{"id":"F2006B05010","name":"AD/CESSNA 177/16 - Oil Pressure Gauge Line","slug":"ad-cessna-177-16-oil-pressure-gauge-line","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44920,"registerId":"commonwealth-F2006B05010-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 177/16 - Oil Pressure Gauge Line","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)  Cessna 177 Series Aeroplanes\n\n \n\nAD/CESSNA 177/16 Oil Pressure Gauge Line 3/74\n\nApplicability: Model 177 with S/Nos. 17700001 to 17701160.\n\n \n\nRequirement: 1. Inspect the oil pressure gauge line along the entire length from firewall to instrument panel, paying particular attention to the following areas:\n\n \n\n(a)     in the vicinity of the flap control switch;\n\n \n\n(b)     adjacent to the blast cooling nozzle of those aircraft fitted with radio cooling equipment.\n\n \n\n2. Adjust the line as required to prevent chafing. Compliance: Within 100 hours time in service after 29 March 1974.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive sets a targeted maintenance requirement for a defined subset of Cessna 177 aircraft (serial numbers 17700001–17701160) to inspect and adjust the oil pressure gauge line to prevent chafing (Applicability; Requirement 1–2). The text does not expand or narrow applicability beyond those serial numbers nor impose additional unrelated obligations; it therefore does not change scope from its expressed purpose of addressing chafing of the oil pressure gauge line."},"complexity_factors":["Limited applicability to a defined set of serial numbers (Applicability) — reduces scope complexity.","Small number of concrete actions (inspect full length; pay particular attention to two locations; adjust as required) — straightforward duties (Requirement 1–2).","Open-ended corrective step: “adjust the line as required” leaves method and acceptance criteria to maintenance judgement — introduces procedural discretion and variability in compliance.","Compliance measured in flight hours with a fixed historical start date (100 hours TIS after 29 March 1974) — requires record-checking and time accounting.","Inspection area references (flap control switch; blast cooling nozzle when radio cooling equipment fitted) require aircraft-specific familiarity and may affect access difficulty (Requirement 1(a)–(b))."],"plain_english_summary":"What this instrument does (mechanically)\n\n- Requires the owner/operator or maintenance organisation to inspect the oil pressure gauge line along its full length from the firewall to the instrument panel on specified Cessna 177 aeroplanes (Applicability).\n- Requires particular attention to two spots: (a) near the flap control switch and (b) next to the blast cooling nozzle on aircraft fitted with radio cooling equipment (Requirement 1(a)–(b)).\n- Requires any adjustment needed to prevent chafing of the line (Requirement 2).\n- Sets a deadline for complying with these actions: within 100 hours time in service after 29 March 1974 (Compliance).\n\nOfficial stated purpose (as expressed in the instrument)\n\n- The instrument’s operative requirement (Requirement 2) is to prevent chafing of the oil pressure gauge line. The title and the text identify the oil pressure gauge line and chafing risk as the subject of the directive.\n\nWho this affects and who pays\n\n- The directive applies to Cessna 177 aircraft with serial numbers 17700001 to 17701160 (Applicability). Those aircraft’ owners/operators are responsible for arranging and paying for the inspection and any adjustments called for by the directive (Requirement 1–2; Compliance). If a maintenance organisation performs the work, the operator will incur labour and any part/replacement costs.\n\nWhat decisions are left to operators or maintainers (discretion)\n\n- The directive requires inspection and that the line be \"adjust[ed] as required\" to prevent chafing (Requirement 2). It does not prescribe a specific repair method, clearances, or parts to use. That leaves professional judgement to the person or organisation performing the work about what adjustment or corrective action is sufficient.\n\nCompliance burden, timing and practical points\n\n- The physical task is an inspection along the entire line from firewall to instrument panel; access, routing and the presence of radio cooling equipment are concrete factors to check (Requirement 1 and 1(b)).\n- The compliance time is expressed in flight hours (100 hours time in service) counted from a historical date (29 March 1974) (Compliance). That creates a finite window within which the inspection and any required adjustments had to be completed.\n\nIncentives, trade-offs and implementation risks (mechanistic analysis)\n\n- Incentive: Owners/operators gain by reducing the chance that the oil pressure gauge line will chafe (explicit requirement and title). They therefore have an operational incentive to perform the inspection and adjustment to avoid chafing-related faults.\n- Costs and opportunity cost: The directive imposes direct inspection and potential adjustment costs (labour, possible parts). Those resources are diverted from other maintenance or operational priorities.\n- Implementation risk: Effectiveness depends on the quality of inspection and the judgement used to \"adjust the line as required.\" Accessibility of the line and the ability to identify the specified areas (flap control switch vicinity; blast cooling nozzle where radio cooling equipment is fitted) affect how reliably chafing can be found and corrected (Requirement 1(a)–(b)).\n- Bureaucratic discretion and enforceability: The instrument sets obligations (inspect and adjust) but leaves method and acceptance criteria to maintainers’ judgement; enforcement would therefore focus on whether the inspection and corrective actions occurred within the required timeframe rather than on a prescribed technical fix.\n\nNet mechanical effect\n\n- Operators of the listed Cessna 177 serial numbers must inspect and, if necessary, adjust the oil pressure gauge line to prevent chafing within the stated compliance window. The practical outcome is a required maintenance action relying on technician assessment of what constitutes adequate adjustment (Requirement 1–2; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on oil pressure gauge line inspection for a limited aircraft model range. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 specific inspection requirements with clear locations","Single defined applicability criterion (serial number range)","Simple compliance deadline (100 hours time in service after fixed date)","No cross-references to other legislation or regulations","No conditional logic or nested exceptions","Straightforward mechanical safety directive with minimal legal drafting"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of certain **Cessna 177 model aeroplanes** (specifically those with serial numbers 17700001 through 17701160) to inspect the oil pressure gauge line that runs from the firewall to the instrument panel.\n\n**Why it matters:**\nThe directive targets a potential safety hazard where the oil pressure gauge line could **chafe** (wear away through rubbing against other parts) in two specific areas:\n- Near the flap control switch\n- Next to the blast cooling nozzle on aircraft with radio cooling equipment\n\nWorn or damaged oil lines can leak oil, leading to engine failure or fire.\n\n**What must be done:**\n- **Inspect** the entire length of the oil pressure gauge line\n- **Adjust** the line as needed to prevent rubbing/chafing\n- **Complete within** 100 hours of flight time after 29 March 1974\n\n**Who it affects:**\nOwners and operators of early-model Cessna 177 aircraft with the specified serial numbers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-177-16-oil-pressure-gauge-line","history":"/api/acts/ad-cessna-177-16-oil-pressure-gauge-line/history","analysis":"/api/acts/ad-cessna-177-16-oil-pressure-gauge-line/analysis","conflicts":"/api/acts/ad-cessna-177-16-oil-pressure-gauge-line/conflicts","importantCases":"/api/acts/ad-cessna-177-16-oil-pressure-gauge-line/important-cases","documents":"/api/acts/ad-cessna-177-16-oil-pressure-gauge-line/documents"}}