{"id":"F2006B07493","name":"AD/TSA-600/28 - Fuel Pressure Gauge - Modification","slug":"ad-tsa-600-28-fuel-pressure-gauge-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49950,"registerId":"commonwealth-F2006B07493-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TSA-600/28 - Fuel Pressure Gauge - Modification","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)  Aerostar (Piper/Ted Smith) 600 and 700 Series Aeroplanes\n\n \n\nAD/TSA-600/28 Fuel Pressure Gauge - Modification 11/80\n\nApplicability: Model 601 and 601P series.\n\n \n\nRequirement: Mark the left hand and right hand engine fuel pressure gauges with a yellow arc over the 12 psi to 18 psi range.\n\n \n\nNote: FAA AD 80-18-03 Amdt. 39-3900 refers.\n\n \n\nCompliance: Within 100 hours time in service after 30 November 1980.\n\n \n\nBackground:  This directive is issued to prevent possible engine failures due to excessively lean fuel/air mixture operation and supplements corresponding flight manual amendment.\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\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a discrete, single-purpose safety directive. It has not expanded beyond its original intent of requiring a specific gauge modification to prevent engine failure."},"complexity_factors":["Single, unambiguous requirement (marking a gauge)","No defined terms section","No cross-references to other legislation (only a reference to a related FAA directive for context)","No conditional logic or exceptions","Extremely short document (approximately 150 words of substantive content)","Clear applicability statement limiting scope to specific aircraft models"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific repairs or modifications to aircraft.\n\n**What it does:**\nOwners and operators of certain **Aerostar 601 and 601P series aeroplanes** must mark their fuel pressure gauges with a **yellow arc between 12 and 18 psi** on both the left and right engines.\n\n**Why it matters:**\nThis marking warns pilots when fuel pressure drops into a dangerous range. Low fuel pressure can cause engines to run too \"lean\" (too much air, not enough fuel), which can lead to **engine failure** in flight. The yellow arc acts as a visual alert to prevent pilots from operating in this unsafe zone.\n\n**Who must comply:**\nAnyone operating the affected Aerostar models must complete this modification within **100 hours of flight time** after 30 November 1980.\n\n**Key point:**\nThis directive works alongside an updated flight manual — the gauge marking reinforces what pilots should already know, but makes it impossible to miss during flight."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument, as written, implements a single, specific change: marking the left and right engine fuel pressure gauges with a yellow arc from 12 psi to 18 psi on Model 601 and 601P aeroplanes, to be done within a stated timeframe. The text asserts that the change supplements a flight manual amendment and references an FAA AD, but it does not expand or narrow the set of affected aircraft or the required modification beyond that specific marking. There is no indication within this text that the scope has changed from that stated intent (Applicability; Requirement; Compliance; Background; Note)."},"complexity_factors":["Narrow technical scope: single physical marking on existing instruments (Requirement)","Clear applicability to a limited set of models (Model 601 and 601P) (Applicability)","Simple, single compliance action with a fixed deadline (Compliance)","No procedural detail in the text about how to perform or verify the marking (increases implementation ambiguity slightly) (Requirement; Compliance)","Cross-reference to an external FAA AD without incorporating its content (Note)"],"plain_english_summary":"What this instrument changes mechanically\n\n- It requires that the left-hand and right-hand engine fuel pressure gauges on Aerostar (Piper/Ted Smith) Model 601 and 601P aeroplanes be marked with a yellow arc covering the 12 psi to 18 psi range. (Requirement; Applicability)\n\nWho it affects and who decides\n\n- The requirement applies to aircraft of Model 601 and 601P series. Operators or owners of those aircraft are the parties who must ensure the marking is applied. (Applicability; Requirement)\n\nWhen it must be done\n\n- The marking must be completed within 100 hours time in service after 30 November 1980. (Compliance)\n\nStated reason for the change\n\n- The directive states its purpose is to prevent possible engine failures caused by operating with an excessively lean fuel/air mixture and is a supplement to a corresponding flight manual amendment. (Background)\n\nPractical mechanics and immediate effects on behaviour\n\n- The mechanical change is limited to a visible marking on two existing cockpit instruments; no replacement of instruments is mandated—only the addition of a yellow arc over a specified pressure range. (Requirement)\n- In practice, an operator or maintenance provider must apply the marking to each affected gauge within the compliance window. This causes an operational action (scheduling and carrying out the marking) rather than changing normal flight operations immediately. (Requirement; Compliance)\n\nCosts, incentives and trade-offs (source-grounded)\n\n- Who pays: The operator or aircraft owner will need to arrange and bear the cost of applying the marking (labour, materials or maintenance shop time). This follows from the applicability and the requirement directing the physical modification be made to the aircraft. (Applicability; Requirement)\n- Compliance burden: The text imposes a single, discrete maintenance action (adding a coloured arc). The directive does not specify method, qualifications, or certification paperwork in this text; those details, if required, would come from maintenance standards or the flight manual amendment referenced. The immediate compliance burden appears limited to the marking action and scheduling it within the stated time window. (Requirement; Compliance; Background)\n- Incentives: Operators are incentivised to perform the marking to meet the compliance deadline and to follow the stated safety purpose. The directive does not create recurring obligations beyond the marking requirement as written. (Requirement; Compliance; Background)\n- Opportunity cost: Time spent by maintenance personnel and aircraft downtime during marking is the opportunity cost; the instrument does not quantify that. (Requirement; Compliance)\n- Implementation risk: The directive relies on the marking being applied correctly and visibly; incorrect or omitted marking would reduce the intended effect. The text does not specify verification procedures or penalties in this extract. (Requirement)\n\nInteraction with other instruments\n\n- The directive notes a related FAA airworthiness directive (FAA AD 80-18-03 Amdt. 39-3900). That suggests this action is harmonised with at least one foreign authority's requirement, but the present text does not incorporate the FAA document’s content. (Note)\n\nNet effect summary\n\n- The directive imposes a limited, one-off physical modification (a yellow arc on two fuel pressure gauges) on a defined set of aircraft, to be completed within a fixed timeframe. The owner/operator bears the cost and responsibility for implementation; the stated purpose is to reduce the risk of engine failure associated with lean fuel/air mixtures. (Applicability; Requirement; Compliance; Background)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-tsa-600-28-fuel-pressure-gauge-modification","history":"/api/acts/ad-tsa-600-28-fuel-pressure-gauge-modification/history","analysis":"/api/acts/ad-tsa-600-28-fuel-pressure-gauge-modification/analysis","conflicts":"/api/acts/ad-tsa-600-28-fuel-pressure-gauge-modification/conflicts","importantCases":"/api/acts/ad-tsa-600-28-fuel-pressure-gauge-modification/important-cases","documents":"/api/acts/ad-tsa-600-28-fuel-pressure-gauge-modification/documents"}}