{"id":"F2006B09816","name":"AD/F28/81 Amdt 1 - MLG Attachment Bracket","slug":"ad-f28-81-amdt-1-mlg-attachment-bracket","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54746,"registerId":"commonwealth-F2006B09816-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F28/81 Amdt 1 - MLG Attachment Bracket","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)  \n![](image.002.png)  \nFokker F28 Series Aeroplanes\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/F28/81 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\nAD/F28/81\n\nAmdt 1\n\n  \nMLG Attachment Bracket 3/2001\n\nApplicability: Model F28 Mk. 1000 through Mk. 4000 series, serial numbers 11003 through 11091, 11094 through 11171, 11991, and 11192.\n\nRequirement: 1\\. Inspect the affected area of the upper girder of the MLG bracket and wing stringer fitting in accordance with Parts 2A and 2B of the Accomplishment Instructions of Fokker Service Bulletin (SB) F28/57-90 Revision 1, dated August 28, 2000.\n\n    2. If no cracks were found as a result of the inspection required by the original issue of this Directive, re-inspect in accordance with Requirement 1.\n\n    3. If cracks are found, before further flight, accomplish temporary repairs, and thereafter, depending on crack length, as applicable, perform repetitive inspections at the times specified in Table 1 of this Directive; in accordance with Part 3 of the Accomplishment Instructions of Fokker SB F28/57-90 Revision 1.\n\nNote 1: Replacement of the MLG bracket must be done in accordance with Fokker SB F28/57-92.\n\nNote 2: RLD AD 1999-045/2 refers.\n\nCompliance: For Requirement 1 and 2: Within 12 months after 22 March 2001. Thereafter at intervals not to exceed 18 months.\n\nFor Requirement 3: As per Table 1 below:\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nTABLE 1\n\nCrack Length Repair Instruction Repeat Insp. Interval\n\nLess than 3 mm. Install concentric bushing\\* 18 months\n\nGreater than 3mm, less than 7mm.\n\n  \nInstall eccentric bushing\\* 18 months\n\nGreater than 7mm, less than 15 mm.\n\n  \nRemove cracked part and accomplish repairs\\*\n\n  \n18 months\n\nGreater than 15 mm, less than 25 mm.\n\nGreater than 25 mm, less than 40 mm.\n\n  \n\nAs above 250 flight cycles or 1 month\n\nAs above 50 flight cycles or 1 week\n\nGreater than 40mm. Replace MLG bracket\n\n\\* As an alternative to the above repair action, the MLG bracket may be inspected at intervals not to exceed 250 flight cycles or 1 month, whichever occurs first.\n\nThis amendment becomes effective on 22 March 2001.\n\nBackground: The RLD received a number of reports from F28 operators of cracks discovered in the upper girder of the main landing gear (MLG) bracket, between the stringer fitting bolts, attaching the MLG bracket and fitting to the wing upper skin. Crack surface investigation has shown that the cracking occurred due to stress corrosion.\n\nAmendment 1 is issued in response to a revised RLD AD which introduces repetitive inspections as a result of original inspection findings.\n\nThe original issue of this Airworthiness Directive became effective on 15 July 1999.\n\n![](image.003.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 8 February 2001\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 21 February 2001.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Amendment 1 alters the original AD by introducing mandatory repetitive inspections and a crack‑length based set of repair/inspection actions (see Background and Table 1). The original AD (effective 15 July 1999) is revoked and replaced to require ongoing inspections, temporary repairs before further flight, and specific follow‑up intervals tied to crack size, rather than a one‑off inspection."},"complexity_factors":["Narrow technical applicability: specific aircraft models and a discrete list of serial numbers (Applicability).","Layered inspection regime: initial inspection deadline, recurring 18‑month interval for unaffected parts, and different repetitive intervals after crack detection (Requirement 1–3; Compliance).","Crack‑size dependent repair matrix with multiple outcomes (concentric/ eccentric bushings, part removal, or replacement) and alternate inspection option (Table 1).","Operational safety constraint: temporary repairs required before further flight when cracks are found (Requirement 3).","Cross‑referenced technical documents and procedures: reliance on Fokker Service Bulletins F28/57‑90 Revision 1 and F28/57‑92, plus an RLD AD (Notes 1–2; Requirement).","Mixed metric of compliance: calendar time and flight‑cycle thresholds (Table 1), creating monitoring and record‑keeping burdens.","Revision history: this is an amendment revoking an earlier AD and introducing repetitive inspections based on original findings (Background), which affects continuity of obligations."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Fokker F28 Mk.1000–4000 aircraft (particular serial numbers listed) to inspect the main landing gear (MLG) upper girder and wing stringer fitting for stress‑corrosion cracks, and to carry out repairs or replacements depending on crack length. Inspections must start within 12 months after 22 March 2001 and continue at set intervals. \n\nCASA (by delegate under subregulation 39.1(1)) mandates temporary repairs before further flight when cracks are found and prescribes follow-up actions tied to a crack‑length table; operators bear inspection and repair costs and must follow the referenced Fokker service bulletins."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"This Amendment 1 significantly expanded the original 1999 directive. The original apparently required only a one-time inspection, but this amendment introduces a comprehensive ongoing inspection regime with repetitive inspections, graduated repair requirements based on crack severity, and alternative compliance pathways. The scope shifted from 'inspect once' to 'continuous monitoring with escalating intervention thresholds' — essentially turning a discrete safety check into a long-term structural integrity management program."},"complexity_factors":["Multiple conditional pathways based on crack length findings (6 different crack length thresholds with different actions)","Cross-reference to external technical documents (Fokker Service Bulletins F28/57-90 and F28/57-92)","Dual compliance timelines (calendar-based for Requirements 1-2, flight-cycle OR calendar-based for Requirement 3)","Nested alternative compliance option (asterisked footnote allowing 250 flight cycle/1 month inspections instead of repairs)","Specific serial number applicability list with gaps (11003-11091, 11094-11171, plus two outliers: 11991 and 11192)","Reference to superseded predecessor directive (original AD/F28/81 from 1999) and foreign regulatory reference (RLD AD 1999-045/2 from Netherlands)"],"plain_english_summary":"This CASA safety order requires operators of specified Fokker F28 Mk.1000–4000 series airframes to inspect the main landing-gear-to-wing bracket for stress-corrosion cracking on a mandated schedule, and to ground aircraft until required repairs or replacements are done when cracks are found. It sets inspection intervals and repair thresholds (from sleeving small cracks to bracket replacement for very large cracks) to prevent landing-gear failure and protect flight safety."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f28-81-amdt-1-mlg-attachment-bracket","history":"/api/acts/ad-f28-81-amdt-1-mlg-attachment-bracket/history","analysis":"/api/acts/ad-f28-81-amdt-1-mlg-attachment-bracket/analysis","conflicts":"/api/acts/ad-f28-81-amdt-1-mlg-attachment-bracket/conflicts","importantCases":"/api/acts/ad-f28-81-amdt-1-mlg-attachment-bracket/important-cases","documents":"/api/acts/ad-f28-81-amdt-1-mlg-attachment-bracket/documents"}}