{"id":"F2006L00696","name":"AD/F100/77 - Main Landing Gear Main Fitting - 4","slug":"ad-f100-77-main-landing-gear-main-fitting-4","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":136713,"registerId":"commonwealth-F2006L00696-current","compilationNumber":null,"startDate":"2026-04-03","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/F100/77 | Main Landing Gear Main Fitting - 4 | 4/2006 |\n| ---------- | ---------------------------------- | ------ |\n\n| Applicability: | Model F.28 Mk. 0070 and Mk. 0100 aircraft, all serial numbers, if equipped with Messier-Dowty (formerly Dowty Aerospace Gloucester) Main Landing Gears. |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. For all installed MLG Main Fitting units, except as indicated in Requirement 2 of this Directive, inspect and as necessary, rework the MLG Main Fitting in accordance with the Accomplishment Instructions of Messier-Dowty Service Bulletin (SB) F100-32-111, dated 20 December 2005, or later EASA approved revision.2. For new MLG Main Fitting units and MLG Main Fitting units on which both bores have been reworked as required by CAA-NL AD 2002-115/2 (AD/F100/55 Amdt 1) or NL-2005-002 (AD/F100/64), inspect and as necessary, rework the MLG Main Fitting in accordance with the Accomplishment Instructions of SB F100-32-111, or later EASA approved revision.3. Thereafter, inspect and as necessary, rework the MLG Main Fitting in accordance with the Accomplishment Instructions of SB F100-32-111, or later EASA approved revision.Whenever cracks are found, determine whether (and for how many) flights may be continued, before rework or replacement, in accordance with the crack size and location thresholds as listed in Fokker Services SBF100-32-146, dated2 February 2006, or later EASA approved revision.4. Whenever, following a crack finding (or for any other reason), a MLG Main Fitting has been reworked (both bores) or replaced by a new MLG Main Fitting, inspect and as necessary, rework the MLG Main Fitting in accordance with the Accomplishment Instructions of SB F100-32-111, or later EASA approved revision.5. No Dowty Aerospace Gloucester or Messier-Dowty MLG Main Fitting unit (except for new or reworked units, as indicated in Requirements 2 or 4 of this Directive) may be installed as a replacement part, unless it has been inspected, and as necessary, reworked in accordance with SB F100-32-106, dated18 February 2005 or SB F100-32-111; or later EASA approved revisions. |\n\n| | Irrespective of the results, within 7 calendar days after each inspection as required by Requirements 1, 2, 3, and 4 of this Directive, report all findings to Fokker Services using the questionnaire attached to Fokker ServicesSBF100-32-146.Note: CAA-NL AD NL-2006-003 refers. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. Within the next 2,000 flight cycles since the last inspection in accordance with Messier-Dowty SB F100-32-106 and Fokker Services SBF100-32-141, as required by AD NL-2005-002 (AD/F100/64), or within the next 4 months after 13 April 2006, whichever occurs later.2. Within 4,000 flight cycles since new (installation) or rework, as applicable.3. At intervals not to exceed 2,000 flight cycles.4. Within 4,000 flight cycles since new (installation) or rework, as applicable, and thereafter at intervals not to exceed 2,000 flight cycles.5. As of the effective date of this Directive. |\n| | This Airworthiness Directive becomes effective on 13 April 2006. |\n| Background: | Two cases have been reported of Fokker 100 aircraft, being moved backward for maintenance, suffering failure of a Main Landing Gear Main Fitting upon brake application. CAA-NL previously issued AD 2002-115/2 and NL-2005-002 to prevent and remedy this problem. Both ADs still apply and require one-time inspections, an AFM change and the introduction of a placard that prohibit application of the brakes during any backwards movement of the aircraft. This Directive requires the introduction of a repetitive inspection for cracks and rework, as necessary. |\n\n![](image.001.png) \nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n1 March 2006","sortOrder":0},{"sectionNumber":"AD/F100/77","sectionType":"part","heading":"AD/F100/77","content":"## AD/F100/77","sortOrder":1},{"sectionNumber":"Main Landing Gear Main Fitting - 4","sectionType":"part","heading":"Main Landing Gear Main Fitting - 4","content":"## Main Landing Gear Main Fitting - 4","sortOrder":2},{"sectionNumber":"4/2006","sectionType":"part","heading":"4/2006","content":"## 4/2006","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original scope as a targeted safety intervention for a specific mechanical failure mode in Fokker F100 aircraft. The document references previous related ADs but does not expand beyond the original purpose of addressing main landing gear main fitting failures. The repetitive inspection regime represents an evolution of the safety response based on continued risk assessment, not scope creep."},"complexity_factors":["Multiple cross-references to other Airworthiness Directives (AD/F100/55, AD/F100/64) and foreign regulator documents (CAA-NL AD 2002-115/2, NL-2005-002, NL-2006-003)","Five distinct requirement categories with different compliance timelines and technical procedures","Conditional logic: different inspection requirements based on whether units are 'new', 'reworked', or 'installed'","Reference to external technical documents (Service Bulletins F100-32-111, F100-32-106, and F100-32-146) that are not reproduced in the directive itself","Nested exceptions: Requirement 2 and Requirement 4 create carve-outs from Requirement 1 and general rules","Dual compliance triggers (flight cycles OR calendar time, whichever is later)","Specific reporting obligations with tight deadline (7 calendar days) and prescribed form"],"plain_english_summary":"This AD requires owners/operators of Fokker F100 (F.28 Mk.0070/0100) with Messier-Dowty main landing gear to inspect, rework/repair, and report on the main landing gear main fitting after reports of two complete failures when brakes were used during backward movement. It also bans installing fittings unless inspected/reworked per the service instructions.\n\nInitial inspection is due within 2,000 flight cycles or 4 months after 13 April 2006, with repeat inspections every 2,000 cycles and mandatory reporting of results to Fokker Services."},"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":true,"description":"This Directive expands scope from earlier, one‑time measures (previous CAA‑NL ADs requiring a one‑off inspection, AFM change and placard) to ongoing mandatory inspections and rework, a prohibition on installing uninspected/unreworked replacement fittings, and a formalised 7‑day reporting obligation. It shifts the regime from a one‑off operational restriction to a continuing maintenance and parts‑control obligation, increasing recurring compliance and maintenance costs for operators."},"complexity_factors":["Multiple, interdependent requirements: initial inspections, rework, repeat inspections and installation prohibitions (Requirements 1–5).","Cross-references to several external technical documents and prior ADs (Messier‑Dowty SB F100‑32‑111, SB F100‑32‑106; Fokker SBF100‑32‑146; CAA‑NL AD 2002‑115/2 and NL‑2005‑002).","Different compliance windows and intervals tied to flight cycles and calendar time (2,000 fc, 4,000 fc, within 4 months or 2,000 fc since last inspection).","Operational decision point: permitted number of continued flights after finding cracks must be determined per Fokker Services thresholds (affects dispatch/airworthiness decisions).","Reporting requirement within 7 calendar days after each inspection increases administrative burden and creates a data flow to the manufacturer.","Parts-control rule: prohibition on installing Dowty/Messier‑Dowty fittings unless inspected/reworked under specified SBs adds logistics and supply‑chain constraints.","Applicability is broad (all serial numbers fitted with Messier‑Dowty MLG), so many operators may be affected.","Technical work (bore rework, crack inspection) likely requires specialist maintenance capability and may cause aircraft downtime."],"plain_english_summary":"This Airworthiness Directive requires operators of Fokker F100 (F28 Mk 100) aircraft with Messier‑Dowty main landing gears to inspect and, if needed, rework or replace the main landing‑gear fitting to detect and fix cracks. It sets mandatory initial and recurring inspection intervals, a reporting obligation to Fokker Services, and bars installing uninspected/unreworked replacement fittings. Airlines and maintenance organisations pay for inspections, rework and downtime; the regulator sets timing and allows limited continued flights based on crack‑size thresholds."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-77-main-landing-gear-main-fitting-4","history":"/api/acts/ad-f100-77-main-landing-gear-main-fitting-4/history","analysis":"/api/acts/ad-f100-77-main-landing-gear-main-fitting-4/analysis","conflicts":"/api/acts/ad-f100-77-main-landing-gear-main-fitting-4/conflicts","importantCases":"/api/acts/ad-f100-77-main-landing-gear-main-fitting-4/important-cases","documents":"/api/acts/ad-f100-77-main-landing-gear-main-fitting-4/documents"}}