{"id":"F2006B10031","name":"AD/G1159/29 - Flight Manual - Change to Metric Units","slug":"ad-g1159-29-flight-manual-change-to-metric-units","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55433,"registerId":"commonwealth-F2006B10031-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G1159/29 - Flight Manual - Change to Metric Units","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)  \nGulfstream (Grumman) G1159 and G-IV Series Aeroplanes\n\nAD/G1159/29 Flight Manual \\- Change to Metric Units 9/81\n\nApplicability: All Grumman G1159 Series Aeroplanes.\n\nRequirement: The D.o.T. approved flight manual shall be amended to specify quantities in the following units;\n\n    (a) weight in kilograms,\n\n    (b) distances in metres,\n\n    (c) centre of gravity limits and moment arms in millimetres,\n\n    (d) fuel and oil quantities in litres, and\n\n    (e) pressures in kilopascals.\n\nWhere the installed aircraft instrumentation is calibrated in units other than the above the flight manual shall specify both systems of units.\n\nCompliance: By 1 January 1984.\n\nBackground: It is required that all Australian aircraft be provided with airworthiness limitations and operational data in the declared metric units.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2090},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope of requiring metric unit conversion for flight manuals of specific Gulfstream aircraft types, with no expansion into broader operational restrictions or airworthiness engineering requirements."},"complexity_factors":["Single, unambiguous requirement with no cross-references to other legislation","Limited applicability to only one specific aircraft series (Grumman G1159)","Straightforward list of five unit conversions with no conditional logic","Only one simple exception clause regarding dual-unit display","No defined terms, interpretation sections, or subordinate provisions"],"plain_english_summary":"This safety directive requires owners and operators of **Grumman G1159 series aircraft** (Gulfstream II, III, and IV business jets) to rewrite their flight manuals—the handbooks pilots rely on for safe operation—using metric units instead of imperial measurements.\n\n**Specific changes required:**\n- Aircraft **weight** limits must be listed in **kilograms**\n- **Distances** (such as runway requirements) in **metres**\n- **Balance limits** (centre of gravity) and related measurements in **millimetres**\n- **Fuel and oil** volumes in **litres**\n- **Pressure** readings in **kilopascals**\n\n**Exception:** If the aircraft's cockpit instruments still display imperial units (such as pounds or gallons), the flight manual must show both metric and imperial figures side-by-side.\n\n**Deadline:** Operators were required to comply by **1 January 1984**.\n\nThis change ensured that all Australian aviation safety data used the national metric standard, reducing the risk of dangerous calculation errors caused by mixing measurement systems during flight planning or refuelling."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g1159-29-flight-manual-change-to-metric-units","history":"/api/acts/ad-g1159-29-flight-manual-change-to-metric-units/history","analysis":"/api/acts/ad-g1159-29-flight-manual-change-to-metric-units/analysis","conflicts":"/api/acts/ad-g1159-29-flight-manual-change-to-metric-units/conflicts","importantCases":"/api/acts/ad-g1159-29-flight-manual-change-to-metric-units/important-cases","documents":"/api/acts/ad-g1159-29-flight-manual-change-to-metric-units/documents"}}