{"id":"F2006B06546","name":"AD/RB211/16 Amdt 1 - Fuel Metering Unit - On Wing Test","slug":"ad-rb211-16-amdt-1-fuel-metering-unit-on-wing-test","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48252,"registerId":"commonwealth-F2006B06546-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RB211/16 Amdt 1 - Fuel Metering Unit - On Wing Test","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n![](image.002.png)  \nRolls Royce Turbine Engines \\- RB211 Series\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/RB211/16 and issues the following AD under subregulation 39.1 (1) of CAR 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.003.png)AD/RB211/16\n\nAmdt 1\n\n  \nFuel Metering Unit – On Wing Test 6/2001\n\nApplicability: RB211-524 engine models as detailed in Rolls Royce Service Bulletin RB.211-71- 9276 Revision 7 that do not incorporate Rolls Royce Service Bulletin RB.211-73- 9666.\n\nRequirement: Carry out fuel metering unit health checks in accordance with the procedures detailed in Rolls Royce Service Bulletin RB.211-71-9276 Revision 7.\n\nNote: The CAA (UK) has declared the requirements of NMSB RB.211.71.9276 Rev.7 to be mandatory.\n\nCompliance: As detailed in the requirement document.\n\nThis amendment becomes effective on 14 June 2001.\n\nBackground: This Directive is issued to require on-wing testing of the fuel metering unit. The Directive has been amended to reflect the manufacturer’s revision of the requirement document. The revision, in part, adds –T engines to the engine models applicable.\n\nThe original issue of this Airworthiness Directive became effective on 24 June 1993.\n\n![Signature of Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority](image.004.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 29 April 2001\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 16 May 2001.\n\nAL 6/2001\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This amendment modestly expanded the AD’s scope compared with the original 1993 AD by updating the manufacturer’s procedural reference to Rolls‑Royce SB RB.211‑71‑9276 Revision 7 and by explicitly adding the \"-T\" variants of the RB211‑524 family to the list of applicable engine models (Background). The amendment did not change the underlying safety subject (on‑wing FMU health checks) but broadened which submodels are captured and substituted a later revision of the manufacturer’s service bulletin as the compliance document."},"complexity_factors":["Short, self-contained AD text (single-page AD)","Relies on one external technical document: Rolls‑Royce SB RB.211‑71‑9276 Revision 7 (cross-reference)","Conditional applicability: applies to engines in the SB list but excludes engines incorporating SB RB.211‑73‑9666","Amendment modifies applicability by adding -T variants (minor expansion)","No internal definitions or multi‑layered exceptions beyond single exclusion clause","Compliance details (timing, procedures, work‑scope) are delegated to the external SB rather than set out in the AD"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This is an Airworthiness Directive (AD) that requires operators of certain Rolls‑Royce RB211‑524 turbofan engines to perform an on‑wing fuel metering unit (FMU) health check. (An on‑wing test is a test of the engine component while the engine remains installed on the aircraft.)\n- The AD applies to RB211‑524 engine models listed in Rolls‑Royce Service Bulletin (SB) RB.211‑71‑9276 Revision 7, except engines that already incorporate Rolls‑Royce SB RB.211‑73‑9666. (If an engine incorporates SB RB.211‑73‑9666, the AD's requirement does not apply to that engine.)\n- The required test must be carried out in the manner, and at the time, specified in Rolls‑Royce SB RB.211‑71‑9276 Revision 7; the AD makes compliance with that SB mandatory for the affected engines.\n- The AD as amended adds the “-T” variants of the RB211‑524 family to the list of applicable models and updates the reference to the manufacturer’s revised service bulletin.\n\n**Who must act and who bears the cost**\n\n- Aircraft operators or engine owners with affected RB211‑524 engines are required to arrange and pay for the on‑wing FMU health checks. That includes arranging qualified maintenance personnel and any associated downtime or support required to follow the service bulletin procedures.\n\n**Why it matters (the stated purpose and what that implies)**\n\n- The AD’s stated purpose (see \"Background\") is to require on‑wing testing of the FMU to address an unsafe condition. The manufacturer’s service bulletin contains the detailed procedures intended to detect FMU faults before they cause engine problems.\n\n**Mechanics that affect behaviour and choices**\n\n- Operators must follow an external document (Rolls‑Royce SB RB.211‑71‑9276 Rev.7) rather than internal text in the AD. That creates a direct regulatory link from CASA to the manufacturer’s maintenance procedures (Requirement; Compliance).\n- The AD excludes engines that already incorporate a particular Rolls‑Royce SB (RB.211‑73‑9666). That produces an economic signal: operators may evaluate whether adopting that SB or other modifications is preferable to repeated testing, depending on cost, downtime and operational needs (Applicability).\n\n**Costs, incentives and trade‑offs (tested against the AD’s stated goal)**\n\n- Who pays: operators/owners pay for the tests (labour, possible spare parts, and aircraft downtime). The AD itself does not provide funding or compensation (Requirement; Compliance).\n- Who decides: CASA (through its delegate) imposes the AD; the manufacturer’s service bulletin sets the step‑by‑step technical procedure. Operators decide scheduling and whether to adopt alternative SBs or modifications that change applicability.\n- Compliance burden and operational impact: the burden is operational (maintenance labour and potential aircraft out‑of‑service time) and administrative (tracking compliance, following the SB). The AD does not detail exact intervals or labour hours in the text — the SB does — so the precise burden depends on the SB instructions (Requirement; Compliance).\n- Substitution effects and incentives: because the AD exempts engines that have incorporated SB RB.211‑73‑9666, operators face a trade‑off between (a) performing the on‑wing tests required by Rev.7 and (b) incorporating RB.211‑73‑9666 (if that modification is available and acceptable), which might remove the requirement for the tests. That creates an incentive to evaluate the up‑front modification cost versus recurring testing costs.\n- Concentrated benefits and diffuse costs: the safety benefit is distributed among the operator, crew and passengers; the direct cost is concentrated on the owner/operator of affected engines. The manufacturer gains a defined role (its SB specifies the procedure), which may increase maintenance workload tied to manufacturer guidance, but the AD does not create mandatory manufacturer‑performed work.\n- Implementation risk and compliance risk: if operators do not follow the SB precisely, the intended safety mitigation may not be achieved. There is also regulatory risk for non‑compliance (enforcement under CAR Part 39). The AD depends on clear, accessible SB instructions; ambiguity in the SB increases operational risk.\n\n**Net practical effect**\n\n- A subset of RB211‑524 engines (those listed in SB RB.211‑71‑9276 Rev.7 and not modified by SB RB.211‑73‑9666) must undergo on‑wing FMU health checks per the manufacturer’s procedures. The amendment extends the applicability to additional subvariants (the “‑T” engines) and replaces the SB reference with the manufacturer’s revised document. Operators must follow the SB to remain compliant with the AD (Applicability; Requirement; Compliance; Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The original 1993 directive covered a narrower range of engine models. This 2001 amendment expands the scope to include '-T' engine variants, reflecting the manufacturer's updated technical assessment of which engines are vulnerable to the unsafe condition. The core purpose (fuel metering unit testing) remains unchanged, but the population of affected aircraft has grown."},"complexity_factors":["Short, single-purpose document (1 page)","Only 2 defined technical references (the service bulletins)","Clear three-part structure: Applicability, Requirement, Compliance","No nested exceptions or conditional logic — straightforward mandate","Heavy reliance on external technical documents (Rolls-Royce Service Bulletin) for actual procedural details","Minimal cross-referencing (only to Civil Aviation Regulations 1998, Part 39)"],"plain_english_summary":"This AD revokes and replaces AD/RB211/16 (1993), requiring operators of Rolls‑Royce RB211‑524 engines (including now −T models) to perform on‑wing health checks of fuel metering units per Service Bulletin RB.211‑71‑9276 Revision 7, excluding engines modified by SB RB.211‑73‑9666. The amendment follows the manufacturer’s update and mirrors a UK mandatory action; it aims to detect fuel‑meter faults that could cause engine failure. Effective 14 June 2001."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-rb211-16-amdt-1-fuel-metering-unit-on-wing-test","history":"/api/acts/ad-rb211-16-amdt-1-fuel-metering-unit-on-wing-test/history","analysis":"/api/acts/ad-rb211-16-amdt-1-fuel-metering-unit-on-wing-test/analysis","conflicts":"/api/acts/ad-rb211-16-amdt-1-fuel-metering-unit-on-wing-test/conflicts","importantCases":"/api/acts/ad-rb211-16-amdt-1-fuel-metering-unit-on-wing-test/important-cases","documents":"/api/acts/ad-rb211-16-amdt-1-fuel-metering-unit-on-wing-test/documents"}}