{"id":"F2006B11350","name":"AD/MU-2/21 Amdt 1 - Outer Fuel Tank Switch Wiring - Modification","slug":"ad-mu-2-21-amdt-1-outer-fuel-tank-switch-wiring-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57240,"registerId":"commonwealth-F2006B11350-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/MU-2/21 Amdt 1 - Outer Fuel Tank Switch Wiring - Modification","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)  \nMitsubishi MU-2 Series Aeroplanes\n\nAD/MU-2/21\n\nAmdt 1\n\n  \nOuter Fuel Tank Switch Wiring \\- Modification 10/84\n\nApplicability: All models MU-2B-25/-26/-26A/-35/-36A/-40/-60. Aircraft which have previously complied with SR017/28- 001 dated 25 July 1979. Model MU-2B-40. S/Nos. 395SA thru 412SA, 414SA and 416SA. Model MU-2B-60. S/Nos. 731SA thru 747SA and 749SA thru 757SA.\n\nRequirement: Mitsubishi SB No. SB013/28-001 or SB014/28-002 as applicable. Compliance: Within the next 100 hours time in service after 31 January 1980.\n\nBackground: a. To prevent the possibility of fuel being transferred overboard either on the ground or in flight from the outer tanks when the FUEL/TRANSFER switch is in TIP MAN and the outer pump switch is placed in MANUAL.\n\nb. Amendment 1 is to clarify “Applicability” due to entry of an additional Model to the Australian Register.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a narrow, technical airworthiness directive focused on a specific wiring modification for one aircraft type. Amendment 1 merely clarifies which aircraft models are covered due to new entries on the Australian register. The scope remains tightly constrained to the original safety purpose — preventing inadvertent fuel dumping from outer tanks."},"complexity_factors":["Single, specific technical requirement referencing external manufacturer service bulletins","Limited applicability section with explicit serial number ranges for two models","Simple compliance deadline (100 hours time in service after fixed date)","No defined terms section, no cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Straightforward two-paragraph background explanation","Amendment 1 adds only a minor clarification about model applicability"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific repairs or modifications to aircraft.\n\n**What it does:**\nThis directive orders owners and operators of specific **Mitsubishi MU-2 series aeroplanes** to modify the wiring for their outer fuel tank switches. The fix prevents a dangerous situation where fuel could accidentally dump overboard (on the ground or in flight) when certain fuel transfer switches are used incorrectly.\n\n**Who it affects:**\n- Owners and operators of Mitsubishi MU-2B-25, -26, -26A, -35, -36A, -40, and -60 model aircraft\n- Specifically excludes aircraft that already complied with an earlier service bulletin (SR017/28-001 from July 1979)\n- For MU-2B-40 models: serial numbers 395SA through 412SA, 414SA, and 416SA\n- For MU-2B-60 models: serial numbers 731SA through 747SA and 749SA through 757SA\n\n**What must be done:**\n- Follow Mitsubishi Service Bulletin SB013/28-001 or SB014/28-002 (whichever applies to your specific aircraft)\n- Complete the modification within **100 hours of flight time** after 31 January 1980\n\n**Why it matters:**\nUncontrolled fuel dumping creates fire hazards and can leave aircraft without enough fuel to reach their destination. This directive closes a safety gap in the fuel transfer system controls."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 modifies the instrument’s scope by clarifying the Applicability section to include an additional model that entered the Australian Register. The AD therefore alters which aircraft are covered by explicitly expanding/clarifying the set of affected aeroplanes (Background b; Applicability)."},"complexity_factors":["Technical subject matter (aircraft fuel transfer wiring) requiring specialist maintenance skills and reference to manufacturer service bulletins (Requirement).","Multiple affected model types and specific serial-number ranges that operators must check (Applicability).","Mandatory compliance tied to an absolute service-hours window measured from a fixed date (100 hours after 31 January 1980) rather than a calendar deadline (Compliance).","Dependence on external documents (Mitsubishi SB013/28-001 or SB014/28-002) for the exact technical steps (Requirement).","Amendment changes applicability which requires operators to verify whether a newly entered model is covered (Background b)."],"plain_english_summary":"This CASA airworthiness directive requires owners/operators of specified Mitsubishi MU‑2 models and serial ranges to have a wiring modification to the outer fuel tank switch system carried out per Mitsubishi service bulletin SB013/28‑001 or SB014/28‑002. The one‑off change must be completed within 100 hours TIS after 31 January 1980 to prevent possible fuel being transferred overboard; owners/operators bear the cost."}},"importantCases":[],"_links":{"self":"/api/acts/ad-mu-2-21-amdt-1-outer-fuel-tank-switch-wiring-modification","history":"/api/acts/ad-mu-2-21-amdt-1-outer-fuel-tank-switch-wiring-modification/history","analysis":"/api/acts/ad-mu-2-21-amdt-1-outer-fuel-tank-switch-wiring-modification/analysis","conflicts":"/api/acts/ad-mu-2-21-amdt-1-outer-fuel-tank-switch-wiring-modification/conflicts","importantCases":"/api/acts/ad-mu-2-21-amdt-1-outer-fuel-tank-switch-wiring-modification/important-cases","documents":"/api/acts/ad-mu-2-21-amdt-1-outer-fuel-tank-switch-wiring-modification/documents"}}