{"id":"F2006B02397","name":"AD/AMD 50/30 Amdt 1 - Fire Extinguisher Selector Switches","slug":"ad-amd-50-30-amdt-1-fire-extinguisher-selector-switches","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41640,"registerId":"commonwealth-F2006B02397-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AMD 50/30 Amdt 1 - Fire Extinguisher Selector Switches","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AMD 50/30 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)\n\nAMD Falcon 50 and 900 Series Aeroplanes\n\nAD/AMD 50/30\n\nAmdt 1\n\n  \nFire Extinguisher Selector Switches 4/2003\n\nDM\n\nApplicability: All Mystère Falcon 900 series aeroplanes.\n\nRequirement: 1. Inspect the safety wires on the fire extinguisher selector switches to ensure all wires comply with NFL 23.321 or MS20995CY15\\* (or NASM20995CY15\\*). All wires not complying with these standards must be removed.\n\n\\* ‘CY’ Copper specification A-A-59551, type “S”, annealed, 0.015 inch.\n\n    2. Unless already accomplished in accordance with the original issue of this Directive, install fire extinguisher selector switch copper safety wires that either:\n\n    comply with NFL 23.321 or MS20995CY15 (or NASM20995CY15) standards, or\n    are copper having a maximum diameter of 0.4 millimetres and can withstand a rupture strength of less than 45 Newtons.\n\n    3. Incorporate Work Card MF900 26-203 temporary revision TC 115 into the Aircraft Maintenance Manual (AMM).\n\n    4. If copper safety wires were installed in accordance with Requirement 2.a. reinstall safety wires that comply with the Requirement 1 standards.\n\nNote: DGAC AD 2003-084(B) R1 refers.\n\nCompliance: For Requirement 1 \\- Remains unchanged as ‘Before further flight after the effective date of the original issue of this Directive’.\n\nFor Requirement 2 \\- Within eight days after the effective date of this Amendment.\n\nFor Requirement 3 \\- Remains unchanged as ‘Within eight days after the effective date of the original issue of this Directive’.\n\nFor Requirement 4 \\- Within three months after the effective date of this Amendment. This Amendment becomes effective on 12 March 2003.\n\nAMD Falcon 50 and 900 Series Aeroplanes\n\nAD/AMD 50/30 Amdt 1 (continued)\n\nBackground: The Direction Générale de l’Aviation Civile of France has advised that due to incorrect references on Work Card 26.203 incorrect safety (lock) wire may have been used to safety wire fire extinguisher selector switches following continuity checks between fire extinguishers and the fire control panel. The incorrect safety wire may prevent operation of the selector switches.\n\nThe original issue of this Directive required inspection and, if necessary, removal of the safety wires and their replacement with wires that meet certain standards.\n\nAdditionally, the AMM was required to be amended.\n\nThis Amendment introduces a revised specification for copper wires and provides an alternative method of compliance.\n\nThe original issue of the Airworthiness Directive became effective on 14 February 2003.\n\n![](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 5 March 2003\n\n![](image.003.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 12 March 2003.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The amendment does not expand the AD's overall purpose (ensuring safe operation of the fire extinguisher selector switches). It refines the technical specification for acceptable copper safety wire and adds a narrowly framed alternative method of compliance plus timing details. These are adjustments to means of compliance rather than a substantive broadening of scope or introduction of new regulatory objectives."},"complexity_factors":["Short document with 4 discrete mandatory Requirements (1–4)","References to external technical standards (NFL 23.321; MS20995CY15; NASM20995CY15) requiring cross‑checking","Alternative compliance path introduced (Requirement 2.b) and a later reinstallation obligation (Requirement 4) creating conditional sequencing","Multiple compliance deadlines (before further flight; within 8 days; within 3 months)","Reference to a Work Card/AMM change (Work Card MF900 26-203 temporary revision TC 115) requiring administrative amendment","Minor textual ambiguity in technical parameter (rupture strength described as \"less than 45 Newtons\") which could cause implementation uncertainty"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This Airworthiness Directive (AD) applies to all Mystère Falcon 900 series aeroplanes and replaces the original AD/AMD 50/30 with Amendment 1.\n- It requires operators and maintenance organisations to inspect, remove or replace, and in some cases reinstall, the safety (lock) wires used on the fire extinguisher selector switches. (See Requirement 1–4.)\n\n**Who is affected**\n\n- Aircraft operators and owners of Mystère Falcon 900 series aircraft.\n- Maintenance organisations, engineers and technicians who perform continuity checks, safety‑wire installation and Aircraft Maintenance Manual (AMM) updates.\n\n**Primary actions required**\n\n- Inspect the safety wires on the fire extinguisher selector switches and remove any wires that do not meet the specified standards (NFL 23.321 or MS20995CY15/NASM20995CY15) (Requirement 1).\n- If not already done, install safety wires that either meet the named standards or are copper wires with a maximum diameter of 0.4 mm and a rupture strength of less than 45 N (Requirement 2; this is presented as an alternative method of compliance).\n- Amend the AMM by incorporating a specified temporary revision to Work Card MF900 26-203 (Requirement 3).\n- If wires were installed under the standard-compliant option in Requirement 2.a, later reinstall wires that meet Requirement 1 standards (Requirement 4).\n\n**Timing (compliance deadlines)**\n\n- The initial inspection (Requirement 1) must have been completed before further flight after the original AD took effect.\n- Installation under Requirement 2 must be done within eight days after this amendment’s effective date.\n- AMM amendment (Requirement 3) must be done within eight days after the original AD became effective.\n- Reinstallation under Requirement 4 must be completed within three months after this amendment’s effective date.\n\n**Official reason given**\n\n- The French aviation authority (DGAC) identified incorrect references on Work Card 26.203 that may have led to the use of incorrect safety wire after continuity checks. The incorrect wire could prevent operation of the fire extinguisher selector switches. The AD therefore directs inspection, removal of incorrect wire and replacement with wires meeting specified standards, plus an AMM change.\n\n**Testing the official purpose against practical effects, costs and risks**\n\n- Who pays: aircraft operators and their maintenance providers bear the direct costs (labour, possible wire replacement, AMM update and aircraft downtime). (See Requirements 1–4 and compliance times.)\n- Who decides and how behaviour changes: CASA's delegate issues the mandatory directive; maintenance staff must inspect, remove non‑complying wire, install compliant wire (or the temporary copper option), and update the AMM. Choice is constrained to the specified wire standards or the alternative copper specification (Requirement 2).\n- Incentives and trade-offs: the AD tightens standards on a small but safety‑critical component (selector switch wiring). Operators face a trade-off between immediate compliance costs (inspection, replacement) and the safety benefit of ensuring the selector switches operate when required. The AD allows a short-term alternative copper specification (Requirement 2.b) which may reduce short‑term supply problems or downtime but is conditional on later reinstating standard‑compliant wire in some cases (Requirement 4), which creates potential double‑work and extra cost.\n- Implementation risk and ambiguity: the alternative allows copper wire with \"a maximum diameter of 0.4 millimetres and can withstand a rupture strength of less than 45 Newtons\" (Requirement 2.b). That wording may be confusing in practice because it specifies a maximum diameter and a maximum (rather than minimum) rupture strength—operators and technicians will need clear interpretation to select appropriate material. Misinterpretation could leave wires that do not perform as intended under operational loads.\n- Compliance burden: short compliance windows (eight days for installation option; three months for reinstallation) impose scheduling pressure on maintenance providers and may cause aircraft ground time.\n- Opportunity costs: time spent inspecting, replacing wires and updating AMM could be used for other maintenance tasks; small operators with limited maintenance capacity may face disproportionate disruption.\n- Effects on markets and private choice: the AD prescribes technical standards (NFL 23.321, MS20995CY15/NASM20995CY15) which restrict the set of acceptable suppliers and products. This reduces freedom to choose alternative materials unless they meet the listed standards or the explicit alternative specification in the AD.\n- Concentrated benefits and diffuse costs: the immediate safety benefit is concentrated on each aircraft’s occupants and operator (clear, tangible), while compliance costs fall directly on operators and their maintenance contractors.\n\n**Reference to the AD text**: see Requirement 1–4 and the Compliance section for deadlines; Background explains the DGAC advisory and the reason for the AD.\n\n**Bottom line**: Mechanically, the AD mandates inspection and correction of the safety wires on fire extinguisher selector switches, requires a specific temporary AMM revision, and provides a narrowly defined alternative wire specification with a later reinstallation requirement. The measure imposes inspection and replacement costs and scheduling pressure on operators and maintenance organisations while aiming to eliminate a configuration that could prevent selector switch operation."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Amendment 1 stays within the original scope of addressing incorrect safety wire on fire extinguisher selector switches. It introduces an alternative compliance method (the 0.4mm/45N specification) and adjusts some deadlines, but does not expand to cover new systems, aircraft types, or unrelated safety issues."},"complexity_factors":["Multiple compliance deadlines referencing both original and amended directive dates (4 separate timing requirements)","Technical specifications requiring cross-reference to external standards (NFL 23.321, MS20995CY15, NASM20995CY15, A-A-59551)","Alternative compliance method with specific physical parameters (0.4mm diameter, <45 Newtons rupture strength)","Conditional logic: Requirement 4 only applies if Requirement 2.a was used","Reference to external French aviation authority document (DGAC AD 2003-084(B) R1)"],"plain_english_summary":"This AD for Mystère Falcon 900 jets requires inspection and, where necessary, replacement of safety wiring on fire‑extinguisher selector switches with approved wire (or specified thin copper wire) and a maintenance‑manual update. It targets potential use of incorrect wire that can jam the selector and prevent extinguisher activation. Compliance is time‑critical under the AD’s short deadlines to ensure onboard fire suppression will operate in an emergency."}},"importantCases":[],"_links":{"self":"/api/acts/ad-amd-50-30-amdt-1-fire-extinguisher-selector-switches","history":"/api/acts/ad-amd-50-30-amdt-1-fire-extinguisher-selector-switches/history","analysis":"/api/acts/ad-amd-50-30-amdt-1-fire-extinguisher-selector-switches/analysis","conflicts":"/api/acts/ad-amd-50-30-amdt-1-fire-extinguisher-selector-switches/conflicts","importantCases":"/api/acts/ad-amd-50-30-amdt-1-fire-extinguisher-selector-switches/important-cases","documents":"/api/acts/ad-amd-50-30-amdt-1-fire-extinguisher-selector-switches/documents"}}