{"id":"F2005L01038","name":"AD/F100/64 - Main Landing Gear Main Fitting - 3","slug":"ad-f100-64-main-landing-gear-main-fitting-3","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":34575,"registerId":"commonwealth-F2005L01038-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Fokker F100 (F28 Mk 100) Series Aeroplan","sectionType":"division","heading":"Fokker F100 (F28 Mk 100) Series Aeroplanes","content":"### Fokker F100 (F28 Mk 100) Series Aeroplanes\n\n| AD/F100/64 | Main Landing Gear Main Fitting - 3 | 6/2005 |\n| ---------- | ---------------------------------- | ------ |\n\n| Applicability: | Model F.28 Mk 0100 and Mk 0070 aircraft, all serial numbers, if equipped with Messier-Dowty (formerly Dowty Aerospace Gloucester) MLG units.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Inspect and, as necessary, repair both MLG Main Fittings in accordance with the Accomplishment Instructions of Messier-Dowty Service Bulletin (SB) F100-32-106 dated 18 February 2005, or later UK CAA approved revision.Whenever cracks are found, determine whether (and for how many) flights may be continued, prior to repair or replacement, in accordance with the crack size and location thresholds as specified in Fokker Services SB F100-32-141 dated 18 February 2005, or later CAA-NL approved revision.Irrespective of the inspection results, within 7 days after accomplishment of the inspection, report all findings to Fokker Services.Note: CAA-NL AD NL-2005-002 refers. |\n| Compliance:    | Within 2,000 flight cycles since the last inspection in accordance with Messier-Dowty SB F100-32-104 Revision 2, and Fokker Services SB F100-32-137 (as required by AD/F100/55 Amdt 1; CAA-NL AD 2002-115/2 refers), or within 3 months after 9 June 2005, whichever occurs later.                                                                                                                                                                                                                                                                                                                                                                                                             |\n|                | This Airworthiness Directive becomes effective on 9 June 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background:    | Recently, an empty Fokker 100, which was being moved for maintenance, suffered a failure of the left hand MLG Main Fitting. The MLG Main Fitting broke into two pieces, whereby the lower part including the Sliding Member, Wheels and Brakes separated from the upper Main Fitting part. Preliminary findings indicate failure due to a fatigue crack in the Main Fitting. AD/F100/55 Amdt 1 (CAA-NL AD2002-115/2) still applies, and although this Directive requires a second one-time inspection for cracks, the CAA-NL still consider this to be an interim action.                                                                                                                      |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n29 April 2005","sortOrder":0},{"sectionNumber":"AD/F100/64","sectionType":"part","heading":"AD/F100/64","content":"## AD/F100/64","sortOrder":1},{"sectionNumber":"Main Landing Gear Main Fitting - 3","sectionType":"part","heading":"Main Landing Gear Main Fitting - 3","content":"## Main Landing Gear Main Fitting - 3","sortOrder":2},{"sectionNumber":"6/2005","sectionType":"part","heading":"6/2005","content":"## 6/2005","sortOrder":3}],"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":4,"scope_assessment":{"changed":true,"description":"This AD expands the regulatory actions beyond the earlier inspection regime by requiring a second one‑time inspection specifically targeting fatigue cracks in the MLG main fittings, adding explicit repair/replace instructions tied to Messier‑Dowty and Fokker service bulletins, imposing a mandatory 7‑day reporting obligation to Fokker Services, and specifying conditional continued‑flight criteria. In short, it supplements and narrows focus relative to prior AD(s) by adding an extra inspect/repair/report step and by formalising allowable ferry‑flight rules pending repair."},"complexity_factors":["Applicability limited to Fokker F.28 Mk 0100 and Mk 0070 aircraft fitted with Messier‑Dowty MLG units (conditional applicability)","Multiple external documents referenced (Messier‑Dowty SB F100‑32‑106, Messier‑Dowty SB F100‑32‑104 Rev 2, Fokker SB F100‑32‑137, Fokker SB F100‑32‑141) requiring operators to use the correct, CAA‑approved revisions","Cross‑references to earlier ADs (AD/F100/55 Amdt 1; CAA‑NL AD2002‑115/2) that remain in force","Conditional logic on allowable continued flights based on crack size/location thresholds contained in another document (delegated technical judgment)","Dual timing formula for compliance (2,000 flight cycles since last specified inspection OR within 3 months after 9 June 2005, whichever is later)","A mandatory reporting requirement within a short fixed window (7 days) irrespective of inspection outcome"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Requires operators of Fokker F100 (F28 Mk 100 / Mk 0070) aeroplanes that are fitted with Messier‑Dowty main landing gear (MLG) units to inspect both main landing gear main fittings for cracks and to carry out any repairs specified by the manufacturer service instructions. (Requirement)\n- If cracks are found, the operator must use the crack‑size/location thresholds in the Fokker service bulletin to decide whether the aircraft may be flown further and for how many flights before repair or replacement is required. (Requirement)\n- Regardless of whether cracks are found, the operator must report the inspection findings to Fokker Services within 7 days of completing the inspection. (Requirement)\n- The inspections must be performed in accordance with the Messier‑Dowty Service Bulletin F100‑32‑106 (or a later UK CAA‑approved revision) and the crack‑continuation criteria in Fokker Services SB F100‑32‑141 (or a later CAA‑NL approved revision). (Requirement)\n\n**Who it applies to**\n\n- All serial numbers of Fokker F.28 Mk 0100 and Mk 0070 aircraft, but only those fitted with Messier‑Dowty (formerly Dowty Aerospace Gloucester) MLG units. (Applicability)\n\n**When it must be done**\n\n- The inspection must be completed within 2,000 flight cycles since the last inspection carried out under earlier Messier‑Dowty and Fokker service bulletins noted in the AD, or within 3 months after 9 June 2005, whichever is later. (Compliance)\n\n**Why the regulator issued this AD (stated rationale)**\n\n- The AD follows a reported fatigue failure of a left‑hand MLG main fitting on a Fokker 100 that broke into two pieces while the aircraft was being moved for maintenance. The preliminary finding pointed to a fatigue crack in the main fitting. The AD is described by the CAA‑NL as an interim action and supplements earlier required inspections. (Background)\n\n**Who pays**\n\n- Aircraft operators bear the direct costs: performing the inspections, any repairs or replacements, the labour and downtime, and any parts supplied by Messier‑Dowty or other approved sources. Operators also must complete and submit the report to Fokker Services. (Requirement)\n\n**Who decides and what judgment is required**\n\n- Licensed maintenance organisations and their certifying staff carry out the inspections and make the on‑aircraft determinations. If cracks are found, those maintainers (using the crack‑size/location thresholds in Fokker SB F100‑32‑141) decide if the aircraft may be flown further and for how many flights before repair or replacement is required. The regulator enforces compliance with the AD and requires use of CAA‑approved revisions of the referenced service bulletins. (Requirement)\n\n**Behavioural and operational effects**\n\n- Operators must schedule and complete a one‑time inspection of both main fittings; this can cause aircraft downtime and maintenance costs. If cracks are discovered, repairs or replacement will impose immediate maintenance actions and potentially longer groundings. If the thresholds permit continued flight for a limited number of flights, operators face a management decision balancing operational needs against safety margins and repair scheduling. The reporting requirement centralises fault data with Fokker Services.\n\n**Trade‑offs, risks and implementation notes**\n\n- Costs and incentives: The AD imposes a concentrated cost on affected operators (inspection/repair/downtime) while the benefit — reduced risk of in‑service failure — is diffuse across passengers and the public. The manufacturer and component supplier may gain replacement/repair work.\n- Dependence on external documents: Compliance depends on following specific manufacturer service bulletins and their later CAA‑approved revisions; operators must have access to those documents and interpret them correctly. (Requirement)\n- Discretion and judgement: The AD delegates a safety‑critical operational judgment (whether an aircraft may be ferried for further flights after a crack is found and for how many flights) to maintainers using the Fokker SB thresholds. That creates an implementation risk if thresholds are misapplied or ambiguous. (Requirement)\n- Reporting and data centralisation: Mandatory reporting to Fokker Services within 7 days supports trend analysis but requires administrative effort by operators. (Requirement)\n- Interaction with earlier directives: This AD supplements earlier AD/F100/55 Amdt 1 (CAA‑NL AD2002‑115/2) rather than replacing it; operators must ensure they remain compliant with both instruments and the referenced service bulletins. (Background / Compliance)\n\n**Net practical effect**\n\n- If you operate an affected Fokker 100 with Messier‑Dowty MLG, you must inspect both main fittings within the stated compliance window, follow the specified service bulletins for repairs, use the Fokker criteria to determine any allowable ferry flights after crack detection, and report results to Fokker Services. The immediate effect is an added maintenance obligation and reporting duty, with associated direct costs to operators and potential operational disruption."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical failure mode in a defined aircraft type. The scope remains tightly focused on the original safety concern — fatigue cracking in MLG main fittings — without expansion into unrelated systems or broader operational requirements."},"complexity_factors":["Multiple cross-referenced technical documents: requires compliance with specific revisions of Messier-Dowty SB F100-32-106 and Fokker Services SB F100-32-141, plus references to prior AD/F100/55 Amdt 1 and CAA-NL AD 2002-115/2","Conditional logic for crack findings: operators must apply different procedures based on crack size and location using thresholds from a separate document","Dual compliance timeframe calculation: 'whichever occurs later' creates a conditional deadline based on individual aircraft inspection history","Mandatory reporting requirement irrespective of findings: creates an unconditional obligation separate from the conditional repair requirements","International regulatory layering: references Dutch aviation authority (CAA-NL) directives, requiring operators to track foreign regulatory actions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's aviation regulator (CASA) for specific aircraft.\n\n**What it does:**\nOrders airlines and aircraft operators to inspect the **main landing gear** (the wheels that support the plane when it lands) on certain **Fokker F100 aircraft**. Specifically, it targets the \"Main Fitting\" — a critical structural component that holds the landing gear together.\n\n**Why it matters:**\nA Fokker 100 aircraft recently suffered a serious failure where this exact part snapped in two while the plane was being moved for maintenance. The investigation found **fatigue cracks** (tiny fractures that develop over time from repeated stress) were the likely cause. If undetected, these cracks could cause the landing gear to collapse during landing or taxiing.\n\n**Who must comply:**\nOperators of Fokker F100 and F70 aircraft equipped with **Messier-Dowty** landing gear units (regardless of serial number).\n\n**What operators must do:**\n- **Inspect** both main landing gear main fittings following specific technical instructions from the manufacturer (Messier-Dowty Service Bulletin F100-32-106)\n- **Repair** any damage found\n- If cracks are found, determine whether the aircraft can keep flying temporarily (and for how many flights) using separate guidelines from Fokker Services\n- **Report all findings** to Fokker Services within 7 days of inspection, even if nothing is wrong\n\n**When to do it:**\nWithin 2,000 flight cycles since the last required inspection, **or** within 3 months after 9 June 2005 — whichever comes later.\n\n**Key point:** This directive is labeled \"interim action\" — meaning regulators consider it a temporary fix while they work on a permanent solution."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-64-main-landing-gear-main-fitting-3","history":"/api/acts/ad-f100-64-main-landing-gear-main-fitting-3/history","analysis":"/api/acts/ad-f100-64-main-landing-gear-main-fitting-3/analysis","conflicts":"/api/acts/ad-f100-64-main-landing-gear-main-fitting-3/conflicts","importantCases":"/api/acts/ad-f100-64-main-landing-gear-main-fitting-3/important-cases","documents":"/api/acts/ad-f100-64-main-landing-gear-main-fitting-3/documents"}}