{"id":"F2005L01370","name":"AD/F28/89 - APU Enclosure Drains and Wiring","slug":"ad-f28-89-apu-enclosure-drains-and-wiring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":35198,"registerId":"commonwealth-F2005L01370-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Fokker F28 Series Aeroplanes","sectionType":"division","heading":"Fokker F28 Series Aeroplanes","content":"### Fokker F28 Series Aeroplanes\n\n| AD/F28/89 | APU Enclosure Drains and Wiring | 7/2005 |\n| --------- | ------------------------------- | ------ |\n\n| Applicability: | Fokker Aircraft Model F.28 Mk.1000 through 4000 series.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Perform a one-time inspection on the drain tubes and the wiring underneath the APU enclosure in accordance with the Accomplishment Instructions of Fokker Service Bulletin (SB) F28/49-038, dated 26 April 2004 or later CAA-NL / EASA approved revisions.Note: BLA (CAA - The Netherlands) Airworthiness Directive (AD) 2004-059 dated 29 April 2004, approved under EASA reference 2004-4045 dated 20 April 2004 refers.                                                                                                                                                                                                                                                                                |\n| Compliance:    | Unless already accomplished, within the next 6 calendar months after the effective date of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n|                | This Airworthiness Directive becomes effective on 7 July 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| Background:    | Following an APU fire incident, inspection of the aircraft revealed that the fire had caused severe damage to the rear pressure bulkhead as well as the wiring and flight control cables that run between the APU enclosure and the rear pressure bulkhead. Subsequent investigation showed that one of the APU drains was not connected to the APU enclosure feed-through, allowing fuel to accumulate underneath the APU enclosure.Accumulated fuel in or under the APU enclosure may lead to fire and / or loss of aircraft. The AD addresses the identified unsafe condition through a one-time inspection to verify that all drain tubes are correctly installed and that the wiring is not damaged. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n23 May 2005","sortOrder":0},{"sectionNumber":"AD/F28/89","sectionType":"part","heading":"AD/F28/89","content":"## AD/F28/89","sortOrder":1},{"sectionNumber":"APU Enclosure Drains and Wiring","sectionType":"part","heading":"APU Enclosure Drains and Wiring","content":"## APU Enclosure Drains and Wiring","sortOrder":2},{"sectionNumber":"7/2005","sectionType":"part","heading":"7/2005","content":"## 7/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The Directive stays within the original safety-focused purpose: to eliminate the unsafe condition caused by fuel accumulation under the APU enclosure (as described in the Background) by mandating an inspection to confirm drain tubes are correctly installed and wiring is undamaged (Requirement). It does not expand into additional or unrelated regulatory areas, nor does it impose recurring obligations beyond the one-time inspection."},"complexity_factors":["Single substantive action: one-time inspection","Limited applicability: F28 Mk.1000–4000 series only","Short compliance window: 6 calendar months","Cross-reference to an external document: Fokker Service Bulletin F28/49-038 (26 Apr 2004) or later CAA-NL/EASA approved revisions","Dependence on foreign authority approvals (CAA–Netherlands / EASA)","No layered exceptions, appeals, or recurring actions specified","No lengthy definitions or nested conditional provisions in the text provided"],"plain_english_summary":"The rule mandates a one‑time inspection of APU enclosure drains and wiring on Fokker F.28 Mk.1000–4000 series, to be done within six months following Fokker Service Bulletin F28/49‑038 (or an approved revision). It aims to detect misconnected drains or wiring damage after an APU‑fire incident that caused fuel accumulation and structural/control damage.\n\nOperators bear inspection and repair costs and must ground affected aircraft as needed to complete remedial work."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive issued in response to a specific incident. It addresses exactly one unsafe condition (APU drain tube installation and wiring damage) with a single mandated action. There is no evidence of scope creep; the document remains tightly focused on its original safety purpose."},"complexity_factors":["Single, discrete requirement (one inspection)","No defined terms section or interpretation provisions","Minimal conditional logic (only 'unless already accomplished' exception)","Single cross-reference to Fokker Service Bulletin and Dutch/EASA AD for technical details","Short document (approximately 200 words of substantive content)","Clear, linear structure: applicability → requirement → compliance → background"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to **Fokker F28 aircraft** (models Mk.1000 through 4000).\n\n**What it requires:**\n- Aircraft operators must perform a **one-time inspection** of:\n  - Drain tubes underneath the Auxiliary Power Unit (APU) enclosure — basically, the pipes that should carry fluids away from a small engine at the back of the plane\n  - Wiring running in the same area\n\n**Why it matters:**\n- An APU fire on one aircraft revealed that a drain tube wasn't properly connected, allowing **fuel to pool underneath the enclosure**\n- This created a fire risk that could damage critical flight controls and the rear pressure bulkhead (a major structural wall at the back of the passenger cabin)\n- The inspection ensures drain tubes are correctly installed and wiring isn't damaged\n\n**When to comply:**\n- Within **6 months** of 7 July 2005 (unless already done)\n\n**The bottom line:** This is a reactive safety fix — after a fire revealed a dangerous design/maintenance issue, regulators ordered all similar aircraft checked to prevent it happening again."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f28-89-apu-enclosure-drains-and-wiring","history":"/api/acts/ad-f28-89-apu-enclosure-drains-and-wiring/history","analysis":"/api/acts/ad-f28-89-apu-enclosure-drains-and-wiring/analysis","conflicts":"/api/acts/ad-f28-89-apu-enclosure-drains-and-wiring/conflicts","importantCases":"/api/acts/ad-f28-89-apu-enclosure-drains-and-wiring/important-cases","documents":"/api/acts/ad-f28-89-apu-enclosure-drains-and-wiring/documents"}}