{"id":"F2006B07224","name":"AD/SWSA226/81 - Generator System Rework","slug":"ad-swsa226-81-generator-system-rework","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49029,"registerId":"commonwealth-F2006B07224-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SWSA226/81 - Generator System Rework","content":"![](image.001.png)  \nFairchild (Swearingen) SA226 and SA227 Series Aeroplanes\n\nAD/SWSA226/81 Generator System Rework 10/97\n\nApplicability: SA226-T Serial Nos: T201 through T275 and T277 through T291 inclusive. SA226-T(B) Serial Nos: T(B)276 and T(B)292 through T(B)417 inclusive. SA226-AT Serial Nos: AT001 through AT074 inclusive.\n\nSA226-TC Serial Nos: TC201 through TC419 inclusive. SA227-TT Serial Nos: TT421 through TT541 inclusive. SA227-AT Serial Nos: AT423 through AT631 inclusive.\n\nSA227-AC Serial Nos: AC406, AC415, AC416, AC420 through AC705 inclusive and AC707 through AC733 inclusive.\n\nRequirement: To prevent failure of both generators during critical phases of flight (such as night operation or while in icing conditions), which could result in loss of control of the aircraft, accomplish the following:\n\n    (a) For the model and serial number aircraft presented below, replace the existing generator fault transformer wiring with new dual conductor shielded wire in accordance with Fairchild Service Bulletin (SB) 226-24-027, Issued: 19 May, 1988, Revised: 22 February, 1989, or Fairchild SB 227-24-008, Issued: 18 March 1988, Revised: 22 February 1989, as applicable.\n\n    (1) Model SA226-T aircraft, serial numbers T201 through T275 inclusive and T277 through T291 inclusive;\n\nModel SA226-T(B) aircraft, serial numbers T(B)276 and T(B)292 through T(B)417 inclusive;\n\nModel SA226-AT aircraft, serial numbers AT001 through AT074 inclusive; and\n\nModel SA226-TC aircraft, serial numbers TC201 through TC419 inclusive.\n\n    (2) Model SA227-TT aircraft, serial numbers TT421 through TT541 inclusive;\n\nModel SA227-AT aircraft, serial numbers AT423 through AT631 inclusive; and\n\nModel SA227-AC aircraft, serial numbers AC406, AC415, AC416, and AC420 through AC683 inclusive.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n    (b) For the model and serial number aircraft presented below, rewire the electrical power generation system to reduce the possibility of 325-amp current limiter failure in accordance with Fairchild SB 226-24-023, Issued: 25 October, 1985, Revised: 23 January, 1989, or Fairchild SB 227-24-005, Issued: 25 October, 1985, Revised: 23 January, 1989, as applicable.\n\n    (1) Model SA226-T aircraft, serial numbers T249 through T275 inclusive and T277 through T291 inclusive;\n\nModel SA226-T(B) aircraft, serial numbers T(B)276 and T(B)292 through T(B)417 inclusive;\n\nModel SA226-AT aircraft, serial numbers ATO25 through ATO74 inclusive; and\n\nModel SA226-TC aircraft, serial numbers TC209 through TC419 inclusive.\n\n    (2) Model SA227-TT aircraft, serial numbers TT421 through TT541 inclusive;\n\nModel SA227-AT aircraft, serial numbers AT423 through AT591 inclusive; and\n\nModel SA227-AC aircraft, serial numbers AC420 through AC594 inclusive.\n\n    (c) For the model and serial number aircraft presented below modify the voltage regulator access panel and install a connector in the wire bundle in accordance with Fairchild SB 226-24-026, Issued: May 27, 1987:\n\nModel SA226-T aircraft, serial numbers T249 through T275 inclusive and T277 through T291 inclusive;\n\nModel SA226-T(B) aircraft, serial numbers T(B)276 and T(B)292 through T(B)417 inclusive;\n\nModel SA226-AT aircraft, serial numbers ATO25 through ATO74 inclusive; and\n\nModel SA226-TC aircraft, serial numbers TC209 through TC419 inclusive,\n\n    (d) For the model and serial number aircraft presented below install new voltage regulators, reroute certain wires, and replace the entire voltage regulator panel assembly in accordance with Fairchild SB 24-018, Issued: October 22, 1980, Revised: January 7, 1981:\n\nModel SA226-T aircraft, serial numbers T201 through T275 inclusive and T277 through T291 inclusive;\n\nModel SA226-T(B) aircraft, serial numbers T(B)276 and T(B)292 through T(B)347 inclusive;\n\nModel SA226-AT aircraft, serial numbers ATO01 through ATO74 inclusive; and\n\nModel SA226-TC aircraft, serial numbers TC201 through TC348.\n\n    (e) For the model and serial number aircraft presented below, modify the direct current (DC) generator control system so that it will operate off its respective generator output in accordance with Fairchild SB 22624-031, dated\n\nJuly 27, 1989, or Fairchild SB 227-24-012, Issued: May 4, 1989; Revised: July 27, 1989, as applicable. This includes removing field current and reset resistors, removing the reset and generator relays and associated diodes, installing a 10-amp generator control circuit breaker to the left-hand and right- hand essential bus panels, and replacing the 10-amp generator control circuit breakers in the left-hand and right-hand wheelwells with 15-amp circuit breakers that are wired in series with the generator control circuit breakers.\n\n    (1) Model SA226-T aircraft, serial numbers T249 through T275 inclusive and T277 through T291 inclusive;\n\nModel SA226-T(B) aircraft, serial numbers T(B)276 and T(B)292 through T(B)417 inclusive;\n\nModel SA226-AT aircraft, serial numbers ATO25 through ATO74 inclusive; and\n\nModel SA226-TC aircraft, serial numbers TC209 through TC419 inclusive.\n\n    (2) Model SA227-TT aircraft, serial numbers TT421 through TT541 inclusive;\n\nModel SA227-AT aircraft, serial numbers AT423 through AT695 inclusive; and\n\nModel SA227-AC aircraft, serial numbers AC406, AC4 1 5, AC416, AC420 through AC556 inclusive, AC558 through AC705 inclusive, and AC707 through AC733 inclusive.\n\nNote: FAA AD 97-11-13 Amdt 39-10042 refers.\n\nCompliance: Unless already accomplished to be incorporated within the next 2,000 hours time-in- service after the effective date of this AD.\n\nThis airworthiness directive becomes effective on 11September 1997.\n\nBackground: FAA has received reports of both generators going off-line during flight on three of the affected aircraft. The actions specified by this AD are intended to prevent failure of both generators during critical phases of flight (such as night operations or in icing conditions), which may result in the loss of control of the aircraft.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The AD keeps scope aligned with its original safety objective: preventing dual-generator failure for the listed SA226/SA227 serial-number groups. It consolidates several service-bulletin remedies and applies different measures to specific serial ranges, but does not expand applicability beyond the aircraft and serial numbers identified in the instrument."},"complexity_factors":["Multiple aircraft models and many non-contiguous serial-number ranges, producing varied applicability per action","Several distinct corrective actions (rewiring, transformer wiring replacement, regulator/panel replacement, generator-control reconfiguration, circuit-breaker changes)","Requirement to follow multiple different Fairchild Service Bulletins, some with revisions and differing issue dates","Safety-critical electrical work requiring certified maintenance facilities and possible parts swaps","Staged applicability where different serial ranges require different combinations of fixes","Cross-reference to FAA AD and historical service-bulletin revisions increases regulatory/technical cross-checking","Compliance deadline tied to flight hours (2,000 hours), requiring operational planning and potential downtime"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specified Fairchild SA226 and SA227 aircraft (listed by serial number) to carry out electrical modifications: rewiring, shielded conductors, voltage-regulator and generator-control changes, panel/component replacements and circuit-breaker changes, following the named Fairchild Service Bulletins. The operator pays for the work, which must be done by certified maintenance organisations and completed within 2,000 flight hours. The AD’s stated purpose is to reduce the risk of both generators going offline during critical flight phases and the resulting risk of loss of control."},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":false,"description":"This AD maintains its original scope as a targeted safety directive addressing specific generator system failures in defined aircraft serial numbers. The multiple requirements reflect the technical complexity of the electrical system fix rather than scope creep."},"complexity_factors":["Multiple overlapping applicability groups with different serial number ranges for each aircraft model","Five distinct technical modification requirements (a)-(e) with different applicability matrices","Cross-references to six different Fairchild Service Bulletins with specific issue/revision dates","Nested serial number ranges with gaps (e.g., T201-T275 and T277-T291, excluding T276)","Technical aviation terminology requiring specialized knowledge (current limiters, voltage regulators, essential bus panels, wheelwells)","Conditional applicability where some aircraft may fall under multiple requirements while others fall under only one","Specific compliance deadline tied to flight hours rather than calendar date"],"plain_english_summary":"CASA mandates electrical-system modifications on specified Fairchild Swearingen SA226/SA227 aircraft to prevent dual generator failures. It affects owners/operators of the listed serial-numbered models and requires those modifications within 2,000 flight hours.\n\nThe AD addresses a known defect that caused three dual-generator outages and could leave an aircraft without critical instruments, significantly reducing the risk of catastrophic loss."}},"importantCases":[],"_links":{"self":"/api/acts/ad-swsa226-81-generator-system-rework","history":"/api/acts/ad-swsa226-81-generator-system-rework/history","analysis":"/api/acts/ad-swsa226-81-generator-system-rework/analysis","conflicts":"/api/acts/ad-swsa226-81-generator-system-rework/conflicts","importantCases":"/api/acts/ad-swsa226-81-generator-system-rework/important-cases","documents":"/api/acts/ad-swsa226-81-generator-system-rework/documents"}}