{"id":"F2006B11157","name":"AD/LEARJET/5 - Airspeed - Machmeter Indicator Presentation - Modification","slug":"ad-learjet-5-airspeed-machmeter-indicator-presentation-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56851,"registerId":"commonwealth-F2006B11157-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LEARJET/5 - Airspeed - Machmeter Indicator Presentation - Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Gates Learjet 24 & 25 Series Aeroplanes\n\n \n\n# AD/LEARJET/5 Airspeed - Machmeter Indicator\n\nPresentation - Modification\n\nApplicability: Learjet Model 24D S/Nos. 266 and 279.\n\n# 6/74\n\n \n\nRequirement: Inspect and where necessary modify airspeed-machmeters to ensure that the Vmo limit is marked on the dial either by a red radial line at 306 knots for instruments without coloured sectors, or by a red arc extending from 306 knots to 700 knots for instruments with coloured sectors. All other limit marks or coloured sectors above 306 knots shall be removed.\n\n \n\nNote 1: Arrange with DoT to amend the Aircraft Flight Manual to comply with the aircraft installation if any change is necessary.\n\n \n\nNote 2: If the airspeed-machmeters have presentations identical to that shown on the Gates Learjet 24D Flight Manual Page 1-16 FAA-approved 6.25.70 Change 7, this page will be used in the Flight Manual. Such a presentation is without coloured sectors and has radial red lines at 306 knots and at .82 mach.\n\n \n\nCompliance: Within 300 hours time in service after 28 June 1974.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive affecting only two specific aircraft. It has not expanded beyond its original narrow purpose of correcting a specific instrument marking issue on specific serial numbers."},"complexity_factors":["Extremely short document (under 300 words)","Only 2 defined applicability criteria (specific aircraft serial numbers)","Single, straightforward mechanical requirement with two alternative compliance methods","No cross-references to other legislation or regulations beyond the enabling authority (Civil Aviation Regulations 1988, Part 39)","Simple conditional logic ('either/or' for instrument types)","Two non-binding notes providing supplementary guidance only"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of Learjet Model 24D serial numbers 266 and 279 inspect and, if necessary, modify their airspeed‑Machmeters so the maximum operating speed (Vmo) is clearly marked at 306 kt (red line or red arc) and any misleading markings above that speed are removed. It prevents pilots from inadvertently exceeding safe speeds; compliance was required within 300 flight hours after 28 June 1974."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive stays focused on ensuring correct Vmo presentation for the two listed aircraft. It does not broaden applicability to other models or add unrelated requirements; its measures are limited to instrument markings and associated AFM amendment."},"complexity_factors":["Very narrow applicability: only Learjet Model 24D, serial numbers 266 and 279.","Technical specificity: exact Vmo marking required (red radial line at 306 kt or red arc 306–700 kt).","Two instrument presentation variants (with or without coloured sectors) requiring distinct actions.","Removal of any existing limit marks/coloured sectors above 306 kt—possible need to alter or replace instrument faces.","Administrative step to amend Aircraft Flight Manual through the Department of Transport.","Fixed compliance metric: 300 hours time‑in‑service after a historical date, requiring tracking of flight hours.","Reference to an FAA‑approved Flight Manual page as an acceptable presentation creates an alternate compliance benchmark."],"plain_english_summary":"This airworthiness directive requires inspection and, if necessary, modification of the airspeed–machmeter on Learjet Model 24D serial nos. 266 and 279 so Vmo is clearly marked—either a red radial line at 306 kt (no coloured sectors) or a red arc from 306–700 kt (with coloured sectors); markings above 306 kt must be removed.\n\nCompliance is within 300 hours time‑in‑service after 28 June 1974; the aircraft owner/operator must carry out the work and arrange any Aircraft Flight Manual amendment with the Department of Transport."}},"importantCases":[],"_links":{"self":"/api/acts/ad-learjet-5-airspeed-machmeter-indicator-presentation-modification","history":"/api/acts/ad-learjet-5-airspeed-machmeter-indicator-presentation-modification/history","analysis":"/api/acts/ad-learjet-5-airspeed-machmeter-indicator-presentation-modification/analysis","conflicts":"/api/acts/ad-learjet-5-airspeed-machmeter-indicator-presentation-modification/conflicts","importantCases":"/api/acts/ad-learjet-5-airspeed-machmeter-indicator-presentation-modification/important-cases","documents":"/api/acts/ad-learjet-5-airspeed-machmeter-indicator-presentation-modification/documents"}}