{"id":"F2006B06515","name":"AD/RAD/60 Amdt 1 - GNS-XLS/GNS-XL Warning Placard","slug":"ad-rad-60-amdt-1-gns-xls-gns-xl-warning-placard","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48113,"registerId":"commonwealth-F2006B06515-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RAD/60 Amdt 1 - GNS-XLS/GNS-XL Warning Placard","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/60\n\nAmdt 1\n\n  \nGNS-XLS/GNS-XL Warning Placard 1/98\n\nApplicability: All aircraft fitted with ALLIED SIGNAL AVIONICS INC (GLOBAL WULFBERG) global positioning systems (GPS) Flight Management Systems Model GNS-XLS and GNS-XL Part No. 17960-0102-XXXX and Part No. 18355-0101-XXXX.\n\nNote: This equipment is fitted to but not limited to:\n\nBritish Aerospace, Ltd, Model 146-100A and 146-200A Cessna Aircraft Corporation, Model 525, 550 and 560\n\nDassault Aviation, Mystere-Falcon 20 and 50 Avions Marcel Dassault, Falcon 10\n\nGulfstream Aerospace, Models G-1159 (GII) and G-1159A (GIII) Raytheon Corporate Jets, Hawker 800\n\nIsrael Aircraft Industries, Ltd, Model 1124 and 1125 Sabreliner Corporation, Model NA-65\n\nLearjet Inc, Model 35\n\nJetstream Aircraft Ltd, Model 4101\n\nRequirement: Determine the modification status of the installed software in accordance with Allied Signal Software Bulletin SWB GNS-XL\\-SW1 or SWB GNS-XLS\\-SW1. If software modification 2 is installed no further action is required, otherwise either:\n\n    Fabricate a placard, with the following words in letters at least 2.5mm (0.10 inches) in height and install the placard in clear view of the pilot on the instrument panel:\n\nGPS NPA LIMITED TO TRAINING IN DAY VMC ONLY\n\nor\n\n    b. Install software modification number 2 in accordance with Allied Signal Software Bulletin SWB GNS-XL\\-SW1 or SWB GNS-XLS\\-SW2.\n\nNote: FAA AD 97-05-03 Amdt 39-9947 refers.\n\nInstallation of Software Modification number 2 comprises terminating action for this AD, and the placard, if installed, can be removed when Software Modification number 2 is installed.\n\nCompliance: Prior to 27 February 1998.\n\nThis amendment becomes effective on 1 January 1998.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: FAA has reported that the GNS-XLS or GNS-XL may generate misleading information during non-precision GPS approaches or Overlay approaches due to software limitations. Allied Signal has developed a modification which is an acceptable means of compliance for this AD.\n\nThe original issue of this airworthiness directive became effective on 16 April 1997.","sortOrder":0}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment stays within the original safety‑focused purpose: to mitigate a specific software‑related hazard in specified Allied Signal GPS/FMS units. It does not broaden the rule to unrelated equipment, new operational domains, or additional obligations beyond requiring either a temporary operational limitation (placard) or installation of a corrective software modification. The amendment clarifies compliance options and makes the software modification the terminating action, but it does not materially change the underlying scope of the directive from its original safety objective."},"complexity_factors":["Short, single‑issue airworthiness directive (few pages)","One defined equipment cohort (GNS‑XLS/GNS‑XL) rather than broad classes","Two explicit compliance options (placard or software mod) — simple conditional","Cross‑references to external manufacturer documents (SWB GNS‑XL/SWB GNS‑XLS) and an FAA AD","One clear terminating action (installation of software modification 2)","Fixed compliance/effective dates (simple timing rules)","No nested exceptions or multiple tiers of penalties or approvals"],"plain_english_summary":"**What this instrument does (mechanics):**\n\n- Applies to all aircraft fitted with Allied Signal Avionics (Global Wulfberg) GPS/FMS units Model GNS‑XLS and GNS‑XL (part numbers 17960‑0102‑XXXX and 18355‑0101‑XXXX). (See \"Applicability\".)\n- Requires operators/owners to check which software modification is installed in the unit by following Allied Signal Software Bulletin SWB GNS‑XL‑SW1 or SWB GNS‑XLS‑SW1. (See \"Requirement\".)\n- If \"software modification 2\" is already installed, no further action is required.\n- If software modification 2 is not installed, the operator must do one of two things before 27 February 1998: either\n  - fit a pilot‑visible placard on the instrument panel that reads \"GPS NPA LIMITED TO TRAINING IN DAY VMC ONLY\" (letters at least 2.5 mm high), or\n  - install software modification 2 in accordance with the Allied Signal software bulletin. (See \"Requirement\".)\n- Installing software modification 2 is the terminating action for the directive; if the placard was fitted earlier, it can be removed once the software is installed.\n\n**Who it affects:**\n\n- Aircraft owners/operators whose aircraft carry the specified Allied Signal GNS‑XLS or GNS‑XL GPS/FMS units. The directive lists common airframes that use these units (e.g. certain British Aerospace, Cessna, Dassault, Gulfstream, Raytheon, Learjet, Jetstream models), but the applicability is to the equipment, not only those airframes. (See \"Applicability\" and the note listing types.)\n\n**Why it matters (official rationale and concrete safety problem):**\n\n- The FAA reported that the GNS‑XLS/GNS‑XL software can give misleading guidance during non‑precision GPS approaches or GPS Overlay approaches because of software limitations. Allied Signal developed a software modification to correct the problem. (See \"Background\".)\n- The directive forces a short‑term operational restriction (placard limiting GPS non‑precision approaches to day Visual Meteorological Conditions for training only) unless the corrective software is installed. That restriction reduces the risk that pilots will follow misleading GPS guidance during the relevant instrument approaches.\n\n**Costs, incentives and trade‑offs (practical testing of the stated purpose):**\n\n- Who pays: aircraft owners/operators pay any costs — either a trivial cost to fabricate and install the placard or the direct costs of obtaining and installing the software modification (parts, labour, possible avionics shop time and aircraft downtime). (See \"Requirement\".)\n- Behaviour changes required: until the software fix is installed, operators must either restrict GPS use for non‑precision approaches (by posting the placard) or invest in the software modification. That creates an operational choice: accept a flight‑use limitation or pay for the modification.\n- Compliance burden: low if the placard route is taken (simple fabrication and installation); moderate if the software modification is required (technical installation, potential bench or shop time). The AD gives two clear compliance paths and defines the modification as terminating action, which simplifies ongoing compliance obligations.\n- Implementation risk: depends on the availability of the Allied Signal software bulletin and qualified installers. The AD cross‑references external manufacturer documentation (SWB GNS‑XL/GNS‑XLS) and an FAA AD, so effective compliance requires access to those documents and certified avionics work.\n- Substitution effects: some operators may defer the software modification and fly under the placard restriction to avoid immediate costs, producing a temporary concentrate of risk (aircraft operating with a limitation rather than corrected software).\n- Concentrated benefits/costs: the safety benefit (reduced risk of misleading guidance) is broadly distributed to airspace users and passengers; the cost is concentrated on the operators of affected aircraft.\n\n**Implementation detail that matters:** the AD sets a hard compliance date (prior to 27 February 1998) and states the AD becomes effective 1 January 1998. The placard specification (minimum letter height) and the software bulletin references are binding parts of compliance. (See \"Compliance\" and \"Requirement\".)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is an amendment (Amdt 1) to an existing Airworthiness Directive. The scope remains tightly focused on the original safety issue regarding misleading GPS approach data. The amendment appears to clarify or update the original directive (effective April 1997) without expanding beyond the specific Allied Signal GNS-XLS/XL systems and the original safety concern."},"complexity_factors":["Single, specific technical issue with clear binary compliance path (placard OR software upgrade)","Only 2 defined model numbers and straightforward applicability criteria","Simple conditional logic: check software version → if not Mod 2, take action","No nested exceptions or cross-references to other legislation","Clear compliance deadline and effective date","Background explanation included for context"],"plain_english_summary":"This safety notice warns that Allied Signal (Honeywell) GNS-XLS/GNS-XL GPS units can give wrong or misleading data on certain GPS approaches, risking unsafe landings. It affects aircraft fitted with these units (examples: BAe 146, Cessna Citation series, Falcon, Gulfstream II/III, Learjet 35).\n\nBy 27 Feb 1998 owners/operators must either install a cockpit placard limiting GPS non‑precision approaches to day VMC training only, or upgrade software (Mod 2) to permanently fix the fault."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rad-60-amdt-1-gns-xls-gns-xl-warning-placard","history":"/api/acts/ad-rad-60-amdt-1-gns-xls-gns-xl-warning-placard/history","analysis":"/api/acts/ad-rad-60-amdt-1-gns-xls-gns-xl-warning-placard/analysis","conflicts":"/api/acts/ad-rad-60-amdt-1-gns-xls-gns-xl-warning-placard/conflicts","importantCases":"/api/acts/ad-rad-60-amdt-1-gns-xls-gns-xl-warning-placard/important-cases","documents":"/api/acts/ad-rad-60-amdt-1-gns-xls-gns-xl-warning-placard/documents"}}