{"id":"F2006B06540","name":"AD/RB211/1 Amdt 4 - A.V.M. Indication and Oil Pressure Indication and M.E.L.Requirements, Procedures","slug":"ad-rb211-1-amdt-4-a-v-m-indication-and-oil-pressure-indication-and-m-e-l-requirements-procedures","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48224,"registerId":"commonwealth-F2006B06540-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RB211/1 Amdt 4 - A.V.M. Indication and Oil Pressure Indication and M.E.L.Requirements, Procedures","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)  \nRolls Royce Turbine Engines \\- RB211 Series\n\nAD/RB211/1\n\nAmdt 4\n\n  \n\nA.V.M. Indication and Oil Pressure Indication and M.E.L.Requirements, Procedures\n\n  \n4/94\n\nApplicability: RB211-524D4-19 series engines.\n\nRequirement: Part 1. For aircraft that have been modified to incorporate Rolls Royce SB RB211-72-7836 and Vibro Meter SB RB211-77-002 fitted on Boeing 747 aircraft, action in accordance with Rolls Royce SB RB211-77-A9663.\n\nNote: UK CAA AD No. 015-10-93 refers.\n\nPart 2. For aircraft not modified as in part 1, action in accordance with Rolls Royce SB RB211-77-A8446.\n\nNote: UK CAA AD No. 005-05-88 refers.\n\nCompliance: With effect from 18 April 1994.\n\nBackground: Part 1. SB RB211-77-A9663 outlines updated conditional alternative operating procedures in the event of an Airborne Vibration Monitoring (AVM) system warning. The modifications introduced by SB RB211-72-7836 have proven to be successful in slowing the rate of failure progression following the failure of the location bearings. As such, there is now time to interrogate the AVM system to confirm if the warning is genuine. This will in turn reduce the number of unnecessary engine shut-downs.\n\nPart 2. For aircraft that have not incorporated SB RB211-72-7836, the operating procedures covered by Rolls Royce SB RB211-77-A8446 are still mandatory.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This directive maintains its original narrow scope — prescribing specific operational procedures for AVM and oil pressure indication on one engine series. It has not expanded beyond its initial safety purpose."},"complexity_factors":["Short, single-purpose directive (approximately 250 words)","Only 2 defined scenarios (modified vs unmodified aircraft)","Minimal cross-referencing — references 4 external service bulletins and 2 UK CAA directives but does not incorporate their text","No nested conditional logic or exceptions to exceptions","Clear binary applicability test (presence or absence of specific modifications)","Single compliance date with no phased implementation"],"plain_english_summary":"This CASA Airworthiness Directive mandates different engine‑handling procedures for Rolls‑Royce RB211‑524D4‑19 engines on Boeing 747s depending on whether specific Rolls‑Royce and Vibro Meter service bulletin modifications are installed. Modified engines may use updated procedures that let crews verify vibration warnings before shutdown, reducing unnecessary engine shutdowns; unmodified engines must keep the older, stricter actions. It affects operators and maintenance staff and has been mandatory since 18 April 1994."},"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive modifies the operational scope for modified engines by permitting a new conditional interrogation procedure (per Rolls‑Royce SB RB211-77-A9663) instead of the previously mandatory action; for unmodified engines the original mandatory procedure (per SB RB211-77-A8446) remains in force. In effect, it relaxes the mandatory shut‑down response for engines fitted with the specified modification while keeping the earlier requirements for others."},"complexity_factors":["Limited applicability: only RB211-524D4-19 series engines are affected.","Two alternative compliance tracks depending on whether specific modifications/service bulletins (SB RB211-72-7836, Vibro Meter SB RB211-77-002) are fitted.","Direct reliance on manufacturer service bulletins (RB211-77-A9663 and RB211-77-A8446) to set procedural detail rather than full procedural text in the AD.","Cross-reference to external regulator material (UK CAA AD numbers) increases traceability requirements for operators.","Operational change (crew interrogation of AVM warnings) imposes procedural and training implications for flight crews and maintenance organisations.","Fixed compliance date: operators must be compliant by 18 April 1994 (administrative enforcement point)."],"plain_english_summary":"This airworthiness directive requires operators of RB211-524D4-19 engines to follow revised procedures for responding to Airborne Vibration Monitoring (AVM) warnings and oil pressure indications. Aircraft modified with the named Rolls‑Royce and Vibro Meter service bulletins may use an updated conditional interrogation procedure; aircraft not modified must continue to use the earlier mandatory procedure. The stated aim is to reduce unnecessary engine shut‑downs by allowing crews more time to confirm whether an AVM warning is genuine when bearing‑failure progression is slowed."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rb211-1-amdt-4-a-v-m-indication-and-oil-pressure-indication-and-m-e-l-requirements-procedures","history":"/api/acts/ad-rb211-1-amdt-4-a-v-m-indication-and-oil-pressure-indication-and-m-e-l-requirements-procedures/history","analysis":"/api/acts/ad-rb211-1-amdt-4-a-v-m-indication-and-oil-pressure-indication-and-m-e-l-requirements-procedures/analysis","conflicts":"/api/acts/ad-rb211-1-amdt-4-a-v-m-indication-and-oil-pressure-indication-and-m-e-l-requirements-procedures/conflicts","importantCases":"/api/acts/ad-rb211-1-amdt-4-a-v-m-indication-and-oil-pressure-indication-and-m-e-l-requirements-procedures/important-cases","documents":"/api/acts/ad-rb211-1-amdt-4-a-v-m-indication-and-oil-pressure-indication-and-m-e-l-requirements-procedures/documents"}}