{"id":"F2005L03899","name":"AD/F100/53 Amdt 2 - Main Landing Gear Sliding Member","slug":"ad-f100-53-amdt-2-main-landing-gear-sliding-member","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39675,"registerId":"commonwealth-F2005L03899-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/F100/53 Amdt 2 | Main Landing Gear Sliding Member | 1/2006 |\n| ----------------- | -------------------------------- | ------ |\n\n| Applicability: | All Model F.28 Mk. 0100 and Mk. 070 aircraft, equipped with Dowty or Messier-Dowty Main Landing Gear Part number 201072011, 201072012, 201072013, 201072014, 201072015, or 201072016, which include sliding member part numbers 201072301 or 201072305. |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. For aircraft that are not compliant with the requirements of Netherlands CAA ADs 2002-060 and/or 2004-046 (AD/F100/53 Amdt 1), inspect the Main Landing Gear (MLG) sliding members for cracks in accordance with the Accomplishment Instructions of Messier-Dowty Service Bulletin (SB)F100-32-110 original issue, or later UK CAA approved revision;2. For all other aircraft, inspect the MLG sliding members for cracks in accordance with the Accomplishment Instructions of Messier-Dowty SB F100-32-110 original issue, or later UK CAA approved revision.Note 1: Fokker Service Bulletin SBF100-32-144 pertains to this subject.3. After compliance with either Requirement 1 or 2 of this Directive, repeat the inspection of the MLG sliding members in accordance with the Accomplishment Instructions of Messier-Dowty SB F100-32-110 original issue, or later UK CAA approved revision.4. Each time after a High Drag Load landing, magnetically inspect the MLG sliding members for cracks in accordance with Fokker 70/100 Aircraft Maintenance Manual (AMM), Task 05-51-01-220-826-A.5. Each time the aircraft brakes have been applied during backward movement of the aircraft, inspect the MLG sliding members in accordance with Fokker 70/100 AMM, Task 05-51-01-220-876-A.Note 2: Fokker Manual Change Notification - Maintenance Documentation (MCNM) F100-083 Rev.1 contains the procedures related to Requirements 4 and 5.When any crack indication is found, before further flight, replace the affected MLG sliding member with a serviceable part in accordance with Fokker 70/100 AMM, Chapter 32-11-08. |\n\n| | Whatever the results of the inspections as required by this Directive, report all findings to the Type Certificate Holder of the aircraft and the MLG manufacturer.Note 3: CAA-NL AD NL-2005-012 refers. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. Before the next flight after 19 January 2006.2. Within 2,000 flight cycles after the accomplishment of Messier-Dowty SB F100-32-103 (Ref. Fokker SBF100-32-133) or Messier-Dowty SB F100-32-105 (Ref. Fokker SBF100-32-139), or within the next 4 calendar months, whichever occurs later after 19 January 2006.3. At intervals not to exceed 2,000 flight cycles.4. Before further flight.5. Within the next 50 flight cycles thereafter. |\n| | This Amendment becomes effective on 19 January 2006. |\n| Background: | A failure of the sliding member of a main landing gear occurred during a terminal departure push-back, following inadvertent brake application. Investigation of the fractured surface revealed overload, initiated by a fatigue crack. Inspection of other aircraft revealed cracking in the same area.Amendment 1 required a second one-time inspection in response to the results of the previous inspection required by this Directive; in order to establish fleet safety.Amendment 2 is issued in response to a new CAA-NL AD, which was prompted by the results of further inspections that have identified the need for a repetitive inspection on the MLG Sliding Member to establish fleet safety. For this reason, this Directive requires repetitive magnetic particle inspections of all aircraft equipped with Dowty/Messier-Dowty Main Landing Gear units and replacement of cracked parts. |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n28 November 2005","sortOrder":0},{"sectionNumber":"AD/F100/53 Amdt 2","sectionType":"part","heading":"AD/F100/53 Amdt 2","content":"## AD/F100/53 Amdt 2","sortOrder":1},{"sectionNumber":"Main Landing Gear Sliding Member","sectionType":"part","heading":"Main Landing Gear Sliding Member","content":"## Main Landing Gear Sliding Member","sortOrder":2},{"sectionNumber":"1/2006","sectionType":"part","heading":"1/2006","content":"## 1/2006","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is Amendment 2 to an existing Airworthiness Directive. The scope remains focused on the original safety issue (main landing gear sliding member cracking) but has evolved to require repetitive inspections rather than one-time checks. This is a natural progression based on fleet inspection findings rather than scope creep — the directive still addresses the same specific mechanical failure mode on the same aircraft type."},"complexity_factors":["Multiple compliance pathways depending on prior maintenance history (Requirement 1 vs Requirement 2)","Five distinct inspection requirements with different triggers and intervals","Cross-references to external documents: Netherlands CAA ADs, UK CAA approved revisions, Messier-Dowty Service Bulletins, Fokker Service Bulletins, and Fokker Aircraft Maintenance Manual tasks","Specific part number applicability requiring verification against aircraft records (6 MLG part numbers, 2 sliding member part numbers)","Conditional logic: different compliance times based on whether previous service bulletins were accomplished","Nested references (e.g., Note 2 references MCNM F100-083 Rev.1 which contains procedures for Requirements 4 and 5)","Dual regulatory framework: references both Australian and foreign (Dutch/UK) aviation regulations"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific maintenance actions on certain aircraft.\n\n**What it does:**\nThis directive orders airlines and aircraft operators to inspect the **main landing gear sliding members** (a critical structural component that helps the landing gear extend and retract) on **Fokker F100 aircraft** for cracks. If cracks are found, the part must be replaced before the aircraft can fly again.\n\n**Who it affects:**\n- All Fokker F100 aircraft (also designated F.28 Mk. 0100 and Mk. 070)\n- Specifically those equipped with certain Dowty or Messier-Dowty main landing gear units (part numbers starting with 201072)\n- Aircraft operators, maintenance crews, and owners of these planes\n\n**What must be done:**\n- **Initial inspection:** Check for cracks using magnetic particle inspection methods, following specific technical instructions from the manufacturer (Messier-Dowty Service Bulletin F100-32-110)\n- **Repetitive inspections:** After the first check, re-inspect every 2,000 flight cycles (roughly takeoff-landing cycles)\n- **Special checks:** \n - After any \"high drag load\" landing (hard or rough landing)\n - Within 50 flight cycles if brakes were applied while the plane was moving backward (like during pushback from a gate)\n- **Reporting:** All findings must be reported to the aircraft manufacturer and the landing gear maker\n- **Replacement:** Any cracked parts must be replaced immediately before further flight\n\n**Why it matters:**\nThis directive was issued after a **main landing gear actually broke** during a routine pushback at an airport when brakes were accidentally applied. Investigation showed the failure started as a small fatigue crack that grew over time. Without these inspections, undetected cracks could cause the landing gear to collapse during takeoff, landing, or taxiing — potentially causing a serious accident.\n\n**Compliance deadlines:**\n- First inspection required before the next flight after 19 January 2006, or within specific timeframes based on previous maintenance history\n- Ongoing inspections required every 2,000 flight cycles thereafter"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This Amendment (Amdt 2) expands the Directive's scope compared with earlier iterations. The original action required one‑time inspections (and a second one‑time inspection under Amendment 1). Amendment 2 introduces mandatory repetitive magnetic particle inspections at intervals (not to exceed 2,000 flight cycles) for all affected aircraft, adds event‑triggered inspections (after High Drag Load landings and after brakes applied during backward movement), and formalises reporting and replacement-before-flight requirements. In short, the measure moves from initial/one‑time checks to an ongoing inspection and reporting regime covering the entire affected fleet (see Background; Requirements; Compliance)."},"complexity_factors":["Multiple applicability lines: two F28 Mk variants plus six MLG part numbers and two sliding member part numbers","Conditional requirements depending on prior compliance with Netherlands CAA ADs 2002‑060 and/or 2004‑046 (Requirement 1 vs 2)","Cross‑references to multiple documents (Messier‑Dowty SB F100‑32‑110, Fokker SBF100 SBs, Fokker 70/100 AMM tasks, CAA‑NL AD NL‑2005‑012)","Mixed inspection regimes: one‑time, repetitive (≤2,000 flight cycles), and event‑triggered inspections (High Drag Load landing; brakes applied during backward movement)","Multiple compliance timing rules with a ‘whichever occurs later’ clause (e.g. within 2,000 flight cycles after certain SBs or within 4 calendar months)","Different inspection methods referenced (general SB instructions vs magnetic particle inspection via AMM), requiring different skills/equipment","Mandatory immediate action on finding cracks (replace before further flight) and mandatory reporting obligations","Notes and references to other service bulletins and manual change notifications increasing traceability requirements"],"plain_english_summary":"This AD applies to Fokker F100 airplanes with certain Dowty/Messier‑Dowty main landing‑gear sliding members and mandates magnetic inspections (initial, repeating at ≤2,000 flight cycles and after specified events) per the Messier‑Dowty service bulletin and Fokker AMM. Any cracked sliding member must be replaced before further flight and all findings reported to Fokker and the MLG manufacturer.\n\nIt affects operators (who bear costs and schedule the work) and aims to detect fatigue cracks to prevent in‑service landing‑gear failures, at the expense of increased maintenance and downtime."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-53-amdt-2-main-landing-gear-sliding-member","history":"/api/acts/ad-f100-53-amdt-2-main-landing-gear-sliding-member/history","analysis":"/api/acts/ad-f100-53-amdt-2-main-landing-gear-sliding-member/analysis","conflicts":"/api/acts/ad-f100-53-amdt-2-main-landing-gear-sliding-member/conflicts","importantCases":"/api/acts/ad-f100-53-amdt-2-main-landing-gear-sliding-member/important-cases","documents":"/api/acts/ad-f100-53-amdt-2-main-landing-gear-sliding-member/documents"}}