{"id":"F2006B10806","name":"AD/IAI-W/6 - Audio Intercom System - Warning Placard and Modification","slug":"ad-iai-w-6-audio-intercom-system-warning-placard-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56284,"registerId":"commonwealth-F2006B10806-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/IAI-W/6 - Audio Intercom System - Warning Placard and Modification","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nIsrael Aircraft Industries 1123 and 1124 (Westwind) Series Aeroplanes\n\nAD/IAI-W/6 Audio Intercom System \\- Warning Placard and Modification\n\n  \n5/81\n\nApplicability: All models 1123, 1124 and 1124A with S/Nos. 151 to 315 except 294, 296, 297, 309,\n\n310 and 314.\n\nDocument: IAI Service Bulletin WW-25 for Model 1123 aeroplanes. IAI Service Bulletin WW- 24-23 for Model 1124 and 1124A aeroplanes.\n\nNote: FAA Emergency Airworthiness Directive 81-07-07 dated 20 March 1981 refers.\n\nCompliance: Within 100 hours time in service after 31 May 1981.\n\nBackground: In an incident overseas a resistor in the intercom system overheated and initiated a fire on the ground. A check of Australian aircraft of this type revealed that overheating of the same resistor has occurred but not to the degree necessary to initiate a fire.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD's scope is aligned with its stated safety purpose: it targets the subset of IAI Westwind aeroplanes where the intercom resistor overheating was observed (Models 1123, 1124 and 1124A with S/Ns 151–315, excluding listed S/Ns). The directive requires actions set out in the manufacturer service bulletins to address that specific hazard and does not broaden mandated measures beyond those aircraft or the intercom issue. (Applicability, Document, Background)"},"complexity_factors":["Narrow technical scope limited to specific aircraft models and serial-number range (Applicability)","Requires action per external manufacturer service bulletins rather than full technical detail in the AD itself (Document)","Fixed, short compliance window tied to flight hours (100 hours after 31 May 1981) creating scheduling pressure (Compliance)","Some serial-number exceptions increase administrative checking to determine applicability (Applicability)"],"plain_english_summary":"### What this directive does\n\nThis Airworthiness Directive (AD) orders owners/operators of certain Israel Aircraft Industries (IAI) Westwind aeroplanes to follow a specified warning-placard fitment and modification procedure for the audio intercom system. The AD points operators to IAI Service Bulletin WW-25 (Model 1123) and WW-24-23 (Models 1124 and 1124A) as the documents describing the required work. (Document)\n\nMechanically, the AD:\n- Identifies which aeroplanes are affected by serial number range and exceptions. Operators must check their aeroplane's serial number against the list. (Applicability)\n- Requires compliance within a fixed window: the work must be completed within 100 hours time-in-service after 31 May 1981. (Compliance)\n\n### Who this affects\n- Owners and operators of IAI Model 1123, 1124 and 1124A aeroplanes with serial numbers 151 to 315, except for serial numbers 294, 296, 297, 309, 310 and 314. (Applicability)\n\n### Why it matters (official rationale and practical implications)\n- Official rationale: The AD follows an incident in which a resistor in the intercom system overheated and started a fire on the ground; inspections showed the same resistor has overheated on other Australian aircraft of these types, though not to the point of ignition in those cases. The AD is directed at preventing recurrence of that hazard. (Background)\n\n- Who pays: The cost of performing the placard installation and the modification described in the referenced service bulletins falls to the aircraft owner/operator because they must have the work performed to comply with the AD. (Document, Compliance)\n\n- Who decides: The Civil Aviation Safety Authority (via the AD) prescribes what must be done; the specific technical steps are set out in the referenced IAI service bulletins which the operator or their maintenance organisation must follow. (Document)\n\n- Compliance burden and practical trade-offs: Operators must identify affected serial numbers, obtain and follow the service bulletin instructions, schedule maintenance within the 100 hours time-in-service window, and bear the labour, parts and aircraft downtime costs. That creates concentrated direct costs for owners of affected aeroplanes and a diffuse safety benefit for operators and others using the aircraft. (Applicability, Document, Compliance)\n\n- Implementation risk and discretion: The AD prescribes compliance and points to manufacturer service bulletins for the technical method; the AD itself does not specify alternative methods or discretionary exemptions. Any variation from the service bulletin would typically need regulatory approval. (Document)\n\n- Effects on private choice and markets: The AD constrains operators of specified aircraft to undertake a mandated modification and fit a warning placard, reducing their choice about whether to defer the change. This may temporarily affect aircraft availability and maintenance workloads for providers who service these models. (Applicability, Document, Compliance)\n\n### Concrete mechanism of benefit and cost\n- Benefit mechanism: the modification and placard reduce the risk that the particular intercom resistor will overheat unnoticed and lead to fire, as identified in the incident that prompted the AD. (Background)\n- Cost mechanism: owners/operators pay for the parts, labour and downtime required to carry out the service-bulletin work within the specified compliance window. (Document, Compliance)\n\n### Source citations (where the AD states these points)\n- Affected aeroplanes and serial-number exceptions: (Applicability)\n- Required technical documents: IAI Service Bulletin WW-25 and WW-24-23 (Document)\n- Compliance deadline: within 100 hours time in service after 31 May 1981 (Compliance)\n- Reason for the AD: overheating resistor incident and subsequent findings (Background)\n"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive addressing a specific identified hazard in a specific aircraft type. It has not expanded beyond its original purpose of mandating an intercom system fix."},"complexity_factors":["Very short document (approximately 150 words)","Only 3 defined applicability criteria (aircraft model, serial number range, specific exclusions)","Single compliance requirement with clear deadline","No cross-references to other legislation beyond noting related FAA directive","No conditional logic or nested exceptions — straightforward 'do this by this date' structure","Background explanation is plain narrative, not technical procedural language"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it like a compulsory recall notice for aircraft, but with legal force.\n\n**What it does:** It requires owners and operators of specific Israel Aircraft Industries (IAI) Westwind business jets to install a **warning placard** and make **modifications** to the audio intercom system.\n\n**Why it matters:** A resistor in the intercom system has been overheating. Overseas, this caused an actual fire on the ground. Australian checks found the same overheating problem here — just not severe enough to start a fire yet. This AD prevents potential in-flight or ground fires by fixing the problem before it becomes catastrophic.\n\n**Who must comply:**\n- **Aircraft affected:** IAI Westwind models 1123, 1124, and 1124A\n- **Serial numbers:** 151 to 315, **except** 294, 296, 297, 309, 310, and 314\n- **Deadline:** Within 100 hours of flying time after 31 May 1981\n\n**What must be done:**\n- Follow the manufacturer's service bulletins (WW-25 for model 1123, WW-24-23 for models 1124/1124A)\n- Install warning placards and modify the intercom system as specified\n\n**The bottom line:** If you own or operate one of these specific Westwind jets in Australia, you legally cannot keep flying it beyond 100 hours after May 1981 without completing this safety fix."}},"importantCases":[],"_links":{"self":"/api/acts/ad-iai-w-6-audio-intercom-system-warning-placard-and-modification","history":"/api/acts/ad-iai-w-6-audio-intercom-system-warning-placard-and-modification/history","analysis":"/api/acts/ad-iai-w-6-audio-intercom-system-warning-placard-and-modification/analysis","conflicts":"/api/acts/ad-iai-w-6-audio-intercom-system-warning-placard-and-modification/conflicts","importantCases":"/api/acts/ad-iai-w-6-audio-intercom-system-warning-placard-and-modification/important-cases","documents":"/api/acts/ad-iai-w-6-audio-intercom-system-warning-placard-and-modification/documents"}}