{"id":"F2006B08060","name":"AD/CESSNA 208/8 - Engine Mount Ring","slug":"ad-cessna-208-8-engine-mount-ring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115150,"registerId":"commonwealth-F2006B08060-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 208/8 - Engine Mount Ring","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nCessna 208 Series Aeroplanes\n\nAD/CESSNA 208/8 Engine Mount Ring 7/90\n\nApplicability: Models 208 and 208A serial number 20800001 to 20800130.\n\n208B serial number 208B0001 to 208B0086.\n\nRequirement: 1. Visually inspect the lower portion of the engine mount ring for cracks and misalignment and:\n\n    replace any ring that is visibly misaligned or has a crack larger than 43 mm (1.7\"), or\n\n    b. where a crack is shorter than 43 mm (1.7\") repair in accordance with Model 208 Maintenance Manual P/N 02076-2-13.\n\n2. Replace nose wheel shimmy damper P/N 2643007-1 or 2 with shimmy damper P/N 2643090-1 in accordance with Cessna SB CAB88-14.\n\nNote: FAA AD 90-05-04 refers.\n\nCompliance: Within 100 hours time in service after 12 July 1990 or at the next inspection for Maintenance Release issue after 12 July 1990 whichever is the later.\n\nBackground: There have been reports of engine mount cracking that has been attributed to nose wheel shimmy. If allowed to develop the loss of mount stiffness may result in whirl mode flutter of the propeller/powerplant system. Either the cracking or the flutter could cause the engine to separate from the airframe.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific aircraft. It has not expanded beyond its original purpose of mandating inspection and repair of engine mount rings and nose wheel dampers."},"complexity_factors":["Single, specific mechanical issue addressed (engine mount cracking)","Clear applicability criteria (specific aircraft models and serial numbers)","Straightforward binary compliance path (inspect → replace if bad/repair if small crack)","Single cross-reference to FAA AD 90-05-04 (informational only)","No defined terms section, no nested exceptions, no conditional logic beyond the standard 'whichever is later' compliance timing","Total length: approximately 200 words"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of early-model Cessna 208/208A/208B aircraft to inspect the lower engine mount ring for cracks or distortion and to replace or repair it per the manual, and to fit an improved nose‑wheel shimmy damper. It addresses cracking linked to nose‑wheel vibration that can lead to severe engine whirl or even engine separation. Compliance is required within 100 flight hours after 12 July 1990 or at the next scheduled maintenance, whichever is later."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument explicitly limits applicability by serial number and prescribes inspection, repair/replacement thresholds and part swaps to address reported engine-mount cracking attributed to nose-wheel shimmy (Background). The text contains no amendment history or signals that the stated applicability or requirements have been changed from their original formulation."},"complexity_factors":["Narrow, serial-number-limited applicability requiring operators to check eligibility (Applicability).","A quantitative crack-length threshold (43 mm) that requires measurement and judgment on repair vs replacement (Requirement 1).","Repairs must follow an external maintenance manual (P/N 02076-2-13), adding dependence on manufacturer documentation (Requirement 1b).","Mandatory part-number-specific replacement of the shimmy damper and cross-reference to a Cessna service bulletin (P/N 2643090-1; SB CAB88-14) (Requirement 2).","Time-limited compliance window (within 100 hours or at next maintenance-release inspection after 12 July 1990) that constrains scheduling (Compliance).","Safety rationale links nose-wheel shimmy to engine-mount cracking and risk of engine separation, which drives the preventative nature of the directive (Background).","Reference to FAA AD creates an external compliance/compatibility reference that may require cross-jurisdictional coordination (Note)."],"plain_english_summary":"Requires owners/operators of specified Cessna 208, 208A and 208B aeroplanes (listed serial numbers) to inspect the lower engine mount ring for cracks or misalignment, repair or replace rings using a 43 mm crack-length threshold, and to replace a nose-wheel shimmy damper with a specified part per Cessna service bulletin. Work must be done within 100 flight hours or at the next maintenance‑release inspection after 12 July 1990. The rule affects aircraft operators and maintenance providers who must source parts and perform inspections/repairs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-208-8-engine-mount-ring","history":"/api/acts/ad-cessna-208-8-engine-mount-ring/history","analysis":"/api/acts/ad-cessna-208-8-engine-mount-ring/analysis","conflicts":"/api/acts/ad-cessna-208-8-engine-mount-ring/conflicts","importantCases":"/api/acts/ad-cessna-208-8-engine-mount-ring/important-cases","documents":"/api/acts/ad-cessna-208-8-engine-mount-ring/documents"}}