{"id":"F2006B05490","name":"AD/PA-23/63 - Heater Fuel Valve - Inspection","slug":"ad-pa-23-63-heater-fuel-valve-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46318,"registerId":"commonwealth-F2006B05490-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-23/63 - Heater Fuel Valve - Inspection","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)  Piper PA-23 (Apache and Aztec) Series Aeroplanes\n\n \n\nAD/PA-23/63 Heater Fuel Valve - Inspection 7/74\n\nApplicability: Models PA23-150 and PA23-160 with S/Nos. 23-1 to 23-2046, Models PA23-235 and PA23-250 with S/Nos. 27-1 to 27-3836, 27-3838 to 27-3943.\n\n \n\nDocument: Piper SB No. 401.\n\n \n\nCompliance: Within 100 hours time in service after 31 July 1974.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-limited safety directive focused on a specific mechanical component. It has not expanded beyond its original purpose of ensuring heater fuel valve integrity in affected Piper aircraft."},"complexity_factors":["Very short document (under 150 words)","Only 4 defined applicability criteria (model numbers and serial number ranges)","Single, unambiguous compliance requirement (one inspection within 100 hours)","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","No conditional logic, exceptions, or nested provisions","Clear, technical but straightforward language typical of aviation maintenance directives"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a \"recall notice\" for aircraft, but legally binding.\n\n**What it requires:** Owners and operators of specific **Piper PA-23 Apache and Aztec aeroplanes** must inspect the **heater fuel valve** within 100 hours of flying time after 31 July 1974.\n\n**Who it affects:**\n- **Specific aircraft models:** PA23-150, PA23-160, PA23-235, and PA23-250\n- **Specific serial numbers:** Only aircraft built within certain production ranges (roughly early production through the mid-1960s)\n\n**Why it matters:** The heater fuel valve controls fuel flow to the aircraft's cabin heater. A faulty valve could leak fuel or malfunction, creating fire risk or carbon monoxide hazards in the cabin. This AD mandates a one-time inspection to catch potential defects before they cause accidents.\n\n**Compliance deadline:** The inspection had to be completed within 100 \"hours time in service\" (flying hours, not calendar time) starting from 31 July 1974.\n\n**Source:** The directive references **Piper Service Bulletin No. 401** — the manufacturer's official technical instruction for how to perform the inspection."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Based solely on the text provided, the AD sets a specific, limited scope (listed PA-23 models and serial numbers) and a fixed compliance window tied to a past date. The instrument does not indicate any change from an earlier scope within the text supplied; therefore there is no evidence in this document that the scope has changed from the original intent. (See: \"Applicability\" and \"Compliance\".)"},"complexity_factors":["Narrow, serial-numbered applicability makes scope easy to determine from the text (\"Applicability\").","Short, explicit compliance window tied to a calendar reference and flight hours (\"Within 100 hours time in service after 31 July 1974\") reduces procedural complexity (\"Compliance\").","Procedural details are delegated to an external document (Piper SB No. 401), creating a dependence on that bulletin for full technical compliance (\"Document\").","The AD itself contains minimal procedural or enforcement detail, so implementers must consult the SB for inspection steps, which adds a retrieval/interpretation step.","Historical dating (1974) could create practical issues for locating the correct service bulletin or determining the current applicability of the SN ranges over time."],"plain_english_summary":"Mandates inspection of the heater fuel valve on specified Piper PA‑23 aircraft (listed serial ranges) per Piper Service Bulletin No. 401, to be completed within 100 hours TIS after 31 July 1974. Affects owners/operators who must arrange and pay for the inspection and any follow‑up; procedural detail is contained in the SB."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-23-63-heater-fuel-valve-inspection","history":"/api/acts/ad-pa-23-63-heater-fuel-valve-inspection/history","analysis":"/api/acts/ad-pa-23-63-heater-fuel-valve-inspection/analysis","conflicts":"/api/acts/ad-pa-23-63-heater-fuel-valve-inspection/conflicts","importantCases":"/api/acts/ad-pa-23-63-heater-fuel-valve-inspection/important-cases","documents":"/api/acts/ad-pa-23-63-heater-fuel-valve-inspection/documents"}}