{"id":"F2006B03630","name":"AD/BEECH 1900/12 - Pneumatic Air System Plumbing","slug":"ad-beech-1900-12-pneumatic-air-system-plumbing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43220,"registerId":"commonwealth-F2006B03630-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 1900/12 - Pneumatic Air System Plumbing","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 1900 Series Aeroplanes\n\nAD/BEECH 1900/12 Pneumatic Air System Plumbing 11/95\n\nApplicability: This Directive is applicable to the following aircraft:\n\nModel Serial Numbers\n\n1900 UA-2 and UA-3\n\n1900C UB-1 through UB-74 and UC-1 through UC-174\n\n1900C (C12J) UD-1 through UD-6\n\n1900D UE-2 through UE-115\n\nRequirement: Modify the plumbing of the pneumatic air system in accordance with the instructions provided with the following Beechcraft kits and as specified in the applicable Beechcraft Mandatory Service Bulletin:\n\n| Models         | Kit Number               | Service Bulletin |\n| -------------- | ------------------------ | ---------------- |\n| 1900 and 1900C | 118-9003-1 or 118-9003-3 | 2539             |\n| 1900D          | 129-9010-1 or 118-9010-3 | 2591             |\n\nNote: FAA AD 95-14-02 Amdt 39-9294 refers and supersedes FAA AD 91-24-15 Amdt 39-8173.\n\nCompliance: Within 1,000 hours time in service after 12 October 1995 or by 31 December 1997, whichever occurs first.\n\nBackground: This Directive supersedes and cancels AD/BEECH 1900/6 which mandated certain modification of the instrument/pneumatic air system. Following eight additional reports of moisture freezing in the pneumatic air system plumbing of Model 1900 and 1900C aircraft, fitted with the same modification as that required by AD/BEECH 1900/6, the FAA determined that further modifications were required. Recent testing of the Model 1900D by the FAA also indicates that the design of the pneumatic air system on these aircraft is also conducive to moisture freezing. Actions specified by this Directive are designed to prevent ice formation in the pneumatic air system, which, if not detected, could result in the vacuum for the deice boot operation being unavailable which could result in the subsequent loss of the aircraft.\n\nFederal Register of Legislative Instruments F2006B03630","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific safety defect in the pneumatic air system of specific Beechcraft 1900 variants. It supersedes a previous AD on the same topic but does not expand beyond the original safety purpose of preventing ice formation in the pneumatic system."},"complexity_factors":["Single, specific technical requirement with clear kit numbers and service bulletin references","Limited applicability — only three aircraft models with defined serial number ranges","Simple compliance deadline structure (whichever comes first of two dates)","No nested definitions or extensive interpretation sections","Straightforward background explanation without cross-references to other legislation beyond the superseded AD and related FAA directives","Total length is approximately one page"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of certain Beechcraft 1900 series aeroplanes in Australia to modify pneumatic air system plumbing using specified Beechcraft kits to stop moisture freezing. It addresses failures that can cut vacuum to wing de-ice boots—risking ice accumulation and loss of control—and replaces an earlier, ineffective AD after eight reported freezing incidents. Compliance was required by the earlier of 1,000 flight hours after 12 Oct 1995 or 31 Dec 1997."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This AD expands the scope compared with the earlier AD/BEECH 1900/6. The earlier AD required certain modifications to the instrument/pneumatic system; following additional freezing reports and FAA testing, this AD mandates further plumbing changes and explicitly includes the 1900D model (previously not covered). Concretely, the population of affected aircraft was increased (addition of 1900D serial ranges), and operators must install updated kits per Beechcraft Mandatory Service Bulletins. The AD therefore grows beyond the earlier directive’s narrower modification by requiring broader or different plumbing changes to address continued reports of moisture freezing."},"complexity_factors":["Relatively short single-subject AD (plumbing modification)","Multiple aircraft model and serial-number ranges listed in Applicability (adds bookkeeping complexity)","Two alternative kit numbers provided for each model group (operators must choose/install the correct kit)","Dependence on external documents: two Beechcraft Mandatory Service Bulletins (2539, 2591) and kit instructions","Cross-reference to prior and external FAA ADs (FAA AD 95-14-02 and superseded 91-24-15)","Single conditional compliance deadline (whichever occurs first: 1,000 hours TIS after 12 Oct 1995 or 31 Dec 1997)"],"plain_english_summary":"**What this directive requires (mechanics)**\n\n- Modify the pneumatic (air) plumbing on Beechcraft 1900 series aeroplanes listed below by installing the specified Beechcraft kits and following the instructions in the applicable Beechcraft Mandatory Service Bulletin (SB).\n- Applicable kit/SB pairs:\n  - Models 1900 and 1900C — kits 118-9003-1 or 118-9003-3; Service Bulletin 2539\n  - Model 1900D — kits 129-9010-1 or 118-9010-3; Service Bulletin 2591\n- The modification must be done within 1,000 hours time in service after 12 October 1995, or by 31 December 1997, whichever comes first. [See: Requirement; Compliance]\n\n**Which aircraft and operators are affected**\n\n- Affects Beechcraft 1900 series airframes with the serial-number ranges listed in the Applicability section: 1900 UA-2/UA-3; 1900C UB-1–UB-74 and UC-1–UC-174; 1900C (C12J) UD-1–UD-6; 1900D UE-2–UE-115. Operators of those specific aircraft must comply. [See: Applicability]\n\n**Why the directive exists (stated purpose) and the evidence given**\n\n- The AD is intended to prevent moisture from freezing inside the pneumatic plumbing. The stated risk is that frozen moisture can make the vacuum source for deice boot operation unavailable, which could lead to loss of the aircraft if ice protection fails. The Background notes additional reports of moisture freezing after an earlier AD and FAA testing that showed the 1900D plumbing is also vulnerable. [See: Background]\n\n**Who pays, who decides, and what changes in behaviour**\n\n- Who pays: aircraft operators (airlines, charter operators, owners) must acquire the kit(s) and pay for installation labour and associated downtime.\n- Who decides: the Civil Aviation Safety Authority (CASA) enforces the directive; the modification work follows Beechcraft’s supplied kit instructions and the referenced Mandatory Service Bulletins. The directive also references and aligns with FAA airworthiness directives. [See: Requirement; Note]\n- Behaviour change required: operators must schedule and perform the plumbing modification within the mandated timeframe, update maintenance records to show compliance, and operate with the modified pneumatic plumbing thereafter.\n\n**Costs, incentives and trade-offs (practical testing of the stated purpose)**\n\n- Direct costs: purchase of kit parts, technician labour, and aircraft out-of-service time for installation. Those are borne by operators.\n- Operational trade-offs: installation may require scheduled maintenance slots, potentially increasing short-term costs and reducing available flying time. That is the opportunity cost.\n- Safety benefit: the modification aims to reduce the risk of pneumatic icing and loss of vacuum to deice boots. The directive cites prior incident reports and FAA testing as justification.\n- Compliance burden and implementation risk: the AD depends on external documents (Beechcraft Mandatory Service Bulletins and kit instructions). Compliance depends on parts availability and correct installation per SB; incorrect or delayed installation leaves the aircraft exposed to the identified risk.\n- Market and competitive effects: costs are concentrated on operators of the affected serial-numbered aircraft; benefits (reduced accident risk) are concentrated to those operators, their passengers and crew. There is no direct subsidy or compensation mechanism in the directive; private operators bear the cost.\n\n**Cross-references and continuity**\n\n- This Directive supersedes and cancels AD/BEECH 1900/6, extending or changing the required modification after further incidents and FAA testing. It also refers to FAA AD 95-14-02 (which superseded FAA AD 91-24-15). [See: Background; Note]\n\n(Sections referenced in brackets are the parts of the AD that state the applicability, requirement, compliance date and background justification.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-1900-12-pneumatic-air-system-plumbing","history":"/api/acts/ad-beech-1900-12-pneumatic-air-system-plumbing/history","analysis":"/api/acts/ad-beech-1900-12-pneumatic-air-system-plumbing/analysis","conflicts":"/api/acts/ad-beech-1900-12-pneumatic-air-system-plumbing/conflicts","importantCases":"/api/acts/ad-beech-1900-12-pneumatic-air-system-plumbing/important-cases","documents":"/api/acts/ad-beech-1900-12-pneumatic-air-system-plumbing/documents"}}