{"id":"F2006B03010","name":"AD/B747/109 - Passenger Oxygen System Continuous Flow Control Unit","slug":"ad-b747-109-passenger-oxygen-system-continuous-flow-control-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42369,"registerId":"commonwealth-F2006B03010-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/109 - Passenger Oxygen System Continuous Flow Control Unit","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)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/109 Passenger Oxygen System Continuous\n\nFlow Control Unit\n\n  \n5/92\n\nApplicability: Boeing 747 series aircraft listed in Boeing Service Bulletin 747-35-2074 Revision 1.\n\nRequirement: Action in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-35-2074 Revision 1.\n\nNote: FAA AD 92-04-03 Amdt 39-8172 refers.\n\nCompliance: Within 4000 hours time in service after 30 April 1992.\n\nBackground: The FAA has received reports of flow control units not activating at the proper altitude during a maintenance check of the system; the malfunction being caused by manufacturing defects in the flow control units. The defective units, if not replaced, can prevent the automatic deployment of oxygen to the passenger oxygen system in the event of loss of cabin pressure.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a single, specific purpose. It has not expanded beyond its original intent of addressing a known manufacturing defect in oxygen system components."},"complexity_factors":["Very short document — approximately 150 words","Only 1 defined applicability criterion (Boeing Service Bulletin reference)","Single, unambiguous compliance action with clear deadline","No nested conditions, exceptions, or cross-references to other legislation beyond the FAA AD note","No interpretation section or defined terms"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific Boeing 747 aircraft.\n\n**What it does:**\nOrders airlines and aircraft operators to inspect and replace faulty **passenger oxygen flow control units** — the devices that automatically release oxygen masks to passengers if the cabin suddenly loses pressure (such as during an emergency descent).\n\n**Why it matters:**\nManufacturing defects in these units were causing them to fail during maintenance tests. If not fixed, passengers wouldn't get emergency oxygen during a decompression event — a potentially fatal safety risk.\n\n**Who must comply:**\nOperators of Boeing 747 series aircraft covered by Boeing Service Bulletin 747-35-2074 Revision 1.\n\n**What must be done:**\nFollow the repair instructions in that Boeing Service Bulletin exactly.\n\n**Deadline:**\nWithin 4,000 flight hours after 30 April 1992.\n\n**Key point:** This directive references a US Federal Aviation Administration (FAA) safety order (AD 92-04-03), showing Australia was adopting an American safety finding for local use."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument, as published, imposes a specific maintenance requirement on Boeing 747 aeroplanes identified in Boeing Service Bulletin 747-35-2074 Revision 1 and sets a clear compliance window. The text does not state that it expands or narrows a previously stated scope; it simply prescribes action for the aircraft listed in the referenced Service Bulletin within the stated timeframe (Applicability; Requirement; Compliance)."},"complexity_factors":["Direct reliance on an external Boeing Service Bulletin for detailed technical instructions (Requirement).","Applicability limited to aircraft listed in that Service Bulletin—requires cross-referencing to identify affected aeroplanes (Applicability).","Compliance measured in flight hours with a fixed deadline relative to a calendar date (Compliance).","Safety-critical subject matter (passenger oxygen system) increases operational importance despite straightforward directive text (Background).","Reference to related FAA AD for context but not for procedural content (Note)."],"plain_english_summary":"This Airworthiness Directive from the Civil Aviation Safety Authority requires operators of the Boeing 747 aeroplanes listed in Boeing Service Bulletin 747-35-2074 Revision 1 to carry out the bulletin’s maintenance on passenger oxygen system flow control units within 4,000 flight hours after 30 April 1992. \n\nIt addresses manufacturing defects that can prevent automatic oxygen deployment; compliance is the operators’ responsibility and must be scheduled and performed by them or their maintenance providers following Boeing’s instructions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-109-passenger-oxygen-system-continuous-flow-control-unit","history":"/api/acts/ad-b747-109-passenger-oxygen-system-continuous-flow-control-unit/history","analysis":"/api/acts/ad-b747-109-passenger-oxygen-system-continuous-flow-control-unit/analysis","conflicts":"/api/acts/ad-b747-109-passenger-oxygen-system-continuous-flow-control-unit/conflicts","importantCases":"/api/acts/ad-b747-109-passenger-oxygen-system-continuous-flow-control-unit/important-cases","documents":"/api/acts/ad-b747-109-passenger-oxygen-system-continuous-flow-control-unit/documents"}}