{"id":"F2006B09686","name":"AD/F27/118 - Forward Fuselage Skin Joint","slug":"ad-f27-118-forward-fuselage-skin-joint","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115834,"registerId":"commonwealth-F2006B09686-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F27/118 - Forward Fuselage Skin Joint","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 F27 Series Aeroplanes\n\nAD/F27/118 Forward Fuselage Skin Joint 6/89 DM\n\nApplicability: All models with S/Nos 10102, 10105 through 10684, 10686, 10687, and 10689\n\nthrough 10692.\n\nRequirement: Inspect for fatigue cracks in the forward fuselage skin joints in accordance with Fokker Service Bulletin F27/53-108.\n\nNote: RLD BLA 89-020 refers.\n\nCompliance: Only aircraft that have flown more than a certain number of flights as at 10 April 1989 need to be inspected. This threshold number of flights is dependent upon the maximum cabin pressure differential for the aircraft. The threshold is 30,000 flights if the aircraft may have at any time operated at a cabin pressure differential of 5.5 psi, and 50,000 flights if the aircraft has always operated at a maximum cabin pressure differential of 4.16 psi. The compliance date for inspection is not later than 1 June 1989.\n\nBackground: Fatigue test results and an in-service failure indicate that multiple site fatigue cracking can occur in the forward fuselage skin joints. The manufacturer is initially asking for a one time visual inspection of high time aircraft to determine the need for repetitive inspections. It is therefore important that all inspection results be forwarded to the Authority and to the manufacturer.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with narrow applicability. It has not expanded beyond its original purpose of addressing a specific fatigue cracking issue in Fokker F27 fuselage joints."},"complexity_factors":["Limited conditional logic: two-tier flight threshold based on cabin pressure differential (30,000 vs 50,000 flights)","Specific serial number applicability list requiring cross-referencing","Single cross-reference to manufacturer service bulletin (F27/53-108) and related airworthiness directive (RLD BLA 89-020)","Temporal compliance deadline (1 June 1989) with retrospective trigger date (10 April 1989)","No defined terms section; straightforward technical vocabulary","Short document (approximately 200 words) with single operational requirement"],"plain_english_summary":"This CASA Airworthiness Directive mandates a one-time inspection of forward fuselage skin joints for fatigue cracks on specified Fokker F27 aircraft (certain serial numbers). It targets high-time aircraft and sets flight-count thresholds tied to cabin pressure (30,000 flights if ever at 5.5 psi; 50,000 if always ≤4.16 psi).\n\nInspections must follow Fokker Service Bulletin F27/53-108, be completed by 1 June 1989, and results reported to CASA and Fokker."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"No change of scope is indicated in the instrument. The directive applies to the listed serial numbers and requires a one‑time inspection per the manufacturer's service bulletin, with applicability determined by flight-count thresholds as at 10 April 1989 and a 1 June 1989 completion date."},"complexity_factors":["Applicability limited to a specific set of serial numbers — operators must check S/N lists to determine if the AD applies (Applicability).","Compliance depends on historical flight counts and recorded maximum cabin pressure differential as at 10 April 1989 (Compliance) — requires verifying maintenance/flight logs.","Two different numeric thresholds (30,000 vs 50,000 flights) tied to cabin differential history increase record‑checking complexity (Compliance).","Inspection procedure is defined by a manufacturer's service bulletin (Fokker Service Bulletin F27/53-108) — compliance requires following that technical document (Requirement).","Hard deadline for completion (1 June 1989) creates a narrow implementation window for affected operators (Compliance).","Reporting obligation to both the Authority and the manufacturer increases administrative burden and centralises data collection (Background).","Technical task: detect multiple-site fatigue cracking by visual inspection — may require access, skilled inspectors and interpretation of findings (Background).","Reference note (RLD BLA 89-020) and cross-references to external documents add procedural dependency and potential for ambiguity (Note)."],"plain_english_summary":"Requires a one‑time visual inspection of the forward fuselage skin joints for fatigue cracks on specified Fokker F27 serial numbers, carried out under Fokker Service Bulletin F27/53‑108. Only aircraft exceeding a flight-count threshold as at 10 April 1989 must be inspected.\n\nThe threshold is 30,000 flights if the aircraft ever operated at a 5.5 psi cabin differential, and 50,000 if it always operated at 4.16 psi. Inspections must be completed by 1 June 1989 and results forwarded to CASA and the manufacturer."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f27-118-forward-fuselage-skin-joint","history":"/api/acts/ad-f27-118-forward-fuselage-skin-joint/history","analysis":"/api/acts/ad-f27-118-forward-fuselage-skin-joint/analysis","conflicts":"/api/acts/ad-f27-118-forward-fuselage-skin-joint/conflicts","importantCases":"/api/acts/ad-f27-118-forward-fuselage-skin-joint/important-cases","documents":"/api/acts/ad-f27-118-forward-fuselage-skin-joint/documents"}}