{"id":"F2008L01936","name":"AD/F100/73 Amdt 1 - Wing-to-Fuselage Fairings","slug":"ad-f100-73-amdt-1-wing-to-fuselage-fairings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74169,"registerId":"commonwealth-F2008L01936-current","compilationNumber":null,"startDate":"2026-04-02","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/F100/73 Amdt 1 | Wing-to-Fuselage Fairings | 7/2008 |\n| ----------------- | ------------------------- | ------ |\n\n| Applicability: | Model F.28 Mk. 0100 and Mk. 0070 aircraft, all serial numbers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Inspect the aerodynamic seal of the wing-to-fuselage fairings and the fuselage skin, and apply an improved sealing by means of a fillet seal in accordance with the Accomplishment Instructions of Fokker Services SBF100-53-107, dated26 February 2008, or later EASA approved revision.Note: EASA AD 2008-0079 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| Compliance:    | Within 12 calendar months after 3 July 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n|                | This Amendment becomes effective on 3 July 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| Background:    | Reports were received from Fokker 100 operators of flight crews experiencing in- flight difficulties with roll control. Investigation revealed that roll control difficulties were due to ice on the aileron pulleys that are installed on the centre wing spar and located in the main landing gear wheel bays. The actions required by this Directive were intended to prevent rainwater, wash-water, or de-icing fluid leaking onto the affected aileron pulleys.Amendment 1 is issued in response to a new EASA AD, which was prompted by new reports of problems due to moisture in the same affected area. This AD mandates a new service bulletin from Fokker Services which requires an additional one-time inspection and application of improved sealing. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n16 May 2008","sortOrder":0},{"sectionNumber":"AD/F100/73 Amdt 1","sectionType":"part","heading":"AD/F100/73 Amdt 1","content":"## AD/F100/73 Amdt 1","sortOrder":1},{"sectionNumber":"Wing-to-Fuselage Fairings","sectionType":"part","heading":"Wing-to-Fuselage Fairings","content":"## Wing-to-Fuselage Fairings","sortOrder":2},{"sectionNumber":"7/2008","sectionType":"part","heading":"7/2008","content":"## 7/2008","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This Amendment expands the previous directive by mandating an additional one‑time inspection and the application of an improved fillet seal, prompted by new reports of moisture problems in the same area. Mechanically, the scope broadened from the original action (preventing leakage of rain/wash/de‑icing fluid) to include the new service bulletin requirements specified in response to EASA AD 2008‑0079. The change increases the set of required actions (inspection + sealing per the updated service bulletin) though it remains limited to the same affected structural area and fleet."},"complexity_factors":["Single clear applicability: two model designations (F.28 Mk.0100 and Mk.0070), all serial numbers","One primary required action: inspect wing-to-fuselage fairing seal and apply a fillet seal","Reference to a single service bulletin (Fokker SBF100-53-107 dated 26 Feb 2008) with allowance for later EASA‑approved revisions","One compliance timeframe: within 12 calendar months after 3 July 2008","Cross-reference to EASA AD 2008-0079 and dependence on EASA approval for later revisions","Amendment-driven change (adds a one-time inspection and improved sealing in response to new reports) but no ongoing monitoring/recurring tasks","Limited conditional logic and no nested exceptions or multiple alternative compliance pathways"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Requires owners/operators of Fokker F100 (F28 Mk 100 and Mk 0070) aeroplanes (all serial numbers) to inspect the aerodynamic seal where the wing fairings meet the fuselage and to apply an improved fillet seal to that joint.  \n- The work must be done in accordance with Fokker Services Service Bulletin SBF100-53-107 dated 26 February 2008, or a later revision that has been approved by EASA (the European aviation safety regulator).  \n- The mandated work is a one-time action, to be completed within 12 calendar months after 3 July 2008 (i.e. by 3 July 2009).  \n\n**Why the rule was made (official rationale)\n\n- The AD states that flight crews reported in‑flight roll control difficulties. Investigations linked those difficulties to ice forming on aileron pulleys located on the centre wing spar within the main landing gear wheel bays.  \n- The required sealing is intended to prevent rainwater, wash-water or de‑icing fluids from leaking into that area and contaminating or icing the aileron pulley assemblies.  \n- This Amendment (Amdt 1) follows a new EASA AD prompted by additional reports of moisture problems in the same area and therefore mandates an updated Fokker service bulletin requiring a further one‑time inspection and improved sealing.\n\n**Who is affected and who pays\n\n- Affected: every operator and owner of the listed Fokker F100 models (all serial numbers).  \n- Pays: the aircraft owners/operators pay for inspection labour, materials and any access/maintenance time required to apply the fillet seal and record the work.\n\n**What decisions are controlled by regulators\n\n- The Civil Aviation Safety Authority (via this AD) mandates the inspection and sealing and specifies the Fokker service bulletin as the required method.  \n- The AD allows later revisions of that service bulletin only if those revisions are approved by EASA; this gives EASA control over acceptable changes to the required procedure.\n\n**Compliance mechanics and record keeping\n\n- Work must follow the Accomplishment Instructions in the cited Fokker service bulletin (or an EASA‑approved later revision).  \n- The AD is a mandatory regulatory requirement for the affected aircraft; operators must complete the work within the specified 12‑month window and retain maintenance records demonstrating compliance.\n\n**Costs, incentives, trade‑offs and implementation risks (practical assessment)\n\n- Direct costs: a single inspection and sealing procedure — labour, parts (fillet seal material) and aircraft downtime. The one‑time nature limits recurring costs.  \n- Operational impact: aircraft will need maintenance access to the wing‑to‑fuselage fairing area; this can require removal of panels and short grounding for the work.  \n- Incentives: operators gain reduced risk of moisture ingress and associated aileron control problems; they also face enforcement risk (regulator can require proof of compliance).  \n- Bureaucratic discretion: the AD ties acceptable procedures to a specific Fokker service bulletin and to EASA approval of later revisions; this centralises technical judgement with the manufacturer and EASA rather than leaving it to individual operators.  \n- Implementation risk: effectiveness depends on following the approved instructions; operators using non‑approved methods risk non‑compliance.  \n\n**Concentrated benefits and diffuse costs\n\n- Benefits (concentrated): improved protection for the aileron pulley assemblies and mitigation of the particular safety hazard for aircraft that experience moisture ingress.  \n- Costs (diffuse across operators): time and expense to perform a one‑off inspection/seal across the whole in‑service fleet.  \n\nNotes on references in the AD\n\n- The AD explicitly references Fokker Services SBF100-53-107 (26 Feb 2008) and EASA AD 2008‑0079 as the regulatory and technical sources for the mandated work. These references create reliance on the service bulletin content and on EASA for approval of any later procedural changes."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of addressing moisture ingress in the wing-to-fuselage area of Fokker F100 aircraft. While it adds an additional inspection requirement and improved sealing method in response to new reports, this represents a refinement of the original safety purpose rather than an expansion beyond it. The directive remains tightly focused on the specific technical issue of preventing moisture from reaching aileron pulleys."},"complexity_factors":["Single, specific technical requirement with clear reference to external technical document (Fokker Services SBF100-53-107)","Only one defined term implicitly used (EASA - European Union Aviation Safety Agency)","No nested conditional logic or exceptions","Straightforward applicability criteria (two specific aircraft models, all serial numbers)","Single compliance deadline with no alternative methods or phased implementation","Short document with minimal cross-referencing (only references one EASA AD and one service bulletin)"],"plain_english_summary":"This CASA Airworthiness Directive (Amendment 1) mandates inspection and upgrade of the aerodynamic fillet seal at the wing-to-fuselage fairings on all Fokker F100 aircraft to stop water, de-icing or wash fluid leaking into wheel bays and freezing on aileron pulleys — a condition that has impaired roll control. It updates an earlier AD after further reports and requires compliance within 12 months of 3 July 2008."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-73-amdt-1-wing-to-fuselage-fairings","history":"/api/acts/ad-f100-73-amdt-1-wing-to-fuselage-fairings/history","analysis":"/api/acts/ad-f100-73-amdt-1-wing-to-fuselage-fairings/analysis","conflicts":"/api/acts/ad-f100-73-amdt-1-wing-to-fuselage-fairings/conflicts","importantCases":"/api/acts/ad-f100-73-amdt-1-wing-to-fuselage-fairings/important-cases","documents":"/api/acts/ad-f100-73-amdt-1-wing-to-fuselage-fairings/documents"}}