius, increased vigilance is warranted at temperatures around freezing when visible moisture is present.","sortOrder":4}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment primarily clarifies and formalises AFM content and crew procedures about severe icing; it revokes the prior AD and replaces it with updated warning text and exit procedures. It does not materially broaden the regulatory reach (no new equipment mandates, inspections, or expanded applicability are introduced in the text provided) and therefore does not appear to change the AD’s core safety purpose or significantly expand scope beyond the original intent."},"complexity_factors":["Short single‑topic AD (primarily AFM text and crew procedures)","Limited legal cross‑references (refers to CAR 1998 subreg 39.1(1) and revokes AD/PA‑23/88)","Few conditional provisions — mainly visual cues acting as subjective triggers","Technical aviation terminology (freezing rain, freezing drizzle, supercooled liquid water, protected areas) requiring domain knowledge","No nested exceptions or detailed compliance schedule included in the excerpt"],"plain_english_summary":"**What this instrument does (mechanics first)**\n\n- The Civil Aviation Safety Authority (CASA) delegate has revoked an earlier airworthiness directive (AD) and issued AD/PA-23/88 Amendment 1 under subregulation 39.1(1) of the CAR 1998. The AD requires operators to take the corrective action set out in the AD for the aircraft named in the applicability section (i.e. update or amend the Aircraft Flight Manual and crew procedures as required by the AD).\n\n- The text the AD requires to be in the Aircraft Flight Manual (AFM) and crew guidance is: a prominent WARNING about the possibility of severe icing outside certificated conditions, a short list of the atmospheric situations that may cause severe icing, visual cues pilots should use in flight to recognise severe icing, and basic procedures for exiting severe icing conditions (including monitoring ambient air temperature and seeking priority handling from Air Traffic Control to change route/altitude).\n\n**Who this affects**\n\n- Aircraft operators and owners of the aircraft type listed in the AD’s applicability (the AD title indicates it applies to PA‑23 series aircraft or the aircraft identified in the AD).\n- Pilots and flight crew of those aircraft, because the AD changes what must be in the AFM and instructs in‑flight conduct (monitor temperatures, recognise visual cues, request ATC priority to exit icing).\n- Maintenance/administrative staff who must amend the AFM and record compliance with the AD.\n\n**Why it matters (stated purpose and practical implications)**\n\n- The AD’s stated purpose is to correct an unsafe condition related to in‑flight icing: it warns that freezing rain, freezing drizzle or mixed icing (supercooled liquid water plus ice crystals) can produce ice build‑up beyond the capability of the aircraft’s ice protection system or produce ice aft of protected areas that cannot be shed by the anti‑ice/de‑ice systems (see the AD’s WARNING section).\n\n- Practically, the AD changes behaviour by: (a) requiring flight crews to monitor ambient air temperature and be especially vigilant near 0°C when visible moisture is present; (b) requiring crews to look for certain visual cues of severe icing (extensive ice in unusual places, ice on the upper wing surface aft of protected areas, ice on nacelles/spinners farther aft than normal); and (c) requiring immediate action if those cues are seen — specifically, requesting priority handling from ATC to enable route or altitude changes to exit the conditions.\n\n**Who pays, who decides, and what changes**\n\n- Who pays: operators bear the direct costs — updating the AFM, issuing the revised documentation to crews, and any associated training or briefing time. Indirect costs may flow from more frequent diversions, altitude/route changes, or cancelled sectors if crews avoid or exit icing conditions.\n- Who decides: CASA (through its delegate) sets the required AFM content and compliance timing; pilots make in‑flight decisions (using the visual cues) and request ATC assistance; ATC decides whether and how to provide priority handling subject to traffic and control constraints.\n- Behaviour changes required: AFM must be amended; pilots must monitor ambient temperature and visual cues, and act (request priority handling/exit route or altitude) when severe icing is recognised.\n\n**Trade‑offs, costs and implementation risks to note**\n\n- Compliance burden is mainly administrative (AFM revision and training) and operational (possible diversions or altitude/route changes). The AD does not mandate equipment changes or inspections.\n- The AD relies on visual cues and pilot judgement to declare a condition as “severe icing.” That introduces some subjectivity and potential implementation risk (different pilots may judge cues differently). The AD mitigates this by listing specific visual cues and linking them to an immediate action (request priority handling).\n- The measure directs private actors (operators and pilots) to adopt safer conduct at the cost of operational disruption; it does not itself create a maintenance or equipment retrofit requirement.\n\n**Source‑stated rationale (as claimed) and brief testing against costs/incentives**\n\n- Source claim: the AD is necessary because severe icing conditions can exceed the aircraft’s certification and the ice‑protection system’s capability (see WARNING). The AD formalises warnings and procedures in the AFM to reduce the safety risk.\n- Testing that claim against costs/incentives: the principal cost is modest (manual changes, training, occasional operational disruption). The incentive for operators and pilots is aligned with safety — to avoid loss of control — so behaviour change (requesting priority handling and exiting icing) is straightforward to monitor and enforce administratively (AFM compliance records) though in‑flight compliance depends on crew recognition and ATC availability.\n\n"},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the 1988 directive. It updates the flight manual requirements for the same aircraft type (PA-23) regarding the same safety issue (icing conditions). The amendment appears to refine and clarify the warning language and procedures rather than expand the directive's reach to new aircraft types or operational contexts."},"complexity_factors":["Single, specific aircraft type (Piper PA-23) with narrow applicability","No defined terms section or complex legislative definitions","No cross-references to other legislation beyond the basic enabling power (CAR 1998 subregulation 39.1(1))","Straightforward operational instructions written in plain language","Simple structure: warning signs, weather conditions, exit procedures","No conditional logic or nested exceptions — just 'if you see this, do that' instructions","Short document (approximately 400 words) with clear visual formatting"],"plain_english_summary":"This AD replaces the prior PA-23 directive and requires updates to the Piper PA-23 Aircraft Flight Manual to add critical guidance on recognizing and escaping severe icing—especially in freezing rain, freezing drizzle, or mixed supercooled conditions that can overwhelm de‑icing systems.  \n\nIt affects PA-23 owners, operators, and pilots: watch for atypical ice buildup, monitor outside air temperature, and seek immediate ATC assistance to change altitude or route if severe icing is encountered to prevent loss of control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-23-88-amdt-1-aircraft-flight-manual-flight-into-icing-conditions","history":"/api/acts/ad-pa-23-88-amdt-1-aircraft-flight-manual-flight-into-icing-conditions/history","analysis":"/api/acts/ad-pa-23-88-amdt-1-aircraft-flight-manual-flight-into-icing-conditions/analysis","conflicts":"/api/acts/ad-pa-23-88-amdt-1-aircraft-flight-manual-flight-into-icing-conditions/conflicts","importantCases":"/api/acts/ad-pa-23-88-amdt-1-aircraft-flight-manual-flight-into-icing-conditions/important-cases","documents":"/api/acts/ad-pa-23-88-amdt-1-aircraft-flight-manual-flight-into-icing-conditions/documents"}}