{"id":"F2006B09612","name":"AD/F100/12 - Main Wheel Assembly","slug":"ad-f100-12-main-wheel-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54368,"registerId":"commonwealth-F2006B09612-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F100/12 - Main Wheel Assembly","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)  \nFokker F100 (F28 Mk 100) Series Aeroplanes\n\nAD/F100/12 Main Wheel Assembly 4/99\n\nApplicability: F.28 Mk.0100 aircraft, all serial numbers equipped with ABS Corporation Main Wheel Assembly P/N 5008142-4, Serial numbers APR91-0570 through FEB93-0965.\n\nRequirement: 1. Determine the Part number and Serial number of the Demountable Flange (inboard) Wheel Sub Assembly and the Demountable Flange (outboard) Wheel Sub Assembly.\n\nFor the purposes of this AD, no further action against the Demountable Flange (inboard) Wheel sub assembly is required unless the sub assembly has a Part Number 5008142-4 and a serial number within the following ranges:\n\nAPR91-0570 through OCT92-0858; or\n\nS-APR91-0097 through S-MAY92-0126.\n\nFor the purposes of this AD, no further action against the Demountable Flange (outboard) Wheel sub assembly is required unless the sub assembly has a Part Number 5008140-1 and a serial number within the following ranges:\n\nAPR91-0570 through FEB93-0965; or\n\nS-MAR91-0002 through S-FEB93-0100.\n\nNote 1: Spares of both sub assemblies are affected by the requirements of this AD.\n\n    2. For the inboard Wheel Sub Assemblies, inspect in accordance with Section II - Accomplishment Instructions, Paragraph C of ABS Corporation (ABSC) Service Bulletin SB Fo100-32-46 dated Dec 24, 1992.\n\nFor the outboard Wheel Sub Assemblies , inspect in accordance with Section II \\- Accomplishment Instructions, Paragraph B of ABSC SB Fo100-32-48 dated Mar 10, 1993.\n\nIf damage or cracks are discovered during the inspection on either the inboard or outboard Wheel sub assemblies, then replace the damaged assembly before further flight. Inboard/outboard Wheel sub assemblies affected by this AD may be used as suitable replacements, provided Requirement 3 of this AD has been completed prior to fitment.\n\n    3. Repair the inboard Wheel Sub Assembly in accordance with Section II - Accomplishment Instructions, Paragraph D of ABSC SB Fo100-32-46 dated Dec 24, 1992.\n\nRepair the outboard Wheel Sub Assembly in accordance with Section II \\- Accomplishment Instructions, Paragraph C of ABSC Fo100-32-48 dated Mar 10, 1993.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nNote 2: The repair of the Outboard Wheel sub assembly in accordance with the above constitutes terminating action for this AD. However, the applicable Component Maintenance Manual contains continuing inspection requirements.\n\n    4. Inspect the Inboard Wheel Sub Assembly in accordance with Section II - Accomplishment Instructions, Paragraphs B.1 and C of ABSC SB Fo100-32-46 dated Dec 24, 1992.\n\nNote 3: RLD BLA 93-009/3(A) refers.\n\nNote 4: Fokker Service Bulletins F100-32-070 and F100-32-073 refer.\n\nCompliance: 1. Within 3 months after the effective date of this AD.\n\n    2. For wheel assemblies with less than 800 flight cycles, inspect before 900 flight cycles, or within 200 flight cycles or at the next tyre chance, whichever occurs first.\n\nFor wheel assemblies with greater than 800 flight cycles, inspect within the next 100 flight cycles or at next tyre change, whichever occurs first.\n\nIn both cases, reinspect no later than every 500 flight cycles or at each tyre change, whichever occurs first. Continue to inspect until Requirement 3 of this AD becomes effective.\n\n    3. After the third inspection under Requirement 2 of this AD and before further flight after that inspection.\n\n    4. At the next two tyre changes after being repaired in accordance with Requirement 3 of this AD. Thereafter at every Wheel Assembly overhaul.\n\nThis Airworthiness Directive becomes effective on 22 April 1999.\n\nBackground: Several F.28 Mk.0100 operators reported finding cracks and broken spokes on Main Wheel Assemblies P/N 5008131-4. Investigation revealed that the manufacturer of the wheels, ABS Corporation, had discontinued a shot-peening procedure which was part of the manufacturing process before April 1991. As a result, a number of units were produced which are prone to fretting and cracking, due to the lack of shot- peening of the assembly mating surfaces and bolt bosses.","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"},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific manufacturing defect in a specific aircraft type. The scope remains precisely limited to the identified wheel assemblies and does not appear to have expanded beyond the original safety concern."},"complexity_factors":["Multiple nested conditional requirements (Requirements 1-4 with cross-dependencies — e.g., Requirement 3 must be completed before certain replacements allowed)","Dual-track compliance paths for inboard vs. outboard wheel sub-assemblies with different part numbers, serial number ranges, and service bulletins","Complex compliance timing with multiple variables: flight cycles, tyre changes, calendar dates, and 'whichever occurs first' logic","Four separate serial number ranges to check across two different part numbers","External document incorporation by reference (two ABS Corporation service bulletins and two Fokker service bulletins) without reproducing their content","Technical aviation terminology requiring specialized knowledge (e.g., 'shot-peening', 'demountable flange', 'terminating action')","Conditional exemption language ('no further action... unless') creating negative logic that must be parsed carefully"],"plain_english_summary":"This Airworthiness Directive orders operators of certain Fokker F100s to inspect and repair specific ABS Corporation main landing wheels manufactured without shot‑peening (Apr 1991–Feb 1993). Affected operators and maintenance crews must verify wheel identity, inspect for cracking per the manufacturer's instructions, and repair or replace cracked wheels before flight. It prevents catastrophic wheel spoke failure on landing or takeoff."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The AD addresses an identified unsafe condition arising from a specific manufacturing change (discontinuation of shot-peening) and targets particular part numbers and serial-number ranges. The measures — identification, inspection, repair/replace, and specified compliance intervals — are narrowly tailored to that technical problem. The directive extends to spares and establishes inspection/repair sequences, but these are consistent with correcting the original safety issue rather than expanding the AD to unrelated matters. Therefore the scope has not grown significantly beyond its original safety-focused purpose."},"complexity_factors":["Multiple conditional serial-number ranges for both inboard and outboard sub-assemblies (APR91–0570 through FEB93–0965 and several 'S-' prefixed ranges) in Requirement 1","Different part numbers for inboard (P/N 5008142-4) and outboard (P/N 5008140-1) assemblies with separate inspection/repair instructions","Cross-reference to two ABS service bulletins with specific paragraphs for different sub-assembly actions (SB Fo100-32-46 and SB Fo100-32-48)","Staggered and conditional compliance windows tied to flight cycles and tyre-change events (initial timing depends on whether assembly has <800 or >800 flight cycles; repeat intervals specified)","A terminating action for outboard repair (Note 2) but continuing inspection obligations in the Component Maintenance Manual (creates layers of compliance)","Notes referring to other service bulletins and documents (Fokker SBs and RLD reference), increasing off-document navigation","Conditional allowance to use affected sub-assemblies as replacements only if Requirement 3 has been completed prior to fitment (creates an exception-to-exception workflow)"],"plain_english_summary":"**What this directive does (mechanically)\n\n- Identifies a specific set of Fokker F100 (F28 Mk 100) main wheel sub-assemblies by part number and serial-number ranges and requires operators to inspect, repair or replace them. (See Requirement 1–4.)\n\n- Requires initial identification of the part and serial number of both the inboard and outboard demountable flange wheel sub-assemblies on affected aeroplanes, and says which serial-number ranges are subject to the remainder of the directive (Requirement 1).\n\n- Requires inspections of the inboard and outboard wheel sub-assemblies following the detailed procedures in two ABS Corporation Service Bulletins (SB Fo100-32-46 and SB Fo100-32-48) (Requirement 2). If cracks or damage are found, the damaged assembly must be replaced before further flight.\n\n- Requires repair actions, where specified, also following the ABS service bulletins (Requirement 3). Repair of the outboard wheel sub-assembly is identified as terminating action for this AD, but the Component Maintenance Manual still requires ongoing inspections (Note 2).\n\n- Specifies ongoing inspection timing: initial and repetitive inspection intervals that depend on flight cycles and tyre-change events, and a requirement to re-inspect until the repair requirement becomes effective (Compliance section for Requirement 2 and 4).\n\n- States the AD’s effective date and gives background that the unsafe condition stems from a manufacturing change (discontinuation of shot-peening before April 1991) that makes some wheels prone to fretting and cracking (Background).\n\nWho this affects\n\n- Aircraft operators and owners of Fokker F100 (F28 Mk 100) aeroplanes that have ABS Corporation Main Wheel Assembly P/N 5008142-4 (inboard) and P/N 5008140-1 (outboard) with the serial numbers listed in Requirement 1.\n- Maintenance organisations and engineers who perform inspections, repairs and parts identification.\n- Parts suppliers and stock-holders of the listed wheel sub-assemblies (Note: spares are explicitly affected).\n\nWhy it matters (purpose claimed by the AD and practical consequences)\n\n- Purpose claimed: to prevent wheel failures caused by cracking and broken spokes after ABS Corporation discontinued a shot-peening step in manufacture, which increased susceptibility to fretting and cracking (Background).\n- Practical consequences: aircraft with affected parts must be checked or grounded until inspected/ repaired or replaced if cracks are found. This imposes direct costs on operators (labour for inspections, possible replacement parts, aircraft downtime) and ongoing inspection costs where repairs are not a permanent end to inspections (the Component Maintenance Manual retains inspection obligations — Note 2).\n\nMechanics, incentives and trade-offs (how it changes behaviour and who decides/pays)\n\n- Who pays: aircraft operators/owners pay for inspections, repairs, replacements, and associated downtime. Maintenance organisations charge for labour and parts.\n- Who decides: the AD requires operators to follow the specified inspection and repair procedures in the ABS service bulletins; maintenance organisations make the practical decisions on scheduling and carrying out the work. The AD prescribes mandatory compliance timings.\n- Behaviour change: operators must identify affected wheels, schedule and perform the inspections at the intervals set (dependent on flight cycles or tyre changes), and replace or repair wheel sub-assemblies that show damage before further flight. Outboard-wheel repair is a terminating action for the AD (but not for all inspections) and inboard repairs have specified follow-up inspections (Requirement 3 and Note 2).\n\nCosts, compliance burden and implementation risks\n\n- Direct costs: inspection labour, possible replacement wheel sub-assemblies or repairs, and aircraft downtime while inspections/repairs are completed.\n- Recurring costs: the AD requires repeated inspections until the terminating action is achieved for outboard wheels; even then, the Component Maintenance Manual requires continuing inspections — so there may be ongoing maintenance cost.\n- Scheduling friction: inspection intervals tied to flight cycles and tyre changes can force earlier maintenance than planned and may cluster with other scheduled work (Compliance for Requirement 2 and 4).\n- Implementation risks: reliance on correct part/serial identification and correct execution of SB procedures; availability of spare parts or approved repair facilities could constrain timely compliance.\n\nConcentrated benefits and diffuse costs\n\n- Benefit is concentrated to operators of affected F100 aeroplanes (reduced risk of wheel failure); cost is borne by those same operators in terms of maintenance expense and downtime. The AD affects spare-stock holders because spares are explicitly included (Requirement 1, Note 1).\n\nCross-references and required documents\n\n- The AD directs compliance with specific paragraphs of ABS Corporation Service Bulletins: SB Fo100-32-46 (Dec 24, 1992) and SB Fo100-32-48 (Mar 10, 1993) for inspection and repair instructions (Requirements 2 and 3).\n- It also references the Component Maintenance Manual for continuing inspection requirements and several Fokker service bulletins in advisory notes (Note 2–4).\n\nKey sections to consult in the AD\n\n- Requirement 1: Part and serial-number identification and which serial ranges are subject to further action.\n- Requirement 2: Inspection procedures and intervals (with conditional timing dependent on flight cycles and tyre changes).\n- Requirement 3: Repair instructions and the statement that outboard repair is terminating action for the AD.\n- Requirement 4: Post-repair inspection timing.\n- Background: manufacturing change (shot-peening discontinued) and the safety rationale.\n"}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-12-main-wheel-assembly","history":"/api/acts/ad-f100-12-main-wheel-assembly/history","analysis":"/api/acts/ad-f100-12-main-wheel-assembly/analysis","conflicts":"/api/acts/ad-f100-12-main-wheel-assembly/conflicts","importantCases":"/api/acts/ad-f100-12-main-wheel-assembly/important-cases","documents":"/api/acts/ad-f100-12-main-wheel-assembly/documents"}}