{"id":"F2009L01502","name":"AD/RAD/89 - Funwerk Avionics GmbH TRT800A and TRT800H Transponders","slug":"ad-rad-89-funwerk-avionics-gmbh-trt800a-and-trt800h-transponders","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":78113,"registerId":"commonwealth-F2009L01502-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Radio Communication and Navigation Equip","sectionType":"division","heading":"Radio Communication and Navigation Equipment","content":"### Radio Communication and Navigation Equipment\n\n| AD/RAD/89 | Funwerk Avionics GmbH TRT800Aand TRT800H Transponders | 5/2009 |\n| --------- | ----------------------------------------------------- | ------ |\n\n```html\n

Applicability:

Mode-S transponders manufactured by Funkwerk Avionics GmbH (formerly Filser Electronic GmbH), except those marked Mod-Index 10 as follows:

- Model TRT800A, all part numbers (P/N), serial numbers (S/N) up to and including 40539908, and

- Model TRT800H, all P/N, S/N up to and including 30250007.

Note 1: These transponders are known to be installed on, but not limited to, the following aircraft types:

Manufacturer

Model

APEX (Robin)
Cessna (including Reims Aviation in France)
Diamond Aircraft Industries
Extra
Grob
Mooney
Piper
Scheibe
True Flight Holdings (Grumman, American)

DR1050, DR250, DR350 and DR400 series
150, 172, 182, 210, T303 and 337 series

DV 20
EA-300 series
G 109 B powered sailplane and G 115 series
M20J
PA-28 series
SF 25 C Powered Sailplanes
AA-5B

Requirement:

1. Replace the affected transponder with a unit that has been modified in accordance with Funkwerk Avionics Service Bulletin (SB) TRT800-A-H-1 Revision 1.04 dated 17 October 2008 or later revision approved by the European Aviation Safety Agency (EASA).

2. Transponders, as identified in the Applicability Statement, may not be installed on any aircraft, unless it has been modified in accordance with SB
TRT800-A-H-1 Revision 1.04 or later revision approved by the EASA.

Note 2: EASA AD 2008-0183 refers.

Compliance:

For Requirement 1 - Before 19 November 2010.

\n```\n\n| | For Requirement 2 - After 18 November 2010. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Airworthiness Directive becomes effective on 7 May 2009. |\n| Background: | EASA has received reports of intermittent loss of detection on Mode-S Secondary Surveillance Radar (SSR) of aircraft equipped with Funkwerk Avionics TRT800A Transponders. Reports from Air Navigation Service Providers (ANSP), as well as data from flight trials, have shown that the unit fails to perform as expected.Based on the information provided in the reports, EASA has determined that operation of these transponders in airspace where Mode S interrogations are used by the ground systems could create disruptions in the Air Traffic Management process, potentially compromising aircraft safety. |\n| | Whilst very fewTRT800 transponders are known to be in Australia, CASA has decided to issue this Directive which requires the modification of affected transponders and limits there installation in aircraft after 18 November 2010. |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n26 March 2009","sortOrder":0},{"sectionNumber":"AD/RAD/89","sectionType":"part","heading":"AD/RAD/89","content":"## AD/RAD/89","sortOrder":1},{"sectionNumber":"Funwerk Avionics GmbH TRT800Aand TRT800H","sectionType":"part","heading":"Funwerk Avionics GmbH TRT800Aand TRT800H Transponders","content":"## Funwerk Avionics GmbH TRT800A \nand TRT800H Transponders","sortOrder":2},{"sectionNumber":"5/2009","sectionType":"part","heading":"5/2009","content":"## 5/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope aligns with the EASA action cited in the Directive. CASA adopted the EASA-identified applicability, required modification per SB TRT800‑A‑H‑1 Revision 1.04 (or later EASA‑approved revision), and imposed the installation prohibition after 18 November 2010. No expansion of affected equipment or additional requirements beyond the EASA-referenced measures is evident in the source text."},"complexity_factors":["Narrow technical focus: single equipment type (TRT800A/TRT800H) and specific serial-number ranges (Applicability).","Mandatory compliance tied to a manufacturer Service Bulletin and requires EASA approval for later revisions (Requirement 1).","Two-step regime: modify/replace by a fixed date and prohibition on installing unmodified units after a later date (Compliance; Requirement 2).","Cross-reference to EASA AD 2008-0183 — dependence on overseas regulator's findings and approvals (Note 2; Background).","Operational impact concentrated on aircraft/operators that actually have these units; few units known in Australia (Background).","Clear allocation of costs and decision authority: operators bear modification/replacement costs; CASA/EASA control approval and compliance enforcement (Applicability; Requirement; Compliance)."],"plain_english_summary":"This Directive requires operators to modify or replace Funkwerk (formerly Filser) TRT800A and TRT800H Mode‑S transponders (specified serial ranges) in accordance with Funkwerk Service Bulletin TRT800‑A‑H‑1 Revision 1.04 or a later EASA‑approved revision; unmodified units may not be installed after 18 November 2010. It affects aircraft fitted with these transponders (examples are listed) because EASA reported intermittent loss of Mode‑S detection that can disrupt air traffic surveillance. Operators pay for modification or replacement; CASA and EASA set the approvals and deadlines."},"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":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific safety defect in specific equipment. The scope remains precisely limited to the identified transponder models and has not expanded beyond the original safety purpose."},"complexity_factors":["Single, clearly defined applicability section with specific model numbers and serial number cut-offs","Two straightforward compliance requirements with hard deadlines","Minimal cross-referencing (only one external reference to EASA AD 2008-0183 and manufacturer service bulletin)","No nested conditional logic or exceptions to exceptions","Technical but narrow scope — applies only to specific aviation equipment","Clear effective date and compliance timeline structure"],"plain_english_summary":"This Airworthiness Directive requires owners/operators to modify or replace certain Funkwerk (formerly Filser) Mode‑S TRT800A/H transponders because they can intermittently fail to respond to ground radar, making aircraft effectively “invisible.” It affects many light aircraft (Cessna, Piper, Mooney, Diamond, powered gliders) fitted with affected serial-numbered units. A compliance deadline and a ban on installing unmodified units ensure the safety risk to air traffic management is eliminated."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rad-89-funwerk-avionics-gmbh-trt800a-and-trt800h-transponders","history":"/api/acts/ad-rad-89-funwerk-avionics-gmbh-trt800a-and-trt800h-transponders/history","analysis":"/api/acts/ad-rad-89-funwerk-avionics-gmbh-trt800a-and-trt800h-transponders/analysis","conflicts":"/api/acts/ad-rad-89-funwerk-avionics-gmbh-trt800a-and-trt800h-transponders/conflicts","importantCases":"/api/acts/ad-rad-89-funwerk-avionics-gmbh-trt800a-and-trt800h-transponders/important-cases","documents":"/api/acts/ad-rad-89-funwerk-avionics-gmbh-trt800a-and-trt800h-transponders/documents"}}