{"id":"F2006B09611","name":"AD/F100/11 - Rear Spar & MLG Bottom Joint Fittings","slug":"ad-f100-11-rear-spar-mlg-bottom-joint-fittings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54367,"registerId":"commonwealth-F2006B09611-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F100/11 - Rear Spar & MLG Bottom Joint Fittings","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/F100/11 Rear Spar & MLG Bottom Joint Fittings 4/99\n\nApplicability: F.28 Mk.0100 aircraft, serial numbers, 11244 through 11390.\n\nRequirement: Replace affected fittings and reinforce the MLG spar fittings, the rear spar webs and the new bottom joint fittings in accordance with Fokker Service Bulletin (SB) F100- 57-020 dated 27 April 1992.\n\nNote: RLD BLA 92-075 refers.\n\nCompliance: Unless previously accomplished, before accumulating 13,500 flight cycles since new.\n\nThis Airworthiness Directive becomes effective on 22 April 1999.\n\nBackground: During fatigue testing of the F.28 Mk.0100, cracks were found in the main landing gear spar fitting at wing STA.2800 and in the rear spar web at STA.2900. This condition, if not corrected, will result in loss of structural integrity of the aircraft in the affected areas. This AD requires the replacement of the affected fittings and subsequent reinforcement.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive addressing a specific structural defect identified during fatigue testing. It has not expanded beyond its original purpose of mandating repairs to prevent cracks in the rear spar and main landing gear bottom joint fittings."},"complexity_factors":["Very short document (approximately 150 words)","Only 3 defined technical terms (STA.2800, STA.2900, flight cycles) with contextual explanations provided","Single unconditional requirement with one straightforward exception ('Unless previously accomplished')","No cross-references to other legislation or regulations beyond a single reference to a Fokker Service Bulletin and a related Dutch aviation authority document (RLD BLA 92-075)","Clear, linear structure: applicability → requirement → compliance deadline → background","No nested conditions, exceptions, or discretionary provisions"],"plain_english_summary":"This is a **safety order for specific Fokker F100 aircraft**.\n\n**What it does:**\nThis Airworthiness Directive (AD) — essentially a mandatory safety fix — requires owners or operators of certain Fokker F100 aeroplanes to replace and reinforce specific structural parts in the wing where the main landing gear attaches.\n\n**Who it affects:**\n- **Aircraft owners/operators** of Fokker F.28 Mk.0100 planes with serial numbers 11244 through 11390\n- **Maintenance crews** who must carry out the physical work\n\n**The problem:**\nFatigue testing (repeated stress testing) revealed cracks in two critical areas:\n- The main landing gear spar fitting at a specific wing location (STA.2800)\n- The rear spar web at another location (STA.2900)\n\nIf left unfixed, these cracks could cause **structural failure** in these areas.\n\n**What must be done:**\n- Replace the cracked/damaged fittings\n- Reinforce the main landing gear spar fittings, rear spar webs, and new bottom joint fittings\n- Follow the exact instructions in **Fokker Service Bulletin F100-57-020** (dated 27 April 1992)\n\n**When it must be done:**\nBefore the aircraft reaches **13,500 flight cycles** (roughly, one takeoff and landing) since it was built — unless the work was already done.\n\n**Why it matters:**\nThis prevents potential catastrophic structural failure. The directive became enforceable on 22 April 1999."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive implements the corrective work described in the background (replacement and reinforcement to address fatigue cracks). The scope—targeting F.28 Mk.0100 serial numbers 11244–11390 and requiring work before 13,500 flight cycles—matches the mechanical remedy and safety reason set out in the Background and Requirement sections; there is no indication in the source text that the scope departs from that stated intent."},"complexity_factors":["Narrow applicability limited to specific aircraft model and serial-number range (Applicability)","Mandated work must follow a specified Fokker Service Bulletin (technical dependency) (Requirement)","Clear compliance threshold tied to flight cycles (13,500 flight cycles) (Compliance)","Fixed effective date for regulatory obligation (22 April 1999)","Operational impacts: parts availability, labour competence and aircraft downtime affect implementation"],"plain_english_summary":"The Airworthiness Directive requires replacement and reinforcement of specific main landing gear and rear spar fittings on Fokker F.28 Mk.0100 aircraft (serials 11244–11390) per Fokker Service Bulletin F100-57-020, to be completed before each affected airplane reaches 13,500 flight cycles. \n\nOrdered after fatigue testing found cracks that threaten structural integrity, the AD (effective 22 April 1999) shifts compliance costs and scheduling to aircraft owners/operators and creates near‑term demand for qualified maintenance and parts suppliers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-11-rear-spar-mlg-bottom-joint-fittings","history":"/api/acts/ad-f100-11-rear-spar-mlg-bottom-joint-fittings/history","analysis":"/api/acts/ad-f100-11-rear-spar-mlg-bottom-joint-fittings/analysis","conflicts":"/api/acts/ad-f100-11-rear-spar-mlg-bottom-joint-fittings/conflicts","importantCases":"/api/acts/ad-f100-11-rear-spar-mlg-bottom-joint-fittings/important-cases","documents":"/api/acts/ad-f100-11-rear-spar-mlg-bottom-joint-fittings/documents"}}