{"id":"F2006B11316","name":"AD/MSR/18 Amdt 2 - Engine Mount","slug":"ad-msr-18-amdt-2-engine-mount","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57170,"registerId":"commonwealth-F2006B11316-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/MSR/18 Amdt 2 - Engine Mount","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/MSR/18 Amdt 1 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.001.png)\n\nAerospatiale Rallye Series Aeroplanes\n\nAD/MSR/18\n\nAmdt 2\n\n  \n\nEngine Mount 12/2001 TX\n\nApplicability: For Requirement 1: All Model:\n\n    Rallye 180,\n    Rallye 150,\n    Rallye 110ST,\n    MS 892,\n    MS 893, and\n    MS 894 A and MS 894 E aircraft with serial numbers 1005 through 2204, except agricultural aircraft, fitted with Socata kit OPT18098 9037;\n\nequipped with engine mount part number 887.51.0.030.0, 892.51.0.033.0, 85.51.0.001.0, 892.51.0.001.0, 892.51.0.053.0, or 892.51.0.060.0.\n\nFor Requirement 2: All Model MS 893, MS 892 model A150, Rallye 150T, Rallye 150ST, and Rallye 180T aircraft equipped with engine mount part number 892.51.0.035.0.\n\nNote 1: The engine mount part number 892.51.0.035.0 may have been installed on new aircraft between 1 April 1978 and 6 November 1978, or on other aircraft by application of Socata “Information Bulletin” No. 39 and/or DGAC AD 78-149(A).\n\nRequirement: 1. Inspect the engine mount for cracks, and accomplish other actions; in accordance with Socata Service Bulletin Rallye aircraft No. 156-71.\n\nIf a crack is found, before further flight, the engine mount must be repaired or replaced. If the crack length is less than 6mm, the engine mount can be repaired in accordance with the Requirement document. If the crack length is more than 6mm the engine mount must be replaced.\n\n2. If a part number 892.51.0.035.0 engine mount is installed, replace with a different part number engine mount.\n\nAerospatiale Rallye Series Aeroplanes\n\nAD/MSR/18 Amdt 2 (Continued)\n\nNote 2: DGAC AD 2001-400(A) and AD 1978-205(A) R1 refer.\n\nCompliance: 1. At the next scheduled inspection after 3 October 2001, or before 31 October 2001, whichever occurs first. Thereafter at intervals not to exceed 50 hours time in service.\n\n2. Before further flight after 3 October 2001.\n\nThis amendment becomes effective on 3 October 2001.\n\nBackground: Cracks have been found on the engine mount.\n\nAmendment 2 is issued in response to new DGAC Airworthiness Directives which update the list of affected engine mounts, increase the frequency of repeat inspections and require the removal from service of a certain part number engine mount.\n\n![Signature of David Alan Villiers Delegate of the Civil Aviation Safety Authority](image.002.png)  \nAmendment 1 of this Airworthiness Directive became effective on 31 May 1978, The original issue of this Airworthiness Directive became effective on 31 May 1972.\n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 28 September 2001\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 3 October 2001.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 2 broadens and tightens the original AD's scope. According to the Background, this amendment updates the list of affected engine mount part numbers, increases the frequency of repeat inspections (to every 50 hours) and imposes mandatory removal from service of a particular engine mount part number (892.51.0.035.0). Compared with earlier versions (original AD in 1972 and Amendment 1 in 1978), Amendment 2 therefore expands affected parts and imposes stricter, more prescriptive maintenance and removal requirements (Applicability; Requirement 1 & 2; Compliance; Background)."},"complexity_factors":["Two distinct requirement streams (Requirement 1: inspection/repair/replace; Requirement 2: mandatory replacement for a specific part number)","Applicability split by model, serial number range (1005–2204) and exclusion (agricultural aircraft)","List of seven specific engine mount part numbers for Requirement 1 and an additional specific part number for Requirement 2","Cross-reference to an external service document (Socata Service Bulletin No. 156-71) for inspection and repair instructions","Cross-reference to foreign DGAC airworthiness directives (DGAC AD 2001-400(A) and AD 1978-205(A) R1)","A simple conditional repair/replace rule based on a single crack-length threshold (6 mm)","Fixed compliance timing conditions (initial inspection: next scheduled after 3 Oct 2001 or before 31 Oct 2001; repeat interval: every 50 hours)"],"plain_english_summary":"**What this directive does (mechanics first)**\n\n- **Requires inspections and targeted removals** of certain engine mounts on specified Aerospatiale (Socata) Rallye series aeroplanes. (Applicability; Requirement 1 & 2; Compliance.)\n- **Inspect** the engine mount for cracks in accordance with Socata Service Bulletin Rallye aircraft No. 156-71. If a crack is found: repair the mount if the crack is less than 6 mm, or replace the mount if the crack is more than 6 mm. (Requirement 1.)\n- For aircraft fitted with engine mount part number **892.51.0.035.0**, the mount **must be replaced before the next flight**. (Requirement 2; Note 1.)\n- **Timing:** carry out the initial inspection at the next scheduled inspection after 3 October 2001, or before 31 October 2001, whichever is earlier. After that, repeat inspections **every 50 hours** time in service. Replacement for PN 892.51.0.035.0 is required immediately (before further flight). (Compliance.)\n\n**Who is affected**\n\n- Owners/operators of Aerospatiale (Socata) Rallye series aeroplanes with serial numbers 1005 through 2204 (except agricultural aircraft) fitted with any of the listed engine mount part numbers: 887.51.0.030.0; 892.51.0.033.0; 85.51.0.001.0; 892.51.0.001.0; 892.51.0.053.0; 892.51.0.060.0. (Applicability for Requirement 1.)\n- A separate applicability group covers aircraft with part number **892.51.0.035.0**, which must be removed. (Applicability for Requirement 2; Note 1.)\n\n**Why the rule exists (official rationale and update)**\n\n- The directive is issued because **cracks have been found** on these engine mounts. Amendment 2 responds to new French DGAC airworthiness directives that broaden the affected mount list, increase inspection frequency and require removal of a particular mount part number. (Background; Note 2.)\n\n**Practical effects, costs and incentives**\n\n- Who pays: aircraft owners/operators pay for inspections, any repairs, and replacements (parts and labour), and they bear aircraft downtime while work is done. (Requirement; Compliance.)\n- Who decides/implements: the Civil Aviation Safety Authority (CASA) delegate issues the requirement; inspections/repairs are implemented by the operator or contracted maintenance organisations, following Socata Service Bulletin No. 156-71. (Preamble; Requirement.)\n- Behaviour change required: operators must inspect more frequently (initial inspection soon after 3 October 2001 and repeat every 50 hours) and must remove a particular mount (PN 892.51.0.035.0) immediately if fitted. (Compliance; Requirement 2.)\n- Market effects and implementation risks: the AD raises near-term demand for maintenance services and replacement mounts. If replacement parts are scarce (not stated in the AD), that could increase downtime or costs for owners. Replacing a mount rather than repairing (for cracks >6 mm or for the specified PN) shifts costs from repeated inspection/repair to one-off part replacement. These are concrete trade-offs implied by the mechanics of the requirement (Requirement; Compliance), not claims made by the AD text.\n\n**Trade-offs and compliance burden**\n\n- The directive is narrowly targeted (specific models, serial number range and part numbers), so the compliance burden is concentrated on owners/operators of those aircraft rather than the wider general aviation fleet. (Applicability.)\n- Administrative discretion is limited: the AD prescribes inspection method (Socata SB No.156-71), the crack-size threshold for repair vs replacement (6 mm), and a fixed inspection interval (50 hours). Enforcement and timing are set by the CASA delegate under the civil aviation regulations. (Requirement; Compliance; Preamble.)\n\n**Source-tested claims vs possible consequences**\n\n- The AD itself states cracks were found and that it updates earlier ADs in line with DGAC action. Those factual bases are documented in the Background and Notes. Potential consequences such as parts availability pressure, increased MRO workload, or temporary grounding are logical effects of the prescribed actions (inspection, repair, replacement) but are not asserted in the AD text; they are implementation risks and cost channels that operators and maintainers should anticipate. (Background; Requirement; Compliance.)"},"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":4,"scope_assessment":{"changed":true,"description":"This Amendment 2 significantly expanded the scope from the original 1972 directive and 1978 amendment. The background explicitly states this amendment responds to new French aviation directives that: (1) updated the list of affected engine mounts (adding new part numbers), (2) increased inspection frequency to every 50 hours (from presumably less frequent intervals), and (3) added an entirely new requirement (Requirement 2) mandating complete replacement of a specific part number that was previously only inspected. The directive evolved from a simple inspection requirement to a more complex regime with mandatory replacement for certain configurations."},"complexity_factors":["Multiple applicability sections with overlapping but distinct aircraft models and serial number ranges","Two separate requirements with different compliance timelines and actions (inspect vs. replace)","Conditional logic for crack repair thresholds (6mm distinction)","Cross-references to external documents: Socata Service Bulletin No. 156-71, DGAC AD 2001-400(A), DGAC AD 1978-205(A) R1, and Socata Information Bulletin No. 39","Nested applicability criteria combining model types, serial numbers, part numbers, and exclusions (agricultural aircraft)","Dual compliance triggers (calendar date vs. flight hours vs. scheduled inspection)"],"plain_english_summary":"This Airworthiness Directive orders owners/operators of certain Aerospatiale Rallye models with specified engine‑mount part numbers to address discovered cracking. For one group it mandates inspections per the manufacturer’s bulletin, repair if cracks <6 mm, replacement if >6 mm, and 50‑hour repeat checks; for the other group it requires immediate replacement of the specified mount before further flight. It’s required because mount failure could let an engine detach in flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-msr-18-amdt-2-engine-mount","history":"/api/acts/ad-msr-18-amdt-2-engine-mount/history","analysis":"/api/acts/ad-msr-18-amdt-2-engine-mount/analysis","conflicts":"/api/acts/ad-msr-18-amdt-2-engine-mount/conflicts","importantCases":"/api/acts/ad-msr-18-amdt-2-engine-mount/important-cases","documents":"/api/acts/ad-msr-18-amdt-2-engine-mount/documents"}}