{"id":"F2006B10268","name":"AD/GENERAL/22 - Engine Oil Tank - Modification","slug":"ad-general-22-engine-oil-tank-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55947,"registerId":"commonwealth-F2006B10268-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GENERAL/22 - Engine Oil Tank - Modification","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)  \nAircraft \\- General\n\nAD/GENERAL/22 Engine Oil Tank \\- Modification NK\n\nApplicability: All aeroplanes fitted with hydraulically operated feathering propellers which draw their feathering oil supply from the engine oil tank.\n\nRequirement: 1. Modify engine oil tanks by reworking the engine oil supply standpipe in such a manner that, in the event of exhaustion of the engine oil supply, sufficient oil will be retained in the tank to enable the propeller to be feathered. This reserve supply shall be available only to the feathering pump; or\n\nNote: In some installations incorporating a hopper in the oil tank, there is a possibility of an increase in the height of the standpipe causing a restriction of the flow of oil from tank to hopper leading to oil starvation under cold starting conditions and overheating of oil under high power. In such cases, it will be necessary also to modify the neck of the hopper to ensure that restriction of oil flow cannot take place.\n\n2. ANO 105.1.0.1.49; or\n\n3. AD/DC3/22.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1207},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope addressing the specific safety risk of propeller unfeatherability due to oil tank design. No expansion beyond the original technical mandate is evident."},"complexity_factors":["Technical aviation terminology requiring engineering knowledge (feathering propellers, standpipes, hoppers, ANO references)","Cross-references to other regulatory documents (ANO 105.1.0.1.49 and AD/DC3/22)","Conditional exceptions requiring case-by-case mechanical assessment (hopper modification note)"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of aeroplanes with hydraulically operated feathering propellers (that draw oil from the main engine oil tank) to modify the tank’s oil supply standpipe so a reserve of oil is trapped and available only to the feathering pump. If a tank has an internal hopper, its neck may also need modification to avoid hopper starvation or overheating. The change preserves the ability to feather a failed engine when the main oil supply is lost."}},"importantCases":[],"_links":{"self":"/api/acts/ad-general-22-engine-oil-tank-modification","history":"/api/acts/ad-general-22-engine-oil-tank-modification/history","analysis":"/api/acts/ad-general-22-engine-oil-tank-modification/analysis","conflicts":"/api/acts/ad-general-22-engine-oil-tank-modification/conflicts","importantCases":"/api/acts/ad-general-22-engine-oil-tank-modification/important-cases","documents":"/api/acts/ad-general-22-engine-oil-tank-modification/documents"}}