{"id":"F2020L01124","name":"AD/GC-1/6 Engine Mount","slug":"ad-gc-1-6-engine-mount","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":113540,"registerId":"commonwealth-F2020L01124-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Swift Museum Foundation GC-1A and GC-1B ","sectionType":"part","heading":"Swift Museum Foundation GC-1A and GC-1B Series Aeroplanes","content":"# Swift Museum Foundation GC-1A and GC-1B Series Aeroplanes\n\n| AD/GC-1/6 | Engine Mount | 18/2020 |\n| --------- | ------------ | ------- |\n\n| Applicability: | Swift Museum Foundation GC-1B model aircraft with standard engine mount Part Number 11-710-2520. |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. (a) Examine the engine mount members for evidence of rust and/or \"pin holing\" by probing with an ice pick or an equivalent tool.If the tubular member appears solid from the inspection described in 1.(a), remove the upper drive screw present in most engine mount legs, or drill a No. 37 size hole at this upper end of the engine mount member. Drill another No. 37 hole at the lower end of the member and check for the presence of rust, water or deterioration.(b) Replace any engine mount member that has been found to be damaged from internal corrosion by welding in a new member of 7/8 x 0.035 inch 4130 steel heat treated to 85,000 p.s.i. yield. Drill No. 37 holes in each end of this new member. Fill any new or existing member with Lionoil (or equivalent slushing compound) and then drain. The No. 37 holes can be used for this purpose. After the slushing compound has been drained out of the member, plug the holes with drive screws, AN 535-4-3.Note 1: No exact method exists in the field for measuring the wall thickness remaining at the lower end of the tube, or of determining the exact amount of wall deterioration through rusting, but a close visual inspection of the drilled hole coupled with the condition encountered (i.e., obvious presence of water or rust) will allow a reasonable judgment of the general condition. For example, after the hole is drilled, the presence of a heavy colloidal solution of rust in water would indicate the probability of serious deterioration. An air nozzle may be applied at the upper hole to facilitate the expelling of any moisture that may be present.Note 2: United States of America Federal Aviation Administration (FAA) AD 64‑05‑06 is the source document for the requirements of this AD. |\n| Compliance: | 1. Unless previously accomplished, within 6 months after the commencement date of this AD and thereafter at each 100 hours’ time in service or every 12 months, whichever occurs first. |\n| | This AD commences on 17 September 2020. |\n\n| Background: | There have been instances of failure through internal corrosion of the upper left and right hand members of the engine mount assembly, the point of failure being just above the weld junction with the horizontal members of the engine mount. This AD is issued to preclude the possibility of failures on Australian registered aircraft, which could result in the loss of the engine.An audit of the Australian Aircraft Register found that Swift Museum Foundation GC-1B aircraft have been on the register for some time and that requirements equivalent to the applicable FAA ADs have not previously been mandated in Australia for these aircraft.This AD mandates requirements equivalent to FAA AD 64-05-06. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![A drawing of a face\nDescription automatically generated](image.001.jpeg)\n\nPieter van Dijk \nDelegate of the Civil Aviation Safety Authority\n\n25 August 2020","sortOrder":0},{"sectionNumber":"AD/GC-1/6","sectionType":"part","heading":"AD/GC-1/6","content":"## AD/GC-1/6","sortOrder":1},{"sectionNumber":"Engine Mount","sectionType":"part","heading":"Engine Mount","content":"## Engine Mount","sortOrder":2},{"sectionNumber":"18/2020","sectionType":"part","heading":"18/2020","content":"## 18/2020","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"This AD adopts requirements equivalent to FAA AD 64‑05‑06 and applies to Swift Museum Foundation GC‑1B aircraft fitted with engine mount Part No. 11‑710‑2520. It does not broaden the applicability beyond that FAA‑equivalent scope; rather it mandates those checks and repairs for Australian‑registered aircraft because they had not previously been mandated here."},"complexity_factors":["Technical inspection method requires probing with an ice pick or equivalent and drilling No. 37 holes (Requirement 1(a)).","Repair requires replacement members welded in to a precise material and dimension spec: 7/8 x 0.035 inch 4130 steel heat treated to 85,000 p.s.i. yield (Requirement 1(b)).","Recurring compliance schedule: within 6 months, then every 100 hours TIS or 12 months, whichever first (Compliance).","Use of slushing compound (Lionoil or equivalent) to fill and drain members and then plug with specified drive screws AN 535-4-3 (Requirement 1(b)).","Field measurement uncertainty: Note 1 states no exact field method for wall‑thickness measurement; inspectors must make judgement calls based on drilled‑hole appearance and presence of rust/water (Note 1).","Cross‑reference to FAA AD 64‑05‑06 as the source document (Note 2) — requires implementers to align with an external AD.","Need for skilled work (precision drilling, welding to material and heat‑treat spec, sealing) and access to specific parts/tools (No. 37 drill, AN 535-4-3 drive screws).","Potential operational disruption and cost: parts, skilled labour, and aircraft downtime for initial and recurring actions.","Limited diagnostic access: drilling to inspect risks further corrosion exposure and requires repair if deterioration found (trade‑off between inspection invasiveness and detection)."],"plain_english_summary":"**What this does.** This airworthiness directive requires owners/operators of Swift Museum Foundation GC‑1B aeroplanes fitted with standard engine mount Part No. 11‑710‑2520 to inspect the upper engine‑mount tubes for internal corrosion or 'pin‑holing', drill/check access holes, replace any corroded members with specified 4130 steel replacements, fill and drain a slushing compound, and plug the holes.\n\n**Who pays and why it matters.** Compliance (inspection, possible replacement, parts and labour) is mandatory within 6 months and then every 100 flight hours or 12 months to reduce the risk of engine separation caused by internal corrosion."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope. It targets a specific safety issue (engine mount corrosion) in a specific aircraft type (Swift GC-1B) with a specific part number. The document explicitly states it is adopting equivalent requirements to an existing FAA directive, indicating no scope creep from the original safety intent."},"complexity_factors":["Single, specific applicability criterion (one aircraft model with one specific part number)","Straightforward two-step requirement: inspect, then repair/replace if needed","Clear compliance deadline (6 months from commencement, then recurring intervals)","Contains practical field guidance (Note 1 on visual inspection judgment, Note 2 on source document)","Technical specifications provided (material dimensions, drill sizes, part numbers for plugs)","Limited cross-referencing (only to FAA AD 64-05-06 as source document)","No nested exceptions or conditional logic chains","Short document length with single purpose"],"plain_english_summary":"This AD mandates inspections and ongoing checks of engine mounts on Australian‑registered Swift Museum Foundation GC‑1B aircraft with engine mount P/N 11‑710‑2520, requiring replacement of any members showing internal corrosion (pin‑holing) and treatment of new tubing. It affects owners, operators and maintenance organisations and addresses prior in‑service failures where corroded mount members led to engine separation, closing a safety gap with U.S. requirements."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gc-1-6-engine-mount","history":"/api/acts/ad-gc-1-6-engine-mount/history","analysis":"/api/acts/ad-gc-1-6-engine-mount/analysis","conflicts":"/api/acts/ad-gc-1-6-engine-mount/conflicts","importantCases":"/api/acts/ad-gc-1-6-engine-mount/important-cases","documents":"/api/acts/ad-gc-1-6-engine-mount/documents"}}