{"id":"F2006B09714","name":"AD/F27/147 - Fuselage Attachment Fittings","slug":"ad-f27-147-fuselage-attachment-fittings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115889,"registerId":"commonwealth-F2006B09714-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F27/147 - Fuselage Attachment 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 F27 Series Aeroplanes\n\nAD/F27/147 Fuselage Attachment Fittings 10/99\n\nApplicability: Model F27 Mk. 100 through Mk. 700 (except Mk. 500RF), serial numbers 10102 and 10105 through 10582.\n\nRequirement: Inspect the wing-to-fuselage fittings in accordance with the Accomplishment Instructions of STORK Fokker Service Bulletin F27/57-77.\n\nNote: RLD AD 1999-053 refers.\n\nCompliance: Before 7 December 1999, unless already accomplished.\n\nThis Airworthiness Directive becomes effective on 7 October 1999.\n\nBackground: The RLD received a report of a cracked wing-to-fuselage attachment fitting. An investigation revealed that the cracking had resulted from stress corrosion cracking. The subject fittings are manufactured from 7079-T6 aluminium, which is known to be sensitive to this type of corrosion.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The supplied directive does not indicate any change of scope from an earlier instrument. It defines a specific, limited scope: specified F27 models and serial numbers must undergo inspection per the referenced STORK Fokker Service Bulletin, by the stated deadline. No expansion or narrowing of that scope is signalled in the text provided (Applicability; Requirement; Compliance)."},"complexity_factors":["Narrow applicability tied to specific models and serial numbers (Applicability)","Single, time-limited mandatory action (inspection) with a defined compliance date (Requirement; Compliance)","Dependence on an external technical document (STORK Fokker Service Bulletin F27/57-77) for procedural detail (Requirement)","Technical cause referenced (stress corrosion cracking of 7079-T6 aluminium) but corrective actions not detailed in the AD text (Background; Requirement)","Regulatory provenance and effective date stated, but enforcement and cost allocation not specified in the excerpt (header; Compliance)"],"plain_english_summary":"What this changes, mechanically:\n\n- This Airworthiness Directive requires operators of certain Fokker F27 aeroplanes to inspect the wing-to-fuselage attachment fittings. The inspection must be carried out exactly as set out in the Accomplishment Instructions of STORK Fokker Service Bulletin F27/57-77 (Requirement). The directive sets a compliance deadline: the inspection must be done before 7 December 1999 unless already completed (Compliance). The directive took effect on 7 October 1999 (effective date).\n\nWho it applies to and who decides:\n\n- It applies to Fokker F27 models Mk. 100 through Mk. 700, except Mk. 500RF, and only to the listed serial numbers (10102 and 10105 through 10582) (Applicability). The Civil Aviation Safety Authority issued the directive under the Civil Aviation Regulations framework (header). The directive itself specifies the required action and the compliance date (Requirement; Compliance).\n\nWhy the inspection is required (official rationale and mechanical facts):\n\n- The background given is that an authority (RLD) received a report of a cracked wing-to-fuselage attachment fitting and an investigation identified stress corrosion cracking as the cause. The fittings concerned are made from 7079-T6 aluminium, which the directive notes is sensitive to stress corrosion cracking (Background). The directive therefore mandates inspection to detect cracking.\n\nPractical consequences, incentives and who pays:\n\n- Operators or owners of the affected aeroplanes bear the cost and operational impact of carrying out the inspections and any follow-on actions (Applicability; Requirement). The inspection must follow the named service bulletin, so compliance requires access to and use of that technical document (Requirement).\n\n- The regulator (Civil Aviation Safety Authority) sets the compliance date and enforces the directive; it does not, in the text provided, allocate funding or state who performs repairs if cracking is found (header; Requirement).\n\nCompliance burden and implementation points:\n\n- The AD prescribes an external technical standard (the STORK Fokker Service Bulletin F27/57-77) rather than listing inspection steps in the directive itself, so implementers must obtain and follow that bulletin to meet the AD (Requirement).\n\n- The directive establishes a fixed deadline (before 7 December 1999) for completing the inspection unless already done, creating a time-limited operational disruption risk (Compliance).\n\nDiscretion and gaps in the text provided:\n\n- The AD mandates inspection per the service bulletin but does not, in the text supplied, set out corrective actions or repair criteria within the directive itself; those details are likely in the referenced service bulletin or other maintenance documents (Requirement).\n\n- The AD does not allocate costs, compensation, or explicitly state enforcement mechanisms in the excerpt supplied. It also does not expand or narrow the list of affected serial numbers beyond those listed (Applicability).\n\nTrade-offs, risks and implementation considerations:\n\n- The stated safety trigger is stress corrosion cracking in fittings made of 7079-T6 aluminium (Background). If present, such cracking creates a technical need for inspection; not inspecting risks undetected cracking. The mechanical trade-offs for operators include inspection cost and aircraft downtime versus the risk of operating with potentially cracked fittings (Background; Compliance).\n\n- Because the directive references an external service bulletin for the inspection method, timely access to that bulletin and the capacity to carry out the specified inspections are practical prerequisites for compliance (Requirement)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating inspections for stress corrosion cracking in wing-to-fuselage fittings."},"complexity_factors":["Very short document (approximately 150 words)","Only 4 defined elements: specific aircraft models, serial number ranges, material specification (7079-T6 aluminium), and reference to external technical document","Single, unambiguous compliance requirement with clear deadline","No nested conditional logic or exceptions","One external cross-reference (to Dutch authority directive) for background only, not for operative requirements","Straightforward applicability criteria using model numbers and serial numbers"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a \"recall notice\" for aircraft, but with legal force. It requires specific inspections or repairs to keep planes airworthy.\n\n**What it does:** This AD orders owners and operators of certain Fokker F27 aircraft to inspect the **wing-to-fuselage attachment fittings** — the critical metal brackets that bolt the wings to the plane's body. The inspection must follow instructions in a specific technical bulletin (STORK Fokker Service Bulletin F27/57-77).\n\n**Why it matters:** A cracked wing attachment fitting is catastrophic — it could cause the wing to separate from the fuselage in flight. The cracking is caused by **stress corrosion cracking**, a chemical-mechanical failure that affects 7079-T6 aluminium alloy under tension. This material is known to be vulnerable to this problem.\n\n**Who it affects:** \n- **Aircraft:** Fokker F27 Mk. 100 through Mk. 700 models (excluding the Mk. 500RF variant), with serial numbers 10102 and 10105 through 10582.\n- **People:** Airlines, charter operators, and private owners flying these specific Fokker F27 aircraft.\n\n**When it had to be done:** Before 7 December 1999 (unless already completed). The AD took effect on 7 October 1999.\n\n**Key context:** This follows a report to the Dutch aviation authority (RLD — Rijksluchtvaartdienst) about an actual cracked fitting discovered on an aircraft. The AD references the Dutch authority's corresponding directive (RLD AD 1999-053), showing international coordination on this safety issue."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f27-147-fuselage-attachment-fittings","history":"/api/acts/ad-f27-147-fuselage-attachment-fittings/history","analysis":"/api/acts/ad-f27-147-fuselage-attachment-fittings/analysis","conflicts":"/api/acts/ad-f27-147-fuselage-attachment-fittings/conflicts","importantCases":"/api/acts/ad-f27-147-fuselage-attachment-fittings/important-cases","documents":"/api/acts/ad-f27-147-fuselage-attachment-fittings/documents"}}