{"id":"F2006B04274","name":"AD/BEECH 90/91 - Pressurisation Control System Pneumatic Tubing Inspection","slug":"ad-beech-90-91-pressurisation-control-system-pneumatic-tubing-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44080,"registerId":"commonwealth-F2006B04274-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 90/91 - Pressurisation Control System Pneumatic Tubing Inspection","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)  \nBeechcraft 90 and 65-90 (King Air) Series Aeroplanes\n\nAD/BEECH 90/91 Pressurisation Control System\n\nPneumatic Tubing Inspection\n\n  \n2/98\n\nApplicability: All Beech 90 series aircraft with serial numbers LJ-683 through LJ-1463, LW-177 through LW-347, LA-1 through LA-236 and LL-1 through LL-61.\n\nRequirement: Inspect and re-route the environmental air conditioning and pressurisation control system pneumatic tubing in accordance with Raytheon Aircraft Mandatory SB 2676 dated January, 1997.\n\nNote: FAA AD 97-23-17 Amdt 39-10207 and DGAC AD 97-353-(AB) refers.\n\nCompliance: Unless previously carried out at the next schedule inspection but no later than the next 200 hours’ time in service from the effective date of this Directive.\n\nThis airworthiness directive becomes effective on 29 January 1998.\n\nBackground: This directive being raised on receipt of FAA AD and advice that when a pilot requested a passenger to open the cabin door a passenger was injured when ejected from the aircraft onto the tarmac.\n\nSubsequent investigation by the manufacturer confirmed that heat from the co pilot’s foot warmer outlet and associated plumbing can soften the plastic pressurisation control system pneumatic tubing sufficiently to cause permanent collapse when the line is subject to vacuum. This will result in loss of vacuum to the outflow/safety valves and this could prevent depressurisation of the aircraft. If the cabin door is operated with the aircraft partially pressurised injury to passengers and/or ground personnel may occur.\n\nThe de-icing indicator pneumatic tubing also has the potential for heat damage from the co-pilot’s foot warmer. This tubing could rupture rendering the de-icing indicator inoperative.","sortOrder":0}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive targets the specific hazard identified by the manufacturer and follows the FAA AD; it applies only to listed serial numbers and prescribes the manufacturer’s rerouting inspection—there is no indication in the text that the Directive broadens or narrows the risk scope beyond that original safety focus."},"complexity_factors":["Technical remedy delegated to a manufacturer service bulletin (Raytheon SB 2676) rather than fully described in the Directive.","Applicability limited to specific serial‑number ranges, requiring operators to verify eligibility.","Safety‑critical nature: failure modes include collapsed tubing under vacuum and ruptured de‑icing indicator lines.","Fixed compliance window (next scheduled inspection or within 200 hours) creates operational scheduling constraints.","Cross‑references to FAA and DGAC ADs add regulatory alignment considerations."],"plain_english_summary":"**What this does:** Owners/operators of the listed Beechcraft 90/65‑90 series aeroplanes must inspect and re‑route the environmental air‑conditioning and pressurisation pneumatic tubing in accordance with Raytheon Mandatory Service Bulletin 2676. Compliance is required at the next scheduled inspection or within 200 flight hours.  \n\n**Why it matters:** The measure responds to manufacturer findings that heat from the co‑pilot’s foot warmer can soften or rupture plastic tubing, risking loss of vacuum to outflow/safety valves (preventing depressurisation) or loss of the de‑icing indicator. Operators pay for and schedule the maintenance action."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific mechanical defect in a specific aircraft series. The scope remains precisely limited to the pressurisation tubing issue identified in the background."},"complexity_factors":["Single, specific mechanical requirement (inspect and re-route tubing)","Limited applicability (specific serial number ranges only)","Clear compliance deadline (next inspection or 200 hours)","No nested exceptions or conditional logic","Only 4 defined elements: applicability range, requirement reference, compliance timeframe, and effective date","Straightforward causal chain in background section"],"plain_english_summary":"This AD requires owners/operators of certain Beechcraft King Air 90-series aircraft to inspect and re‑route plastic air tubes in the pressurisation and air‑conditioning system.  \n\nIt addresses heat damage from the co‑pilot’s foot warmer that can soften and collapse those tubes, risking loss of depressurisation control (with potential for sudden ejection when a door is opened) and failure of the de‑icing indicator. Compliance is at the next inspection or within 200 flight hours."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-90-91-pressurisation-control-system-pneumatic-tubing-inspection","history":"/api/acts/ad-beech-90-91-pressurisation-control-system-pneumatic-tubing-inspection/history","analysis":"/api/acts/ad-beech-90-91-pressurisation-control-system-pneumatic-tubing-inspection/analysis","conflicts":"/api/acts/ad-beech-90-91-pressurisation-control-system-pneumatic-tubing-inspection/conflicts","importantCases":"/api/acts/ad-beech-90-91-pressurisation-control-system-pneumatic-tubing-inspection/important-cases","documents":"/api/acts/ad-beech-90-91-pressurisation-control-system-pneumatic-tubing-inspection/documents"}}