{"id":"F2006B09613","name":"AD/F100/13 - Rear Spar-to-Fuselage Attachment","slug":"ad-f100-13-rear-spar-to-fuselage-attachment","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54369,"registerId":"commonwealth-F2006B09613-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F100/13 - Rear Spar-to-Fuselage Attachment","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/F100/13 Rear Spar-to-Fuselage Attachment 4/99\n\nApplicability: F.28 Mk.0100 aircraft, serial numbers, 11244 through 11319, 11321, and 11323\n\nthrough 11332.\n\nRequirement: Reinforce the rear spar-to-fuselage attachment and cold-sleeve expand the rear spar end fitting fastener holes in accordance with Fokker Service Bulletin (SB) F100-53- 039 dated 10 February 1993.\n\nNote: RLD BLA 93-027(A) refers.\n\nCompliance: Unless previously accomplished, before accumulating 24,000 flight cycles since new.\n\nThis Airworthiness Directive becomes effective on 22 April 1999.\n\nBackground: During fatigue tests on the F.28 Mk.0100, cracks were found in the coupling plate and the web plate of the rear spar end fitting at the attachment to the frame at fuselage STA.17011. Further investigation revealed additional cracks around the fastener holes in the rear spar end fitting.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive is narrowly targeted and prescriptive: it requires a specific structural modification for a defined set of aircraft serial numbers in response to cracks found during fatigue testing (Background; Applicability; Requirement). The scope as written confines the obligation to those aircraft and to the specific reinforcement and cold-sleeving procedure referenced in the Fokker service bulletin, so there is no indication in the text that the scope departs from that corrective purpose."},"complexity_factors":["Narrow applicability: specific aircraft model and a small range of serial numbers (Applicability)","Single, discrete technical requirement (reinforce attachment and cold-sleeve expand fastener holes) but requiring adherence to an external technical document (Fokker SB F100-53-039) (Requirement)","Compliance tied to an operational metric (24,000 flight cycles) which requires lifecycle tracking and planning (Compliance)","Work is structural and safety-critical, so it requires qualified maintenance facilities and personnel (Requirement)","Reference to additional documents (RLD BLA 93-027(A)) that may contain pertinent technical or compliance detail (Note)"],"plain_english_summary":"This rule mandates a structural modification — reinforcing the rear spar‑to‑fuselage attachment and cold‑sleeve expanding the rear spar end‑fitting fastener holes per Fokker Service Bulletin F100‑53‑039 — for specific Fokker F100 (F28 Mk 100) serial numbers.\n\nIt applies only to those listed aircraft, must be done before 24,000 flight cycles, was issued after fatigue tests found cracking, and requires affected operators to arrange and fund the work, with associated downtime and maintenance planning."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive (AD) issued under Part 39 of the Civil Aviation Regulations 1988. It maintains the original scope of aviation safety regulation - addressing a specific airworthiness concern through mandatory maintenance action. The document reflects the intended narrow, technical scope of ADs."},"complexity_factors":["Single, specific technical requirement with clear reference to manufacturer service bulletin","Only 4 defined applicability criteria (aircraft model and serial number ranges)","No nested exceptions or conditional logic - straightforward compliance deadline","Single compliance trigger (24,000 flight cycles) with one exemption (previously accomplished)","No cross-references to other legislation beyond a single note referencing a Dutch aviation authority document","Short document (approximately 150 words) with standard AD format"],"plain_english_summary":"This is a **safety order for specific Fokker F100 aircraft**.\n\n**What it does:**\nThe Civil Aviation Safety Authority (CASA) is ordering owners and operators of certain Fokker F100 planes to **reinforce a critical structural connection** between the rear wing spar (a major structural beam in the wing) and the fuselage (the main body of the aircraft). They must also **cold-sleeve expand** (a technique that strengthens metal by compressing it) the fastener holes in that area.\n\n**Who it affects:**\n- **Aircraft owners/operators** of Fokker F100 planes with serial numbers 11244 through 11319, 11321, and 11323 through 11332\n- **Maintenance organisations** responsible for keeping these aircraft airworthy\n\n**Why it matters:**\nFatigue testing (simulating years of takeoffs, landings, and pressurisation cycles) revealed **cracks in a critical structural joint**. This is serious because:\n- The rear spar-to-fuselage attachment helps hold the wing to the body of the plane\n- Cracks here could lead to **structural failure** if not addressed\n- The directive prevents potential accidents by mandating repairs **before 24,000 flight cycles** (roughly takeoff-landing cycles)\n\n**Key deadline:**\nThe work must be done before the aircraft reaches 24,000 flight cycles, unless already completed."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f100-13-rear-spar-to-fuselage-attachment","history":"/api/acts/ad-f100-13-rear-spar-to-fuselage-attachment/history","analysis":"/api/acts/ad-f100-13-rear-spar-to-fuselage-attachment/analysis","conflicts":"/api/acts/ad-f100-13-rear-spar-to-fuselage-attachment/conflicts","importantCases":"/api/acts/ad-f100-13-rear-spar-to-fuselage-attachment/important-cases","documents":"/api/acts/ad-f100-13-rear-spar-to-fuselage-attachment/documents"}}