{"id":"F2006B04999","name":"AD/CESSNA 170/70 - Fuel Mixture Setting","slug":"ad-cessna-170-70-fuel-mixture-setting","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44908,"registerId":"commonwealth-F2006B04999-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nCessna 170, 172, F172, FR172 and 175 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/CESSNA 170/70 Fuel Mixture Setting 11","sectionType":"part","heading":"AD/CESSNA 170/70 Fuel Mixture Setting 11/2001","content":"# AD/CESSNA 170/70 Fuel Mixture Setting 11/2001\n\nApplicability: Cessna models 172R and 172S, all serial numbers.\n\nRequirement: 1. Carry out an engine idle speed and fuel mixture setting check by:\n\n    With engine oil temperature between 120 and 150 degrees Fahrenheit; and\n\n    b. With the throttle hard at the ground idle stop; and\n\n    c. Check the engine revolutions per minute (RPM) is between 575 and 625 RPM; and\n\n    d. Check RPM rises between 10 and 50 RPM when the mixture control is rotated slowly counter clockwise to idle cut-off.\n\nThe pilot in command, other than a student pilot, may carry out the engine idle speed and fuel mixture setting check. Compliance is recorded by entering in the Aircraft Log Book; “AD/CESSNA 170/70 carried out”. Any discrepancy disclosed in carrying out the engine idle speed and fuel mixture setting check shall be recorded in the “Maintenance required” column of the aircraft maintenance release or equivalent document.\n\n2. Amend the applicable Pilot’s Operating Handbook (POH) and Pilot’s Check List in accordance with the accomplishment instructions detailed in Cessna Service Bulletin SB01-11-02\n\nThe certificate of registration holder may carry out the amendment of the POH and Pilot’s Check List; CAR (1988) 55 (4) refers.\n\nNote: FAA AD 2001-06-17 refers.\n\nCompliance: Unless previously accomplished, within 10 hours time in service from the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 1 November 2001.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD is narrowly focused on correcting an identified unsafe condition by requiring a one‑off operational check and updating the POH/checklist. It does not expand the regulatory scope beyond that original corrective purpose: applicability is limited to specific aircraft models (172R and 172S), required actions are limited and time‑bound (single compliance within 10 hours), and implementation depends on an external manufacturer service bulletin. There is no substantive enlargement of affected parties, duration, or ongoing regulatory obligations compared with the AD’s stated corrective intent."},"complexity_factors":["Short, single‑issue AD with two discrete required actions (check + POH/checklist amendment)","Few cross‑references: one manufacturer service bulletin (Cessna SB01‑11‑02) and one FAA AD (2001‑06‑17)","One clear applicability statement (Cessna 172R and 172S, all serial numbers)","A small number of measurable conditions for the check (4 sub‑conditions: oil temp, throttle position, RPM range, RPM rise on mixture manipulation)","Permits PIC (except student) to perform check — introduces minor regulatory nuance regarding who may perform maintenance‑type tasks","Simple compliance timeframe (within 10 hours time in service)","Record‑keeping requirements (logbook entry; recording discrepancies in maintenance release) but no complex certification or repeated inspections","No nested exceptions or multiple conditional branches"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Applies to: Cessna 172R and 172S aeroplanes (all serial numbers). (Applicability clause)\n\n- Requires two things. (Requirement clause)\n  1. An engine idle speed and fuel‑mixture check performed under specific engine and control settings:\n     - engine oil temperature 120–150 °F;\n     - throttle hard at the ground idle stop;\n     - idle engine speed (RPM) must be 575–625 RPM;\n     - when the mixture control is slowly rotated counter‑clockwise to idle cutoff, RPM must rise by 10–50 RPM.\n     - Any discrepancy found must be recorded in the aircraft maintenance release (\"Maintenance required\" column).\n     - The pilot‑in‑command (PIC), other than a student pilot, is explicitly permitted to carry out this check and must record compliance in the Aircraft Log Book by entering: “AD/CESSNA 170/70 carried out”.\n  2. Amend the aircraft Pilot’s Operating Handbook (POH) and the Pilot’s Checklist in accordance with the instructions in Cessna Service Bulletin SB01‑11‑02.\n     - The certificate of registration holder (the owner/operator) is permitted to carry out the POH/checklist amendment (reference to CAR (1988) 55(4)).\n\n- Timing (Compliance): If not already done, both actions must be completed within 10 hours time in service from the AD’s effective date.\n\n- Cross references: The AD notes an associated FAA AD (FAA AD 2001‑06‑17) and relies on the Cessna service bulletin for the POH/checklist amendment instructions.\n\nWho pays, who decides, and what changes\n\n- Who decides: The CASA delegate issued the AD; the PIC (except student pilots) may perform the check; the certificate of registration holder may amend the POH/checklist; any maintenance work beyond the check would typically be decided by the owner/operator or maintenance organisation.\n\n- Who pays: Aircraft owners/operators bear the direct costs — time to perform the check, the administrative cost of logbook and POH/checklist updates, and any repair or adjustment if the check discloses a discrepancy. If a licensed maintenance organisation is used instead of the PIC, labour costs apply.\n\n- Behaviour changes required of operators/pilots:\n  - Ensure the idle and mixture check is done within 10 hours time in service.\n  - Record the AD compliance entry in the Aircraft Log Book.\n  - Record any discrepancies in the maintenance release.\n  - Amend the POH and Pilot’s Checklist per the Cessna service bulletin.\n\nWhy the AD says it matters (and a short test of that claim)\n\n- The AD’s stated purpose is to correct an unsafe condition by ensuring correct idle speed and mixture behaviour and by updating the POH/checklist. That is the document’s explicit claim.\n\n- Costs and incentives: The technical check is short and can be done by the PIC (reduces immediate labour costs compared with requiring a licensed mechanic). If discrepancies are found, the financial cost may increase depending on the corrective work required. Amending POH/checklist imposes a minor administrative burden on owners/operators.\n\n- Trade‑offs and opportunity costs: Allowing the PIC to perform the check lowers direct compliance cost and speeds remediation, but shifts responsibility for a maintenance‑style check onto pilots (except students). Relying on an external service bulletin transfers the technical detail (and some implementation burden) to the manufacturer’s instructions.\n\n- Implementation risk and clarity: The AD is operationally specific (temperatures, RPM ranges, mixture response), so enforcement and verification are straightforward. A potential area for minor ambiguity is the interface between a PIC‑performed check and entries in the aircraft maintenance release — operators must ensure records meet regulatory maintenance‑release requirements if corrective work follows.\n\n- Effects on private choice and market actors: The AD constrains operator choices only to the extent of performing the check and amending POH/checklist within the timeframe; otherwise it leaves freedom to choose whether the PIC performs the check or a maintenance organisation is engaged.\n\nBottom line (mechanical and practical): This is a narrowly targeted airworthiness directive requiring a short, specified idle/mixture check and a POH/checklist amendment for Cessna 172R/S aeroplanes. The immediate cost and operational impact are modest: a brief check, a logbook entry, possible follow‑up maintenance if a discrepancy is found, and an administrative POH/checklist amendment following the Cessna service bulletin."},"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":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive targeting a specific technical issue with specific aircraft models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific aircraft type (Cessna 172R/S)","Two discrete requirements with clear procedural steps","Simple conditional logic (temperature range, RPM ranges)","No cross-references to other legislation beyond a single note about FAA equivalent and CAR 55(4)","Short document with minimal defined terms"],"plain_english_summary":"This Airworthiness Directive requires operators of Cessna 172R/172S aeroplanes to perform a mandated engine idle/fuel‑mixture check (to verify safe low‑power running) and to update the aircraft operating handbook/checklist per Cessna service instructions. It affects pilots (checks may be done by any pilot except students) and owners; defects must be recorded and entered in maintenance logs. Compliance mandatory from 1 Nov 2001, within 10 hours flying time."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-170-70-fuel-mixture-setting","history":"/api/acts/ad-cessna-170-70-fuel-mixture-setting/history","analysis":"/api/acts/ad-cessna-170-70-fuel-mixture-setting/analysis","conflicts":"/api/acts/ad-cessna-170-70-fuel-mixture-setting/conflicts","importantCases":"/api/acts/ad-cessna-170-70-fuel-mixture-setting/important-cases","documents":"/api/acts/ad-cessna-170-70-fuel-mixture-setting/documents"}}