{"id":"F2016L01941","name":"AD/GAS/1 Amdt 12 - Inspection, Test and Retirement","slug":"ad-gas-1-amdt-12-inspection-test-and-retirement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":95598,"registerId":"commonwealth-F2016L01941-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Compressed Gas Cylinders","sectionType":"division","heading":"Compressed Gas Cylinders","content":"### Compressed Gas Cylinders\n\n| AD/GAS/1 Amdt 12 | Inspection, Test and Retirement | 26/2016 |\n| ---------------- | ------------------------------- | ------- |\n\n| Applicability: | Aircraft to which Part 42 of CASR 1998 applies which carry rechargeable compressed gas cylinders that are not fire extinguishers.This AD is not applicable if the aircraft’s Approved Maintenance Program includes procedures for inspection, test and retirement of compressed gas cylinders, valves and regulators. |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. The compressed gas cylinders shall be emptied. Except as varied below, the gas cylinders must be hydrostatically tested and have their markings updated to conform with the applicable manufacturer's, Australian Standard (AS) or United States Department of Transportation (DOT) specification, as set out below:(a) Cylinders with a working pressure of less than 1MPa are not required to be subject to hydrostatic testing.(b) Cylinders manufactured in the USA which have an outside diameter of less than 51 mm and length less than 610 mm are not required to be subject to hydrostatic testing.(c) The retest of aircraft compressed gas cylinders must include a visual internal and external inspection together with a test by interior hydrostatic pressure in a water jacket or other apparatus of suitable form for the determination of the expansion of the cylinder. Permanent volumetric expansion must not exceed 10% of total volumetric expansion at test pressure or a permanent increase in volume of more than 1/5000 of its original volume.(d) Where a cylinder specification or applicable CGA Publication does not adequately define damage limits, 50% of the damage tolerances stated in AS2030 shall be applied.(e) Cylinders manufactured in the USA marked 3HT must be inspected and tested in accordance with the USA Compressed Gas Association Publication C-8, as in force from time to time (Standards for Visual Inspection of Compressed Gas Cylinders (1972), 49 CFR §180.209 and 180.213(c) (2) refer). |\n| | (f) A hydrostatic proof test can be performed as an alternative to a hydrostatic stretch test, but only where permitted by a particular cylinder specification.2. Inspect and test the valve and/or the regulator in accordance with the manufacturer’s specifications. If no manufacturer’s specification are available then the valve must be inspected in accordance with paragraph 10.2.2 of AS2337.1-2004, as in force from time to time.3. Retire cylinder from service.4. Cylinders which do not comply with their scheduled inspection limits or test requirements must be rendered unfit for further use in accordance with AS2030, as in force from time to time. |\n| Compliance: | 1. Unless it can be positively established and certified when the last hydrostatic test was carried out and is again due, emptying and testing should be carried out within 1 year after 31 August 1986 and thereafter at intervals not exceeding 5 years except for:(a) 3HT cylinders, which must be tested at intervals not exceeding 3 years, and(b) DOT-E type cylinders, which must be tested in accordance with the DOT Special Permit, as in force from time to time, or 3 years.2. In accordance with the manufacturer’s requirements or at the same time as the cylinder inspection whichever is the lesser.3. In accordance with whichever of the following occurs first:(a) the manufacturer's specification,(b) for 3HT cylinders:(i) 4 380 pressurisations (cycles), or(ii) 24 years from date of manufacture; or(c) HOLASW 1** cylinders:(i) 5 000 pressurisations (cycles), or(ii) 25 years from date of manufacture.(d) for fibrewrapped cylinders:(i) the limit specified in the applicable DOT-Exemption, as in force from time to time, or(ii) 15 years from the date of manufacture.4. Immediately. |\n| | Note 1: Not all specifications include a retirement requirement.Note 2: From the effective date of this amendment, and where the number of pressurisation cycles prior to this amendment have not been recorded, or cannot be substantiated, and where a cylinder is, or has been:(a) installed only for emergency purposes, it is to be assumed to have consumed 1 cycle every 2 days since date of manufacture; or(b) installed or used for the normal provision of supplementary oxygen above an altitude, or cabin altitude of 10 000 feet, it is to be assumed to have consumed 1 cycle each day since the date of manufacture.Note 3: A reference in this AD to a document being in force from time to time, is a reference only to the latest / current version of the document. |\n| | This AD commences on 6 January 2017. |\n| Background: | Amendment 7 recognised the cycle life limit of USA 3HT, and UK HOLASW cylinders. It has been established for emergency oxygen systems that the normal frequency of topping up, and only cycling pressure from despatch limits to maximum, will allow this class of cylinder where applicable, to retain its full remaining calendar life. However, where no records exist, cylinders for routine high altitude use must be assumed to have been fully cycled from empty to full, and on a regular basis.Amendment 8 aligned the Directive with the change in the Australia Standard AS 2337.1 which requires the valve to be inspected along with the gas cylinder and regulator.Amendment 9 was issued because US DOT Exemption E 8162 had been superseded by US DOT Special Permit SP 8162 dated 11 May 2007. US DOT-SP 8162 changes the hydrostatic test interval of lightweight composite oxygen cylinders from 3 years to 5 years for cylinders that have been tested after 1 July 2006.Amendment 10 was issued to limit the applicability of the AD to CASR Part 42 aircraft only. This AD will be repealed after the requirements are incorporated into a future amendment of the Part 42 Manual of Standards.Amendment 11 was issued to clarify the applicability under CASR Subpart42.J. |\n\n| | Amendment 12 is issued to make minor editorial changes. |\n| --- | ------------------------------------------------------- |\n\n![](image.001.png)\n\nBen Wilson \nDelegate of the Civil Aviation Safety Authority\n\n12 December 2016","sortOrder":0},{"sectionNumber":"AD/GAS/1 Amdt 12","sectionType":"part","heading":"AD/GAS/1 Amdt 12","content":"## AD/GAS/1 Amdt 12","sortOrder":1},{"sectionNumber":"Inspection, Test and Retirement","sectionType":"part","heading":"Inspection, Test and Retirement","content":"## Inspection, Test and Retirement","sortOrder":2},{"sectionNumber":"26/2016","sectionType":"part","heading":"26/2016","content":"## 26/2016","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"The Directive's scope has been narrowed and clarified over successive amendments: Amendment 10 limited applicability to aircraft subject to CASR Part 42; Amendment 11 clarified applicability under Subpart 42.J; Amendment 12 made editorial changes. The AD therefore now applies only to Part 42 aircraft and excludes aircraft whose Approved Maintenance Program already contains equivalent procedures (Applicability; Background)."},"complexity_factors":["Multiple cylinder-type specific rules and exceptions (e.g. working pressure <1 MPa, USA cylinders <51 mm OD and <610 mm length, 3HT, DOT‑E/DOT‑Exemption, HOLASW, fibrewrapped) (Requirement 1(a),(b),(e); Compliance 1(a),(b),(c),(d)).","Cross-references to numerous external standards and documents that are cited 'as in force from time to time' (manufacturer specs; AS2030; AS2337.1-2004; CGA C-8; DOT special permits) creating dynamic normative dependencies (Requirement 1(c),(d),(e); Requirement 2; Notes).","Different testing methods and limits allowed (hydrostatic stretch test, hydrostatic proof test where permitted, interior inspection, permanent expansion limits) with technical acceptance criteria (Requirement 1(c),(f)).","Multiple, non-uniform compliance intervals and retirement triggers (standard 5‑year, 3HT three‑year/3HT cycle or 24-year limits, DOT exceptions, HOLASW cycles/25 years, fibrewrapped limits/15 years) increasing scheduling complexity (Compliance 1,3).","Record‑keeping and assumed cycle rules where historical pressurisation data are missing (assumed cycles for emergency vs routine use) creating retrospective compliance assumptions (Notes 2).","Applicability limited to CASR Part 42 aircraft and exclusion where an Approved Maintenance Program already covers these tasks — conditional scope adds a regulatory-filtering step for operators (Applicability; Background/Amendment 10 & 11).","Retirement and unfitness determinations defer to AS2030 or referenced standards, placing technical judgement and compliance burden on maintainers to apply external damage tolerances (Requirement 4; Requirement 1(d))."],"plain_english_summary":"This Airworthiness Directive requires operators of aircraft governed by CASR Part 42 that carry rechargeable compressed gas cylinders (other than fire extinguishers) to empty, inspect, hydrostatically test or retire those cylinders, and to inspect/test valves and regulators in line with manufacturer, Australian Standard, DOT or CGA specifications (Requirement; Compliance). Owners/operators pay for testing and retirement, must follow specified intervals or assumed cycle counts where records are missing, and maintenance organisations decide methods within the referenced standards (Requirement; Compliance; Notes)."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":true,"description":"Originally a straightforward safety directive for compressed gas cylinder testing, the legislation has expanded significantly through 12 amendments. Amendment 7 added cycle-life limits for specific cylinder types; Amendment 8 incorporated valve inspection requirements; Amendment 9 tracked changes to US DOT permits; Amendment 10 narrowed applicability to Part 42 aircraft only (anticipating future incorporation into the Part 42 Manual of Standards); Amendment 11 addressed Subpart 42.J applicability; and Amendment 12 made 'minor editorial changes.' The directive has evolved from simple hydrostatic testing intervals into a comprehensive regime covering cylinder specifications, valve/regulator testing, retirement criteria based on cycles and calendar age, presumptive calculations for missing records, and complex interactions with both Australian and US standards. The Background note explicitly states this AD will be repealed once requirements are incorporated into the Part 42 Manual of Standards, indicating the current form is transitional scope creep pending consolidation."},"complexity_factors":["Multiple nested exception categories: working pressure thresholds (<1MPa), dimensional exemptions (US-made cylinders <51mm diameter and <610mm length), and specification-specific rules (3HT, DOT-E, HOLASW 1**, fibrewrapped)","Cross-references to multiple external standards: Australian Standards (AS2030, AS2337.1-2004), US Department of Transportation regulations (49 CFR §180.209, 180.213(c)(2)), US Compressed Gas Association Publication C-8, and manufacturer specifications — all referenced 'as in force from time to time'","Dual compliance pathways: manufacturer's specifications vs. generic standards, with hierarchical rules for which takes precedence","Complex retirement logic with multiple triggering conditions: pressurisation cycle counts (ranging from 4,380 to 5,000 cycles), calendar age limits (15-25 years depending on cylinder type), and 'whichever occurs first' clauses","Presumptive calculation rules for missing records: different daily/2-day cycle assumptions based on installation purpose (emergency vs. routine high-altitude use)","Conditional applicability: applies only to Part 42 CASR aircraft, with exemption for aircraft with existing Approved Maintenance Program procedures","Historical amendment tracking: references to Amendments 7-11 explaining evolution of requirements, indicating layered regulatory history"],"plain_english_summary":"This CASA Airworthiness Directive mandates regular inspection, hydrostatic testing, and end-of-life retirement for aircraft compressed gas cylinders (e.g., emergency oxygen systems) to prevent catastrophic failure from fatigue or corrosion. It applies to aircraft maintained under CASR Part 42 unless equivalent procedures are in an Approved Maintenance Program. The AD also sets assumptions for unknown usage histories and requires failed cylinders be permanently taken out of service."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gas-1-amdt-12-inspection-test-and-retirement","history":"/api/acts/ad-gas-1-amdt-12-inspection-test-and-retirement/history","analysis":"/api/acts/ad-gas-1-amdt-12-inspection-test-and-retirement/analysis","conflicts":"/api/acts/ad-gas-1-amdt-12-inspection-test-and-retirement/conflicts","importantCases":"/api/acts/ad-gas-1-amdt-12-inspection-test-and-retirement/important-cases","documents":"/api/acts/ad-gas-1-amdt-12-inspection-test-and-retirement/documents"}}