{"id":"F2006B06505","name":"AD/RAD/48 - Collins TCAS II and TCAS 94 Systems","slug":"ad-rad-48-collins-tcas-ii-and-tcas-94-systems","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48076,"registerId":"commonwealth-F2006B06505-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RAD/48 - Collins TCAS II and TCAS 94 Systems","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nRadio Communication and Navigation Equipment\n\nAD/RAD/48 Collins TCAS II and TCAS 94 Systems 8/92 Applicability: All Collins Traffic Alert and Collision Avoidance TCAS II and TCAS 94 systems. Requirement: 1. Deactivate and placard the TCAS equipment as follows:\n\n    Pull and band the circuit breaker that applies electrical power to the TCAS system,\n\n    b. Fabricate a placard with the following words in 4mm high letters \\`TCAS II Inoperative’ or ‘TCAS 94 Inoperative’ as appropriate, and\n\n    c. Install this placard adjacent to the TCAS control unit within the pilot’s clear view.\n\n    2. Modify the TCAS equipment in accordance with either of the following Collins Service Bulletins:\n\n    SB TTR-920-34-C Revision 1 dated 20 May 1991, or\n\n    b. SB TTR-920-34-07 Revision 1 dated 20 May 1991.\n\nNote: FAA AD 91-10-01 Amendment 39-8002 refers.\n\nCompliance: 1. Prior to further flight after 23 August 1992 or prior to flight in United States airspace for Requirement 1.\n\n2. Prior to reactivating the TCAS equipment.\n\nNote: Compliance with Requirement 2 is considered terminating action for this Directive.\n\nBackground: The FAA has received several reports of problems on aircraft equipped with Collins TCAS II or TCAS 94 systems. The crew members of the involved aircraft report that targets suddenly appear or are moving at a very high rate of speed toward their aircraft, which causes a ‘Traffic Advisory (TA)’ or ‘Resolution Advisory (RA)’. The sudden display of these advisories often causes the crew to rapidly change altitude, which could result in an undesirable disruption of the Air Traffic Control System.\n\nCompliance with this Directive, prevents the sudden appearance of spurious TCAS advisories.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive does not broaden applicability beyond Collins TCAS II and TCAS 94 units; it imposes temporary deactivation and mandates a specified manufacturer modification as the corrective action. This is consistent with the Directive’s stated safety objective and mirrors the referenced FAA action (Applicability; Requirements; Note)."},"complexity_factors":["Clear, prescriptive corrective actions (deactivate, placard, modify) reduce legal ambiguity (Requirements 1–2).","Mandatory use of specific Collins Service Bulletins creates a single technical remedy but requires access to and performance of manufacturer procedures (Requirement 2).","Time-based compliance constraint: immediate grounding for affected TCAS until placarded or modified imposes operational disruption (Compliance: prior to further flight after 23 Aug 1992 or prior to flight in US airspace).","Terminating-action mechanic: modification relieves operational restriction, concentrating compliance into a single retrofit (Note: terminating action).","Scope limited to named Collins TCAS models reduces applicability complexity but requires accurate fleet identification (Applicability).","Safety-critical context increases stakes for correct maintenance and verification despite straightforward textual obligations (Background)."],"plain_english_summary":"This Directive requires aircraft with Collins TCAS II or TCAS 94 units to be deactivated immediately (pull and band the circuit breaker), fitted with a 4 mm‑letter placard stating the unit is inoperative, and then modified using one of two specified Collins Service Bulletins before the TCAS may be reactivated (Requirements 1–2; Compliance). Operators and maintenance organisations must carry out and pay for the deactivation, placarding and modification; the stated aim is to prevent spurious traffic or resolution advisories that can prompt abrupt altitude changes (Background)."},"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 is a discrete, targeted safety directive addressing a specific technical fault in specific avionics equipment. It has not expanded beyond its original purpose of grounding/modifying faulty collision avoidance systems."},"complexity_factors":["Single, specific technical subject matter (one manufacturer's equipment)","Only 2 compliance requirements with clear deadlines","Minimal defined terms (only equipment model names)","No cross-references to other legislation beyond a single FAA reference note","Straightforward conditional logic (do X before date Y, or do Z before reactivation)","Short document (approximately 250 words)"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority. It applies to **all aircraft fitted with specific Collins brand collision avoidance systems** (TCAS II and TCAS 94).\n\n**What it requires:**\n- **Immediate action:** Airlines must disable these systems by pulling the circuit breaker and putting up a warning sign saying the equipment is broken, before flying after 23 August 1992 or before entering US airspace.\n- **Permanent fix:** The equipment must be modified according to specific manufacturer service bulletins before it can be turned back on.\n\n**Why it matters:**\nThese systems were giving **false alarms** — suddenly showing imaginary aircraft speeding toward the plane. This caused pilots to panic and change altitude suddenly, which could cause chaos in air traffic control and potentially create real collision risks. The directive forces operators to either shut the faulty systems down or fix them properly."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rad-48-collins-tcas-ii-and-tcas-94-systems","history":"/api/acts/ad-rad-48-collins-tcas-ii-and-tcas-94-systems/history","analysis":"/api/acts/ad-rad-48-collins-tcas-ii-and-tcas-94-systems/analysis","conflicts":"/api/acts/ad-rad-48-collins-tcas-ii-and-tcas-94-systems/conflicts","importantCases":"/api/acts/ad-rad-48-collins-tcas-ii-and-tcas-94-systems/important-cases","documents":"/api/acts/ad-rad-48-collins-tcas-ii-and-tcas-94-systems/documents"}}