{"id":"F2005B00781","name":"Civil Aviation Amendment Order (No. R6) 2004 - Civil Aviation Order 20.7.1 - Aeroplane weight limitations - Aeroplanes above 5 700kg - All operations (piston-engined) (02/12/2004)","slug":"civil-aviation-amendment-order-no-r6-2004-civil-aviation-order-20-7-1-aeroplane-weight-limitations-a","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":32212,"registerId":"commonwealth-F2005B00781-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"part","heading":"APPLICATION","content":"# 1 APPLICATION\n\nThis section applies to piston-engined aeroplane types having a maximum permissible all-up weight in excess of 5 700 kg and which were registered in Australia prior to 1 June 1963.\n\n2 TAKE-OFF WEIGHT LIMITATIONS\n\n2.1 An aeroplane shall not take-off at a weight in excess of the weights determined in accordance with subparagraphs 2.1.1 to 2.1.4 of these Orders:\n\n2.1.1 The permissible all-up weight as specified in its Certificate of Airworthiness.\n\n2.1.2 The maximum take-off weight specified in the relevant Aeroplane Flight Manual for the altitude above sea level of the aerodrome concerned.\n\n2.1.3 The lesser weight of either:\n\n    (a) the permissible landing weight at the destination aerodrome calculated in accordance with paragraph 3 of these Orders plus the weight of fuel that would normally be consumed in flying from the departure aerodrome to the destination aerodrome; or\n    (b) the permissible landing weight at the alternate aerodrome calculated in accordance with paragraph 3 of these Orders plus the weight of fuel that would normally be consumed in flying from the departure aerodrome to the alternate aerodrome.\n\n> Note: Subparagraph (b) will apply only when the flight plan includes an alternate aerodrome.\n\n2.1.4 The weight calculated from the relevant current CASA Take-off Weight Chart or approved Company Take-off Weight Chart for the aerodrome type concerned in conjunction with either:\n\n    (a) the corrected effective operational length of the runway to be used for take-off under ambient conditions; or\n    (b) the appropriate seasonal declared density altitude taken in conjunction with either:\n\n(i) the corrected effective operational length of the runway for take-off under no wind conditions; or\n\n(ii) the corrected effective operational length of any subsidiary runway for take-off under the minimum head-wind component that may result when the main runway cannot be used due to excessive cross-wind component, whichever gives the lesser weight.\n\n> Note: The weight calculated in accordance with subparagraph (b) (ii) above shall not apply to a subsidiary runway which is listed in the Operations Manual as being unsuited for take-off by the type of aeroplane concerned when using declared weight. When it is desired to use a subsidiary runway which has been so listed in the Operations Manual the take-off weight shall be calculated using the methods specified in subparagraph (a) of this paragraph.\n\n2.2 Where, prior to the take-off, a significant change occurs in the value of any factor used in computing the permissible take-off weight which would have the effect of requiring a reduced all-up weight from that already computed, then a new all-up weight shall be calculated using the new value for the factor(s) concerned and the weight so determined shall be the maximum weight to be used for take-off.\n\n2.3 Take-off weight charts which enable compliance with this Order are available on application to CASA. Instructions for the use of these charts are provided at Appendix 1.\n\n3 LANDING WEIGHT LIMITATIONS\n\n3.1 Except in an emergency, an aeroplane shall not land at a weight in excess of the least of the weights determined in accordance with subparagraphs 3.1.1 to 3.1.3 of these Orders.\n\n3.1.1 The maximum permissible landing weight as specified in its Certificate of Airworthiness.\n\n3.1.2 The maximum landing weight specified in the relevant Aeroplane Flight Manual for the altitude above sea level of the aerodrome concerned.\n\n3.1.3 The weight calculated from the relevant CASA Landing Weight Chart or the approved Company Landing Weight Chart for the aeroplane type concerned in conjunction with the forecast pressure and temperature or the appropriate seasonal declared density altitude with either:\n\n    (a) the corrected effective operational length of the main runway for landing under no wind conditions; or\n    (b) the corrected effective operational length of a subsidiary runway for landing under the minimum head-wind component that may result when the main runway cannot be used due to excessive cross-wind component, whichever give the lesser weight.\n\n> Note: The weight limitation calculated in accordance with subparagraph (b) above shall not apply to a subsidiary runway which is listed in the Operations Manual as being unsuited for landings for the type of aeroplane concerned.\n\n3.2 Landing weight charts which enable compliance with this Order are available on application to CASA. Instructions for the use of these charts are provided at Appendix 2.\n\n  \nAPPENDIX 1\n\nCASA TAKE-OFF WEIGHT CHARTS — P SERIES —\n\nINSTRUCTIONS FOR USE\n\n1 Under Ambient Conditions:\n\n1.1 Set altimeter on 29.92 inches Hg or 1013.2 millibars and read the pressure altitude of the aerodrome.\n\n1.2 Apply this altitude to the pressure altitude in feet co-ordinate on the relevant take-off weight chart. Move vertically to intersect the temperature line representing the ambient temperature. This temperature shall be obtained from the aerodrome meteorological station.\n\n> Note: When there is no aerodrome meteorological station the reading of the aeroplane outside air temperature indicator may be used.\n\n1.3 From this point move horizontally to intersect the corrected effective operational length available for take-off.\n\n1.4 Move vertically downwards to intersect the head-wind component line at a point corresponding to the ambient head-wind component.\n\n1.5 Move horizontally and read take-off weight. Record the weight thus obtained.\n\n1.6 Ascertain the elevation of the aerodrome.\n\n1.7 Apply this elevation to the elevation of aerodrome co-ordinate. Move vertically to intersect the take-off climb limitation line.\n\n1.8 From this point move horizontally and read the take-off weight. Record the weight thus obtained.\n\n1.9 The maximum permissible take-off weight shall be the lesser of the 2 weights as determined in paragraphs 1.5 and 1.8 above.\n\n1.10 The take-off weight as obtained by the foregoing method shall apply only where the aeroplane is to be flown in the configuration specified in the relevant Take-off Weight Chart and with the engine power specified therein. The use of any other configuration or engine power is prohibited except where an application to use some other condition has been made to CASA and it has approved such condition.\n\n1.11 For purpose of take-off weight computations, head-wind components in excess of 20 knots shall be deemed to be 20 knots.\n\n2 Under Declared Conditions:\n\n2.1 Use the appropriate seasonal Declared Density Altitude Chart, and add the elevation of the aerodrome concerned to the value read from the chart and thus obtain the declared seasonal density altitude.\n\n2.2 Apply the declared seasonal density altitude to the density altitude co-ordinate of the take-off weight chart. Move horizontally to intersect the corrected effective operational length line corresponding to the corrected effective operational length available for take-off.\n\n2.3 Move vertically downwards to intersect the zero head-wind component line.\n\n2.4 From this point move horizontally read the take-off weight. Record the weight thus obtained.\n\n2.5 Apply the valuation of the elevation of the aerodrome to the aerodrome elevation co-ordinate. Move vertically to intersect the take-off climb limitation line.\n\n2.6 From this point move horizontally and read the all-up weight. Record the weight thus obtained.\n\n2.7 The maximum permissible take-off weight shall be the lesser of the 2 weights as determined in paragraphs 2.4 and 2.6 above.\n\n2.8 The take-off weight as obtained by the foregoing method shall apply only where the aeroplane is to be flown in the configuration specified in the relevant Take-off Weight Chart and with the engine power specified therein. The use of any other configuration or engine power is prohibited except where an application to use some other condition has been made to CASA and it has approved such condition.\n\n  \nAPPENDIX 2\n\nCASA LANDING WEIGHT CHARTS — P SERIES —\n\nINSTRUCTIONS FOR USE\n\n1 Under Ambient Conditions:\n\n1.1 Obtain the forecast temperature and pressure altitude for the destination aerodrome.\n\n1.2 Apply the pressure altitude to the pressure altitude in feet co-ordinate on the chart. Move vertically to intersect the temperature line representing the forecast temperature.\n\n1.3 From this point move horizontally to intersect the corrected effective operational length to the corrected effective operational length available for landing.\n\n1.4 Move vertically downwards and read take-off weight. Record the weight thus obtained.\n\n1.5 Ascertain the elevation of the aerodrome.\n\n1.6 Apply this elevation to the aerodrome elevation co-ordinate. Move vertically to intersect the landing climb limitation line.\n\n1.7 From this point move horizontally and read the landing weight. Record the weight thus obtained.\n\n1.8 The maximum permissible landing weight is the lesser of the 2 weights as determined in paragraphs 1.4 and 1.7 above.\n\n1.9 The landing weight as obtained by the foregoing method shall apply only when the aeroplane is to be flown in the configuration specified in the relevant Landing Chart. The use of any other configuration is prohibited except where an application to use some other condition has been made to CASA and it has approved such condition.\n\n1.10 When it is necessary to specify an alternate aerodrome, the above procedure shall be repeated for that aerodrome.\n\n2 Under Declared Conditions:\n\n2.1 Use the appropriate seasonal Declared Density Altitude Chart, and add the elevation of the destination aerodrome to the value(s) read from the chart and thus obtain the declared seasonal density altitude.\n\n2.2 Apply the declared seasonal density altitude to the density altitude co-ordinate of the landing weight chart. Move horizontally to intersect the corrected effective operational length line corresponding to the corrected effective operational length available for landing.\n\n2.3 Move vertically downwards and obtain the landing weight. Record the weight thus obtained.\n\n2.4 Ascertain the elevation of the destination aerodrome.\n\n2.5 Apply this elevation to the aerodrome elevation co-ordinate. Move vertically to intersect the landing climb limitation line.\n\n2.6 From this point move horizontally and read the landing weight. Record the weight thus obtained.\n\n2.7 The maximum permissible landing weight shall be the lesser of the 2 weights as determined in paragraphs 2.3 and 2.6 above.\n\n2.8 The landing weight as obtained by the foregoing method shall apply only where the aeroplane is to be flown in the configuration specified in the relevant Landing Chart. The use of any other configuration is prohibited except where an application to use some other condition has been made to CASA and it has approved such condition.","sortOrder":0}],"analysis":{"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"},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"This instrument is a technical, procedural specification rather than a change of regulatory reach. It confines its application to a narrowly defined historic class of aircraft (piston‑engined types >5,700 kg registered before 1 June 1963) and prescribes calculation methods, chart usage and conditions for take‑off and landing weights. Compared with the original purpose (setting safe operational weight limits and how to compute them), the 2004 text does not materially widen the population of regulated aircraft or add new substantive regulatory powers; it formalises methods, chart use and approval processes. Any expansion is procedural (specifying CASA and approved Company charts and adding worked procedures in appendices) rather than a change in scope of who or what is regulated."},"complexity_factors":["Narrow scope defined by aircraft type and registration date (s.1) but multiple calculation pathways (take‑off vs landing)","Multiple external cross‑references: Certificate of Airworthiness, Aeroplane Flight Manual, Operations Manual, CASA or approved Company charts","Nested conditional logic in take‑off chart method (s.2.1.4(b)(ii)) and subsidiary runway exceptions (notes to s.2.1.4 and s.3.1.3)","Two distinct regimes for charts: ambient conditions and declared (seasonal) density altitude, each with multi‑step procedures in Appendices 1 & 2","Dynamic recalculation requirement if factors change before take‑off (s.2.2)","Operational caps and limits embedded in appendices (e.g. headwind capped at 20 knots, specific altimeter/pressure settings)","Approval gateways and prohibitions on non‑standard configurations unless CASA approves (s.2.1.10, appendices)","Emergency exception for landing weights adds an override to otherwise strict limits (s.3.1)"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Applies to piston‑engined aeroplane types with a maximum permissible all‑up weight (take‑off weight) over 5,700 kg that were registered in Australia before 1 June 1963 (s.1).\n\n- Prescribes hard limits and the exact methods for calculating maximum permissible take‑off weight (s.2) and maximum permissible landing weight (s.3). Operators must use the lowest weight produced by the applicable tests and charts; the instrument sets out which tests/charts to compare.\n\n- Allows operators to use either the relevant CASA charts or an approved Company chart for take‑off and landing calculations, and requires CASA approval for any use of configurations or engine powers other than those specified on the charts (s.2.1.4, s.2.1.10, s.3.1.3, appendices).\n\n- Requires recalculation of the permitted take‑off weight if, before take‑off, any factor used in the original computation changes significantly so that a lower weight would be required (s.2.2).\n\n- Provides detailed step‑by‑step procedures (in Appendix 1 and Appendix 2) for using the CASA take‑off and landing weight charts under two regimes: ambient conditions (using actual pressure altitude, temperature, headwind, runway length, etc.) and declared conditions (seasonal declared density altitude plus aerodrome elevation). The appendices cover how to read charts, where to cap headwind values, and how to treat subsidiary runways and climb limitations.\n\n- Contains a landing exception for emergencies: except in an emergency an aeroplane shall not land above the prescribed limits (s.3.1).\n\n\n**Who this affects**\n\n- Operators, pilots and flight dispatchers of the specified older, large piston‑engined aeroplane types (registered in Australia before 1 June 1963) — they must perform the specified weight calculations and comply with the lowest applicable limit (s.1, s.2, s.3).\n- Organisations that prepare aeronautical documentation and operations manuals (they may need to list subsidiary runways as unsuitable, see notes in s.2.1.4 and s.3.1.3).\n- CASA, which supplies the official charts and must approve non‑standard configurations, company charts and any departures from chart configurations (s.2.1.4, s.2.1.10, appendices).\n\n\n**Why it matters (practical effects and operational mechanics)**\n\n- Safety envelope and performance: the Order translates structural/performance limits (Certificate of Airworthiness, Aeroplane Flight Manual (AFM)) into operational limits for take‑off and landing at particular aerodromes and ambient conditions (s.2.1.1, s.2.1.2, s.3.1.1, s.3.1.2).\n\n- Payload and fuel planning: because the permissible take‑off weight is the least of several computed values (including landing requirements plus fuel to destination/alternate), operators may need to reduce payload or fuel, select different runways, or choose different alternates to stay within limits (s.2.1.3–2.1.4; note to s.2.1.3).\n\n- Administrative control and discrete approvals: CASA supplies official charts and must approve any deviation from chart configuration or power settings, giving CASA decision‑making authority over operational exceptions (s.2.1.10, appendices).\n\n- Operational contingency: the Order requires recalculation if conditions change before take‑off (s.2.2), and it restricts use of subsidiary runways when an operator’s Operations Manual lists them as unsuitable (notes to s.2.1.4 and s.3.1.3). These rules change behaviour: crews must re‑check weights, possibly offload or delay flights, and consult Operations Manual listings.\n\n\n**Costs, incentives, trade‑offs and practical risks**\n\n- Who pays: operators bear the immediate costs — calculating weights, possibly carrying less payload or conducting extra flights, or applying for CASA approvals when non‑standard configurations are desired (s.2.1.10, appendices).\n\n- Incentives and substitution: the rules create incentives to choose runways, alternates and seasons that permit higher payloads, or to seek CASA approval for company charts/configurations that allow more favourable weights (s.2.1.4; s.2.1.10).\n\n- Administrative burden and discretion: CASA’s role in approving alternative charts or configurations introduces an administrative step and discretionary decision‑making; operators must maintain and justify company charts if they use them (s.2.1.4, appendices).\n\n- Implementation risks: accuracy of meteorological inputs, correct reading of charts, and timely recalculation when factors change are necessary for compliance; the Order caps headwind benefits at 20 knots for take‑off chart calculations (Appendix 1.1.11), which affects computations.\n\n- Coverage is narrow: only older piston‑engined aeroplanes above 5,700 kg registered before 1 June 1963 fall within the rule (s.1), so the operational and economic impacts are concentrated on a small group of operators rather than broadly distributed.\n\n\n**Key cross‑references inside the instrument**\n\n- Primary limits drawn from Certificate of Airworthiness and Aeroplane Flight Manual are referenced repeatedly (s.2.1.1, s.2.1.2, s.3.1.1, s.3.1.2).\n- CASA and approved Company take‑off/landing charts are the calculation tools (s.2.1.4, s.3.1.3; Appendices 1 and 2).\n- Operations Manual listings can exclude subsidiary runway calculations (notes to s.2.1.4 and s.3.1.3).\n\n\n**Practical checklist for an operator/pilot**\n\n- Confirm aircraft type and registration date fall under s.1.\n- Before dispatch, calculate permissible take‑off weight using the four tests in s.2.1 and take the lowest value.\n- If conditions change materially before take‑off, re‑calculate (s.2.2).\n- For landing, compute weights as in s.3.1 and use the lesser of the values; only in an emergency may you exceed these limits (s.3.1).\n- Use CASA charts or an approved Company chart and follow the step‑by‑step methods in Appendices 1 and 2; obtain CASA approval for non‑standard configurations.\n\n(References in parentheses refer to sections and paragraphs of the Order supplied.)"},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":false,"description":"This legislation maintains its original narrow scope. It targets a specific, limited category of aircraft (piston-engined aeroplanes over 5,700kg registered before 1963) and provides detailed operational rules for that category only. The detailed appendices with chart instructions are integral to the original purpose of ensuring safe weight calculations, not an expansion beyond the original intent."},"complexity_factors":["Multiple nested calculation methods with cross-references between take-off and landing sections (paragraph 2.1.3 references paragraph 3 calculations)","Dual calculation systems: 'ambient conditions' vs 'declared conditions' requiring different chart types","Extensive conditional logic with 'whichever gives the lesser weight' clauses appearing 3 times","Specific exceptions to exceptions regarding subsidiary runways (Operations Manual exclusions in Notes to paragraphs 2.1.4 and 3.1.3)","Technical aviation terminology requiring domain knowledge: 'corrected effective operational length', 'density altitude', 'pressure altitude', 'head-wind component'","Appendices contain 19 numbered procedural steps across two calculation methods","Cross-references between main Order and Appendices (paragraph 2.3 references Appendix 1, paragraph 3.2 references Appendix 2)","Temporal limitation creating a specific regulated class: aircraft registered before 1 June 1963 only"],"plain_english_summary":"This legislation sets strict weight limits for older, heavy piston-engine aeroplanes (over 5,700 kg) that were registered in Australia before June 1963. It tells pilots and operators exactly how to calculate the maximum weight allowed for take-off and landing based on runway length, weather conditions, altitude, and aircraft specifications.\n\n**Who it affects:**\n- Operators of vintage piston-engine aeroplanes over 5,700 kg (roughly the weight of a large truck)\n- Pilots flying these specific aircraft types\n- Civil Aviation Safety Authority (CASA) staff who approve weight charts\n\n**What it requires:**\n\n**For take-off:**\n- The plane cannot exceed the weight listed on its Certificate of Airworthiness (official document proving the aircraft is safe to fly)\n- The weight must suit the airport's altitude\n- The pilot must account for fuel burned during flight when calculating landing weight at the destination\n- Weight must be calculated using official CASA charts that factor in:\n  - Runway length available\n  - Temperature and air pressure (density altitude)\n  - Wind conditions\n  - Whether using the main runway or a shorter backup runway\n\n**For landing:**\n- Similar calculations using landing-specific charts\n- Emergency landings are the only exception to weight limits\n\n**Why it matters:**\nThese older piston-engine aircraft have less power and different performance characteristics than modern jets. The rules prevent accidents caused by overloaded planes trying to take off from short runways or in hot weather (which reduces engine performance and wing lift). The detailed charts and calculations ensure pilots don't exceed safe operating limits."}},"importantCases":[],"_links":{"self":"/api/acts/civil-aviation-amendment-order-no-r6-2004-civil-aviation-order-20-7-1-aeroplane-weight-limitations-a","history":"/api/acts/civil-aviation-amendment-order-no-r6-2004-civil-aviation-order-20-7-1-aeroplane-weight-limitations-a/history","analysis":"/api/acts/civil-aviation-amendment-order-no-r6-2004-civil-aviation-order-20-7-1-aeroplane-weight-limitations-a/analysis","conflicts":"/api/acts/civil-aviation-amendment-order-no-r6-2004-civil-aviation-order-20-7-1-aeroplane-weight-limitations-a/conflicts","importantCases":"/api/acts/civil-aviation-amendment-order-no-r6-2004-civil-aviation-order-20-7-1-aeroplane-weight-limitations-a/important-cases","documents":"/api/acts/civil-aviation-amendment-order-no-r6-2004-civil-aviation-order-20-7-1-aeroplane-weight-limitations-a/documents"}}