{"id":"F2006B03483","name":"AD/BAe 146/31 - Nose Cowl Extinguisher Pipe","slug":"ad-bae-146-31-nose-cowl-extinguisher-pipe","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43037,"registerId":"commonwealth-F2006B03483-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/31 - Nose Cowl Extinguisher Pipe","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  British Aerospace BAe 146 Series Aeroplanes\n\n \n\nAD/BAe 146/31 Nose Cowl Extinguisher Pipe 4/91\n\nApplicability:   Model 146:\n\n \n\nAll Series 100 and 100A aircraft upto and including E1152. All Series 200 and 200A aircraft upto and including E2156. All Series 300 and 300A aircraft upto and including E3157.\n\nRequirement:   Action in accordance with mandatory BAe 146 SB 26-A29 Revision 2.\n\n \n\nNote: Operators who have already complied with SB 26-A29 will not be required to carry out any additional inspections as a result of this revision.\n\n \n\nCompliance:   Prior to 31 May 1991.\n\n \n\nBackground: A case has been reported of an extinguisher pipe in the nose cowl assembly being damaged by chafing. Compliance date required by UK CAA extended by three months.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"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 on a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection/repair of nose cowl extinguisher pipes."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined applicability criterion (aircraft serial numbers)","Single mandatory action with reference to external technical document (SB 26-A29)","No nested exceptions or conditional logic","Simple compliance deadline (single fixed date)","Minimal cross-referencing (only to manufacturer service bulletin)"],"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) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific British Aerospace BAe 146 aircraft to inspect and fix a problem with the **fire extinguisher pipe in the nose cowl** (the front engine cover). The pipe can get damaged by **chafing** (rubbing against another surface), which could prevent the fire suppression system from working properly in an emergency.\n\n**Who it affects:** Operators of BAe 146 Series 100, 100A, 200, 200A, 300, and 300A aircraft with specific serial numbers up to E1152, E2156, and E3157 respectively.\n\n**What must be done:** Follow the instructions in **British Aerospace Service Bulletin 26-A29 Revision 2** — a technical document from the manufacturer detailing the inspection and repair procedure.\n\n**When:** Before 31 May 1991.\n\n**Why it matters:** Fire suppression systems are critical for passenger and crew safety. A damaged extinguisher pipe could fail during an engine fire, with potentially catastrophic consequences. The directive ensures this known defect is fixed across the affected fleet."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD does not expand the affected fleet beyond the listed serial-number ranges; it mandates compliance with SB 26‑A29 Revision 2 and sets a compliance date (Compliance). It explicitly exempts operators who have already complied with the SB from additional inspections (Note). The Background records that the UK CAA extended the compliance date, but the AD itself only restates the required action and deadline, so the substantive scope remains unchanged."},"complexity_factors":["Dependence on an external technical document: mandatory BAe 146 SB 26‑A29 Revision 2 (Requirement) — AD does not set technical steps itself","Serial-number-limited applicability: different upper serial limits for Series 100/200/300 require fleet-by-fleet checks (Applicability)","Hard compliance deadline: a single specified date (Compliance) creates scheduling/operational impacts","Exemption clause: operators who already complied with SB 26‑A29 are carved out (Note), requiring record checks","Sparse procedural detail in the AD: the operator must consult the SB for actions and intervals, increasing administrative burden","Regulatory cross-reference to UK CAA action and an extended compliance date in background may require operators to track multiple authority communications (Background)"],"plain_english_summary":"Requires operators of specified BAe 146 Series 100/200/300 aeroplanes (only up to listed serial numbers) to carry out the work described in mandatory BAe 146 Service Bulletin 26‑A29 Revision 2 to inspect and rectify the nose‑cowl extinguisher pipe. The work must be done before 31 May 1991. Operators bear the cost of compliance; the Civil Aviation Safety Authority enforces the requirement. Operators already compliant with the service bulletin are not required to repeat inspections."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-31-nose-cowl-extinguisher-pipe","history":"/api/acts/ad-bae-146-31-nose-cowl-extinguisher-pipe/history","analysis":"/api/acts/ad-bae-146-31-nose-cowl-extinguisher-pipe/analysis","conflicts":"/api/acts/ad-bae-146-31-nose-cowl-extinguisher-pipe/conflicts","importantCases":"/api/acts/ad-bae-146-31-nose-cowl-extinguisher-pipe/important-cases","documents":"/api/acts/ad-bae-146-31-nose-cowl-extinguisher-pipe/documents"}}