{"id":"F2006B04942","name":"AD/CESSNA 150/44 - Instrument Panel Light Dimming Rheostat","slug":"ad-cessna-150-44-instrument-panel-light-dimming-rheostat","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44796,"registerId":"commonwealth-F2006B04942-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 150/44 - Instrument Panel Light Dimming Rheostat","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)  \nCessna 150, F150, 152 & F152 Series Aeroplanes\n\nAD/CESSNA 150/44 Instrument Panel Light Dimming Rheostat 3/94\n\n| Applicability: | Cessna aircraft as follows;Model | Serial Numbers              |\n| -------------- | -------------------------------- | --------------------------- |\n|                | 150F, 150G, 150H and 150J        | 15061533 through 15071128   |\n|                | F150F, F150G, F150H and F150J    | F150-0001 through F150-0529 |\n\nRequirement: Unless previously accomplished, replace the existing instrument panel light dimming rheostat (some installations will also require the fitting of a doubler) in accordance with the Accomplishment Instructions of Cessna Single Engine Service Bulletin SEB92-33 Revision 2 dated 10 September 1993.\n\nNote: FAA AD 93-24-15 Amdt 39-8764 refers.\n\nCompliance: Prior to 3 October 1994.\n\nBackground: The FAA has advised of a report of an inflight fire in a Cessna Model 172.\n\nThe fire was caused by a short in the electrical wiring controlled by the instrument panel light dimming rheostat. This Directive requires the rheostat to be replaced with an improved version, which is both current-limiting and heat-protected, thus decreasing the probability of an inflight fire being caused by a defective rheostat.","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 known defect in specific aircraft. It has not expanded beyond its original purpose of preventing in-flight fires caused by a particular faulty component."},"complexity_factors":["Very short document (under 300 words)","Only 2 defined applicability criteria (model numbers and serial number ranges)","Single, unambiguous requirement with reference to external technical standard (Cessna Service Bulletin)","No nested exceptions or conditional logic — compliance is mandatory unless already done","Clear compliance date with no alternative methods stated"],"plain_english_summary":"This is a **safety order** (called an \"Airworthiness Directive\") issued by Australia's Civil Aviation Safety Authority. It applies to specific models of **Cessna 150 series aircraft** built between certain serial numbers.\n\n**What it does:**\n- Requires owners/operators to **replace a faulty part** — specifically, the dimmer switch (rheostat) that controls how bright the instrument panel lights are.\n- The old rheostat can overheat and cause **in-flight fires** due to electrical shorts. The new version has built-in safety features to prevent this.\n\n**Who it affects:**\n- Owners and operators of specific Cessna 150, F150, 152 and F152 aircraft (listed by model and serial number in the table).\n\n**Why it matters:**\n- **Flight safety.** A fire in the cockpit during flight is obviously extremely dangerous. This directive mandates a fix before a deadline (3 October 1994) to prevent that risk.\n\n**Key deadline:** The replacement had to be done before 3 October 1994."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The Directive responds to an inflight fire reported in a Cessna Model 172 (Background) but mandates replacement on specified Cessna 150/F150 and 152/F152 serial ranges (Applicability). That indicates the scope extends beyond the specific model where the incident occurred to other types using the same rheostat; the legal effect is a targeted retrofit across listed serial numbers by the stated compliance date."},"complexity_factors":["Narrow, serial‑numbered applicability (specific Cessna 150/F150 and 152/F152 serial ranges) increases administrative tracking (Applicability).","Mandatory physical retrofit required to Service Bulletin instructions — technical work needing parts and certified maintenance resources (Requirement: Cessna SEB92‑33 Rev 2).","Some installations may require a doubler, adding variability in labour/time/cost per aircraft (Requirement note).","Fixed compliance deadline (prior to 3 October 1994) concentrates workload and parts procurement (Compliance).","Cross‑reference to FAA AD 93‑24‑15 creates regulatory alignment/coordination considerations (Note).","Safety‑critical electrical failure motive (inflight fire reported in Model 172) raises inspection and evidentiary expectations for compliance (Background)."],"plain_english_summary":"**What it does:** Requires owners/operators of specified Cessna 150/F150 and 152/F152 aeroplanes (listed by serial number) to replace the instrument‑panel light dimming rheostat with an improved, current‑limiting, heat‑protected unit per Cessna Service Bulletin SEB92‑33 Rev 2.\n\n**Who pays and why it matters:** The aircraft owner/operator must arrange and pay for the replacement (and any required doubler) before 3 October 1994 (Requirement; Compliance). The change aims to reduce the risk of an inflight fire caused by a defective rheostat (Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-150-44-instrument-panel-light-dimming-rheostat","history":"/api/acts/ad-cessna-150-44-instrument-panel-light-dimming-rheostat/history","analysis":"/api/acts/ad-cessna-150-44-instrument-panel-light-dimming-rheostat/analysis","conflicts":"/api/acts/ad-cessna-150-44-instrument-panel-light-dimming-rheostat/conflicts","importantCases":"/api/acts/ad-cessna-150-44-instrument-panel-light-dimming-rheostat/important-cases","documents":"/api/acts/ad-cessna-150-44-instrument-panel-light-dimming-rheostat/documents"}}