{"id":"F2006B07589","name":"AD/VIPER/7 - Oil Tank Drain Valve","slug":"ad-viper-7-oil-tank-drain-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50234,"registerId":"commonwealth-F2006B07589-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/VIPER/7 - Oil Tank Drain Valve","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nRolls Royce Turbine Engines \\- Viper Series\n\nAD/VIPER/7 Oil Tank Drain Valve 7/90\n\nApplicability: Viper Mk 601-22 engines.\n\nRequirement: Inspect oil tank drain valve assembly for leakage in accordance with Rolls Royce Viper Mk 601-22 Service Bulletin No 79-A4.\n\nNote: CAA (UK ) Airworthiness Directive 015-04-90 refers.\n\nCompliance: Effective 12 July 1990:\n\n    (1) Engines in service \\- Prior to 20 July 1990.\n\n    (2) Prior to installation in an aircraft.\n\nBackground: Failure to detect oil leakage at the oil tank drain valve may result in total loss of oil pressure. Investigation of a total loss of oil pressure on a test flight following engine installation, revealed that the oil tank drain valve cap was not in position and the drain valve was stuck open allowing a rapid loss of oil tank contents.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive addressing a specific mechanical failure mode. It has not expanded beyond its original purpose of preventing oil loss in Viper Mk 601-22 engines."},"complexity_factors":["Single, specific mechanical component addressed (oil tank drain valve)","Only one engine model affected (Viper Mk 601-22)","Single compliance action required (visual inspection for leakage)","Clear, fixed deadline (20 July 1990)","No nested exceptions, conditional logic, or cross-references to other legislation","Refers to only one external technical document (Service Bulletin No 79-A4)","Total length: approximately 150 words"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft engines.\n\n**What it does:** It requires owners and operators of specific Rolls Royce Viper engines (the Mk 601-22 model) to inspect the oil tank drain valve for leaks. The inspection must follow a specific technical procedure laid out in a Rolls Royce Service Bulletin (No 79-A4).\n\n**Who it affects:** Anyone operating or maintaining aircraft with Viper Mk 601-22 engines — typically these are used in older military trainer or light jet aircraft in Australia.\n\n**Why it matters:** A faulty drain valve can cause catastrophic engine failure. The background explains that if the valve cap isn't properly seated and the valve sticks open, the engine can lose all its oil in minutes. This actually happened during a test flight, prompting this safety order.\n\n**When compliance is required:**\n- For engines already in use: before 20 July 1990\n- For engines being installed: before they go into an aircraft\n\n**Key point:** This isn't optional. Airworthiness Directives are legally binding safety requirements. Ignoring them means the aircraft cannot legally fly."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument applies only to Viper Mk 601-22 engines and prescribes a single inspection action per the Rolls Royce service bulletin. The text contains no indication that the directive changes or expands scope beyond this targeted inspection requirement."},"complexity_factors":["Narrow technical applicability limited to Rolls Royce Viper Mk 601-22 engines (Applicability)","Single, specific mandatory action (inspect oil tank drain valve assembly) referenced to an external service bulletin (Requirement)","Short, fixed compliance deadlines for in-service engines and pre-installation requirement (Compliance)","Dependence on an external manufacturer service bulletin for technical detail creates an additional step to implement (Requirement)","Operational coordination required between operators and maintenance providers but no multi-stage regulatory process described (Compliance)"],"plain_english_summary":"This directive mandates inspection of the oil‑tank drain valve assembly on Rolls‑Royce Viper Mk 601‑22 engines per Rolls‑Royce Service Bulletin No. 79‑A4. It affects owners, operators, maintenance providers, and anyone installing these engines.\n\nEffective 12 July 1990, in‑service engines had to be inspected by 20 July 1990, and any engine must be inspected before installation. The check aims to detect oil‑leakage risks that could cause rapid oil loss and engine failure; owners/operators bear inspection and repair costs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-viper-7-oil-tank-drain-valve","history":"/api/acts/ad-viper-7-oil-tank-drain-valve/history","analysis":"/api/acts/ad-viper-7-oil-tank-drain-valve/analysis","conflicts":"/api/acts/ad-viper-7-oil-tank-drain-valve/conflicts","importantCases":"/api/acts/ad-viper-7-oil-tank-drain-valve/important-cases","documents":"/api/acts/ad-viper-7-oil-tank-drain-valve/documents"}}