{"id":"F2006B06517","name":"AD/RAD/63 - KT 76A ATC Transponder","slug":"ad-rad-63-kt-76a-atc-transponder","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48120,"registerId":"commonwealth-F2006B06517-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RAD/63 - KT 76A ATC Transponder","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/63 KT 76A ATC Transponder 10/98\n\nApplicability: AlliedSignal KT 76A Air Traffic Control (ATC) Transponders, part numbers 066- 1062-00, -10 and -02 with serial numbers 93,000 through 109,999 inclusive.\n\nNote: These transponders are known to be installed on, but not limited to, the following series of aircraft:\n\nManufacturer Aircraft Series\n\nCessna Aircraft Company 172, 182, T182, R182, 206, P206, U206, TP206, 210, T210, P210, 310, E310,\n\nT310 and 421\n\nTwin Commander Aircraft Company 500, 520, 560, 680, 681, 685, 690, 695\n\nand 720\n\nThe New Piper Aircraft Corporation (formerly known as Piper Aircraft Corporation)\n\nRaytheon Aircraft Corporation (formerly known as Beech Aircraft Corporation)\n\n  \nPA-31, PA-32 and PA-34\n\nE33, F33, G33, 35, J35, K35, L35, M35, P35, S35, V35, 36, A26, B36, D55, E55, 56, A56, 58, 58A, 95, B95, D95 and E95\n\nMooney Aircraft Corporation M20 McDonnell Douglas Helicopter Company 500N\n\nRequirement: Replace the two resistor network modules, RM401 and RM402, with new glass- coated parts in accordance with the ‘Modification Procedure’ section of AlliedSignal Service Bulletin SB KT 76A-7 dated July 1996. (When accomplished, this replacement is referred to as Mod 7.)\n\nNote: FAA AD 98-14-03 Amdt 39-10637 refers.\n\nCompliance: Prior to installation in an aircraft, but no later than 10 September 1999. This Airworthiness Directive becomes effective on 10 September 1998.\n\nBackground: The FAA has advised that KT 76A ATC transponders have been identified as transmitting misleading encoding altimeter information to ground-based ATC radar sites and proximate Traffic Alert and Collision Avoidance System (TCAS) equipped aircraft. The actions specified by this directive are intended to prevent the transmission of misleading encoding altimeter information from affected aircraft.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument enforces a targeted retrofit (Mod 7) to specified KT 76A transponders to prevent misleading encoded altimeter information. It does not broaden the range of affected equipment beyond the listed part and serial numbers, nor alter the nature of the corrective measure set out by the manufacturer and referenced FAA advisory."},"complexity_factors":["Narrow technical scope: single corrective action — replace RM401 and RM402 with specified glass‑coated parts.","Limited applicability: applies only to KT 76A units with listed part numbers and serial numbers 93,000–109,999.","Prescriptive compliance method: requires following AlliedSignal Service Bulletin SB KT 76A‑7 (Mod 7).","Fixed compliance timing: effective 10 Sep 1998 and must be done prior to installation or by 10 Sep 1999.","Operational reach: although the AD targets a single unit, those transponders are fitted across many light‑aircraft and helicopter types, concentrating compliance actions on numerous aircraft owners/operators.","Cross-reference to FAA AD increases regulatory alignment but adds an external normative source to the technical requirement."],"plain_english_summary":"This Airworthiness Directive requires replacing two resistor network modules (RM401 and RM402) in AlliedSignal KT 76A ATC transponders (specified part and serial number ranges) with glass‑coated parts under AlliedSignal Service Bulletin SB KT 76A‑7 (Mod 7). It applies to affected units before installation in an aircraft or by 10 September 1999 and became effective 10 September 1998. The FAA advised these transponders can transmit misleading encoded altimeter information; the directive therefore imposes parts-and-labour compliance costs on owners/operators and a firm deadline to follow the manufacturer’s modification procedure."},"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 Airworthiness Directive maintains its original narrow scope — addressing a specific safety defect in a specific transponder model. There is no evidence of scope creep; it remains targeted at the identified altitude-encoding fault."},"complexity_factors":["Single, specific technical requirement with clear part numbers and serial number ranges","Only one main compliance action required (replacement of two resistor modules)","Limited applicability — specific manufacturer, part numbers, and serial numbers listed","No nested exceptions or conditional logic; straightforward deadline","Short document with minimal cross-referencing (only one FAA directive mentioned for background)","No defined terms section or interpretive provisions"],"plain_english_summary":"CASA issued a safety order requiring owners/operators of certain Cessna, Piper, Beechcraft, Mooney, Twin Commander and McDonnell Douglas aircraft fitted with AlliedSignal KT 76A transponders to replace two resistor networks (RM401 and RM402).\n\nThe faulty parts caused incorrect altitude reports to ATC and TCAS, creating a safety risk; replacements must follow AlliedSignal Service Bulletin SB KT 76A-7 before installation and no later than 10 September 1999."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rad-63-kt-76a-atc-transponder","history":"/api/acts/ad-rad-63-kt-76a-atc-transponder/history","analysis":"/api/acts/ad-rad-63-kt-76a-atc-transponder/analysis","conflicts":"/api/acts/ad-rad-63-kt-76a-atc-transponder/conflicts","importantCases":"/api/acts/ad-rad-63-kt-76a-atc-transponder/important-cases","documents":"/api/acts/ad-rad-63-kt-76a-atc-transponder/documents"}}