{"id":"F2006B02543","name":"AD/AT/14 - Never Exceed Airspeed Limit","slug":"ad-at-14-never-exceed-airspeed-limit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41799,"registerId":"commonwealth-F2006B02543-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AT/14 - Never Exceed Airspeed Limit","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)  \nAirtractor AT-300, 400 and 500 Series Aeroplanes\n\nAD/AT/14 Never Exceed Airspeed Limit 8/92\n\nApplicability: AT-302 all serial numbers, AT-400 all serial numbers, AT-400A all serial numbers, AT-402 all serial numbers up to and including 402-0784, AT-402A all serial numbers up to and including 402A-0782, AT-502 all serial numbers up to and including 502- 0118 and AT-503A all serial numbers up to and including 503A-0067.\n\nRequirement: Re-mark the Vne (Never Exceed Speed) \\`red line’ radial marking on Airspeed Indicators as follows:\n\n    119 kts IAS for AT-302, AT-400, AT-400A and AT-402 and AT-402A aircraft.\n\n    b. 133 kts IAS for AT-502 and AT-503A aircraft.\n\nMarkings above these speeds should be removed from the indicator.\n\nNote 1: Snow Engineering Company Service Letter 91 refers.\n\nNote 2: Appropriate Flight Manual amendments reflecting the revised Vne will be issued in due course.\n\nCompliance: Before the issue of the next Maintenance Release or 31 October 1992, whichever occurs first.\n\nBackground: This Directive is issued following a re-evaluation of the propeller certification data by Hartzell. Compliance with this Directive provides the pilot of the aircraft with an indication of the aircraft’s upper airspeed limit, which if exceeded, will cause the propeller blades to be subjected to unacceptable stress levels.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"The Directive amends the indicated operational limit by prescribing new Vne markings and removing higher markings on the airspeed indicator (Requirement). That changes what speed pilots will regard as the aircraft’s upper limit and requires corresponding flight manual amendments and instrument re-marking; the burden falls on operators/maintenance providers to implement before the specified compliance trigger (Compliance)."},"complexity_factors":["Narrow and explicit applicability by model and serial numbers (Requirement), which simplifies target population but requires serial-number checks.","Single, mechanical action mandated (re-marking and removal of higher markings) — low technical complexity.","Two distinct Vne values across subgroups (119 kts and 133 kts) increases clerical care to apply correct marking to each aeroplane.","Fixed compliance trigger: before next Maintenance Release or 31 Oct 1992 (Compliance) creates a conditional deadline to track.","References to Snow Engineering Service Letter 91 and pending Flight Manual amendments introduce coordination with service and documentation updates.","Safety-critical consequence (propeller overstress if exceeded) raises enforcement urgency though not procedural complexity."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of the listed Airtractor AT-300, 400 and 500 series aeroplanes to re-mark the Vne (never exceed) red‑line on the airspeed indicator to 119 kts IAS for most AT-300/400/402 types and 133 kts IAS for specified AT-502/503A types, and to remove any higher markings. It follows a Hartzell propeller re‑evaluation and aims to show the propeller’s upper safe speed. Compliance is due before the next Maintenance Release or by 31 October 1992; flight manual amendments will follow."},"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 Airworthiness Directive maintains its original narrow scope — a specific safety correction for specific aircraft models based on new propeller certification data. It has not expanded beyond its original purpose of addressing the Vne speed limit issue."},"complexity_factors":["Single, specific technical requirement (re-marking an instrument)","Limited applicability (7 specific aircraft models with serial number ranges)","No nested exceptions or conditional logic","Only 2 defined speed values (119 kts and 133 kts)","Straightforward compliance deadline","No cross-references to other legislation beyond a service letter note"],"plain_english_summary":"This Airworthiness Directive lowers the maximum safe airspeed (the red‑line) for certain older Air Tractor AT‑300/400/500 series crop‑dusters and requires owners to revise airspeed indicators and remove any markings above the new limit.  \n\nIssued after Hartzell found the original limits can overstress propeller blades, it affects listed older serial numbers and must be complied with by the next maintenance or by 31 Oct 1992 to prevent propeller failure and crashes."}},"importantCases":[],"_links":{"self":"/api/acts/ad-at-14-never-exceed-airspeed-limit","history":"/api/acts/ad-at-14-never-exceed-airspeed-limit/history","analysis":"/api/acts/ad-at-14-never-exceed-airspeed-limit/analysis","conflicts":"/api/acts/ad-at-14-never-exceed-airspeed-limit/conflicts","importantCases":"/api/acts/ad-at-14-never-exceed-airspeed-limit/important-cases","documents":"/api/acts/ad-at-14-never-exceed-airspeed-limit/documents"}}