{"id":"F2006B07486","name":"AD/TSA-600/21 - Engine Nacelle Drain Tubes - Modification","slug":"ad-tsa-600-21-engine-nacelle-drain-tubes-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49927,"registerId":"commonwealth-F2006B07486-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TSA-600/21 - Engine Nacelle Drain Tubes - 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)  Aerostar (Piper/Ted Smith) 600 and 700 Series Aeroplanes\n\n \n\nAD/TSA-600/21 Engine Nacelle Drain Tubes - Modification 6/79\n\nApplicability: All models with Airframe Sequence Numbers below 0660. Document:  1. Piper Aerostar SB No. SB600-80, Part II; or\n\n2. FAA AD 79-08-05, Amendment 39-3449.\n\n \n\nCompliance: Within 100 hours time in service after 30 June 1979.\n\n \n\nBackground: In the event of a wing tank fuel leak there is a possibility that fuel will enter and accumulate in the lower nacelle compartment aft of the firewall to be ignited during engine startup.\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\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The supplied text sets a clear, limited scope: Aerostar (Piper/Ted Smith) 600 and 700 series aeroplanes with Airframe Sequence Numbers below 0660 must be modified according to the specified Piper service bulletin or FAA AD within 100 hours TIS after 30 June 1979. The document does not indicate any expansion or narrowing of that scope beyond these stated criteria."},"complexity_factors":["Narrow technical scope limited to Aerostar 600/700 series with Airframe Sequence Numbers below 0660 (Applicability).","Mandates a single, time-limited compliance action (100 hours TIS after 30 June 1979) rather than ongoing monitoring (Compliance).","Relies on external technical documents (Piper SB or FAA AD) for the procedural detail, requiring access to and interpretation of those documents (Document).","Requires tracking of hours-in-service to meet the deadline, adding modest administrative recordkeeping.","Potential operational scheduling and parts/skill availability constraints for a small subset of aircraft owners."],"plain_english_summary":"This AD requires owners/operators of Aerostar 600/700 series aircraft with airframe sequence numbers below 0660 to modify the engine nacelle drain tubes per Piper SB600-80 Part II or FAA AD 79-08-05. Work must be completed within 100 hours TIS after 30 June 1979. The change reduces the risk that wing-tank fuel will collect in the lower nacelle aft of the firewall and ignite on engine start. Costs and downtime fall to owners/operators."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on engine nacelle drain tube modifications for a particular aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 200 words)","Only 2 defined applicability criteria (aircraft model and serial number range)","Single compliance requirement with clear deadline","No cross-references to other legislation beyond two technical documents","No conditional logic, exceptions, or nested provisions","Straightforward cause-and-effect safety rationale"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nRequires owners and operators of specific **Aerostar (Piper/Ted Smith) 600 and 700 series aeroplanes** to modify the engine nacelle drain tubes. A \"nacelle\" is the housing that surrounds an aircraft engine on the wing.\n\n**Who it affects:**\nAnyone who owns or operates Aerostar 600 or 700 series aircraft with **airframe serial numbers below 0660**.\n\n**Why it matters:**\nThere's a serious fire risk. If fuel leaks from a wing tank, it can pool in the lower engine compartment behind the firewall. When the engine starts, this accumulated fuel could ignite. The modification prevents this dangerous fuel accumulation.\n\n**What must be done:**\n- Follow the instructions in **Piper Aerostar Service Bulletin SB600-80, Part II**, OR the equivalent **US Federal Aviation Administration AD 79-08-05**\n- Complete the work **within 100 hours of flight time after 30 June 1979**\n\n**Bottom line:** This is a critical safety fix to prevent engine fires caused by fuel leaks in older Aerostar aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tsa-600-21-engine-nacelle-drain-tubes-modification","history":"/api/acts/ad-tsa-600-21-engine-nacelle-drain-tubes-modification/history","analysis":"/api/acts/ad-tsa-600-21-engine-nacelle-drain-tubes-modification/analysis","conflicts":"/api/acts/ad-tsa-600-21-engine-nacelle-drain-tubes-modification/conflicts","importantCases":"/api/acts/ad-tsa-600-21-engine-nacelle-drain-tubes-modification/important-cases","documents":"/api/acts/ad-tsa-600-21-engine-nacelle-drain-tubes-modification/documents"}}