{"id":"F2006B02402","name":"AD/AMD 50/6 - Flight Control Area at Frame 25","slug":"ad-amd-50-6-flight-control-area-at-frame-25","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41645,"registerId":"commonwealth-F2006B02402-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AMD 50/6 - Flight Control Area at Frame 25","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)  \nAMD Falcon 50 and 900 Series Aeroplanes\n\nAD/AMD 50/6 Flight Control Area at Frame 25 9/93\n\nApplicability: Model F900 with a FJC-type interior.\n\nModel F900 with a DASSAULT AVIATION-type interior.\n\nRequirement: Action in accordance with the technical requirements of DGAC AD 92-067-010(B).\n\nNote: Dassault Aviation SB F900-113 and SB F900-115 refer.\n\nCompliance: As specified in the Requirement Document with a revised effective date of 19 August 1993.\n\nBackground: Water accumulation in the underfloor area at frame 25 would create the possibility that the engine and flight controls could jam in the event of extreme low temperature conditions. This Directive requires certain actions and checks of the water system, and a modification which is designed to improve underfloor heating.\n\ns","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive’s scope is limited to Falcon 900 aeroplanes with FJC-type or Dassault Aviation-type interiors and requires actions specified in the referenced DGAC AD and Dassault service bulletins. The text contains no indication the scope has changed from its stated purpose of addressing water accumulation and freezing risk at frame 25; compliance is required as specified with a revised effective date (19 August 1993). (Applicability) (Background) (Compliance)"},"complexity_factors":["Directive references external technical documents (DGAC AD 92-067-010(B)) for the substantive steps, increasing practical complexity for implementers.","Cross-reference to manufacturer service bulletins (Dassault SB F900-113 and SB F900-115) means required actions are specified outside the directive text.","Applicability is narrowly drawn (specific model and interior types), requiring accurate fleet identification by operators.","Directive specifies actions and a modification but does not list detailed procedures, times, or costs within the text itself.","Compliance depends on a revised effective date, which implementers must observe to schedule work and maintain regulatory compliance."],"plain_english_summary":"What this directive does (mechanical change)\n\n- It requires operators of certain Dassault Falcon 900 series aeroplanes to carry out specific inspections, checks and a physical modification to the aircraft's underfloor heating/water system. The required actions must be performed in accordance with the technical instructions given in DGAC AD 92-067-010(B) (Requirement). (Applicability) (Requirement)\n\nWho it affects\n\n- The directive applies to Falcon 900 (F900) aeroplanes that have either an FJC-type interior or a Dassault Aviation-type interior. Owners, operators and maintenance organisations responsible for those specific aeroplanes are obliged to follow the directive. (Applicability)\n\nWhy it matters (official rationale and mechanical effect)\n\n- The stated safety concern is that water can accumulate under the cabin floor at frame 25; if that water were to freeze under extreme low-temperature conditions it could allow engine and flight-control components to jam. The directive addresses this by requiring checks of the water system and a modification intended to improve underfloor heating, reducing the freezing risk. (Background)\n\nHow it works in practice (who decides, who pays, and what changes)\n\n- The Civil Aviation Safety Authority issues the directive as part of the Schedule of Airworthiness Directives. The directive mandates that the technical steps in the referenced DGAC airworthiness directive be followed; it also cross-references Dassault Service Bulletins F900-113 and F900-115. Compliance must be achieved as specified in the Requirement document, with an effective (revised) date of 19 August 1993. (Header; Requirement; Note; Compliance)\n\n- Practically, affected aircraft must undergo the specified inspections/checks and receive the modification to improve underfloor heating. Those actions will need to be carried out by the aircraft owner/operator or by authorised maintenance organisations working for them, in line with the DGAC technical instructions. (Applicability) (Requirement)\n\nImplementation costs, incentives and trade-offs (source-grounded)\n\n- Costs and burdens: The directive requires labour and parts to perform checks and to carry out the modification; those costs and the time the aircraft is out of service will fall on the parties who own or operate the affected aeroplanes (the directive makes the action mandatory for the listed models and interiors). The text does not specify who pays or the cost amounts—only that the actions must be performed per the referenced technical document. (Applicability) (Requirement)\n\n- Incentives and behaviour: Compliance is mandatory for the listed aeroplanes; the immediate incentive for operators is reduced risk of frozen water causing control or engine jamming. The directive ties behaviour to an external technical standard (DGAC AD 92-067-010(B)), so operators’ choices are constrained to the measures specified in that standard. (Requirement)\n\n- Trade-offs and implementation risk: The directive substitutes a required retrofit/modification and checks for the status quo. The text states the modification is \"designed to improve underfloor heating,\" but it does not quantify performance improvements, implementation timelines beyond the effective date, or any operational limitations while work is done; those details are left to the referenced technical documents. As a result, the practical risk of delayed compliance, grounding time, or variable modification effectiveness depends on the technical requirements in the DGAC AD and the Dassault Service Bulletins. (Background) (Requirement) (Note) (Compliance)\n\nRegulatory discretion and compliance burden\n\n- The directive delegates the technical specification of the required work to DGAC AD 92-067-010(B) and to Dassault Service Bulletins F900-113 and F900-115 (Note). That means the CASA-issued directive prescribes compliance but relies on externally authored technical instructions for the detail; implementers must follow those documents. (Requirement) (Note)\n\nConcentrated benefits and diffuse costs (source-grounded observation)\n\n- The direct, concentrated benefit is to operators and passengers of the affected F900 aircraft: a reduced risk that underfloor water freezing will cause a jam of engines or flight controls. The costs (labour, parts, downtime) fall on the owners/operators of the affected aircraft, and the directive text does not specify compensation, exemptions, or alternatives. (Background) (Applicability) (Requirement)\n\nKey references in the text: Applicability; Requirement (DGAC AD 92-067-010(B)); Note (Dassault SB F900-113 and SB F900-115); Compliance (revised effective date 19 August 1993)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific airworthiness concern. It has not expanded beyond its original purpose of preventing flight control jamming due to water freezing at frame 25."},"complexity_factors":["Very short document (under 200 words)","Only 2 defined applicability categories (interior types)","Single technical requirement referencing an external French aviation authority document (DGAC AD 92-067-010(B))","No nested exceptions or conditional logic","Cross-reference to two Service Bulletins (SB F900-113 and SB F900-115) but these are informational only","Straightforward compliance deadline (single date)"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for specific Dassault Falcon business jets.\n\n**What it does:**\n- Requires owners and operators of certain Falcon 900 aircraft to take specific safety actions\n- Addresses a problem where water could collect beneath the floor near \"frame 25\" (a structural part of the fuselage)\n- In freezing conditions, this water could freeze and jam the engine and flight controls — a serious flight safety risk\n- Mandates inspections of the water system, plus installation of improved heating in the underfloor area\n\n**Who it affects:**\n- Operators of Falcon 900 jets with specific interior configurations (FJC-type or Dassault Aviation-type interiors)\n- Maintenance organisations servicing these aircraft\n\n**Why it matters:**\nFlight control jamming in flight could lead to loss of control. This directive prevents that by ensuring water doesn't freeze in critical areas. Compliance is mandatory — operators cannot legally fly these aircraft without completing these modifications and inspections."}},"importantCases":[],"_links":{"self":"/api/acts/ad-amd-50-6-flight-control-area-at-frame-25","history":"/api/acts/ad-amd-50-6-flight-control-area-at-frame-25/history","analysis":"/api/acts/ad-amd-50-6-flight-control-area-at-frame-25/analysis","conflicts":"/api/acts/ad-amd-50-6-flight-control-area-at-frame-25/conflicts","importantCases":"/api/acts/ad-amd-50-6-flight-control-area-at-frame-25/important-cases","documents":"/api/acts/ad-amd-50-6-flight-control-area-at-frame-25/documents"}}