{"id":"F2006B08636","name":"AD/CON/56 Amdt 1 - Number Two Crankcase Main Bearing Integrity","slug":"ad-con-56-amdt-1-number-two-crankcase-main-bearing-integrity","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51649,"registerId":"commonwealth-F2006B08636-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CON/56 Amdt 1 - Number Two Crankcase Main Bearing Integrity","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)  \nTeledyne Continental Motors Piston Engines\n\nAD/CON/56\n\nAmdt 1\n\n  \nNumber Two Crankcase Main Bearing Integrity 1/90\n\nApplicability: TSIO 520BE engines S/N 528001 through 528337 as fitted to Piper PA46-310P Malibu aircraft listed by serial number in Piper SB 913A.\n\nRequirement: 1. Inspect crankcase for end play in accordance with TCM SB M89-14 Section A,\n\n    2. Carry out thru-bolt torque check in accordance with TCM SB M89-14 Section B,\n\n    3. Inspect number two crankcase main bearing in accordance with TCM SB M89-14 Section C.\n\nNote: The repetitive checks and inspections detailed in Requirements No. 1 and No. 3 may be discontinued following disassembly of the crankcase assembly to a depth sufficient to inspect the crankcase mating flanges for evidence of fretting, and new bearings are installed.\n\nCompliance: 1. Prior to further flight and thereafter at intervals not to exceed 25 hours time in service.\n\n    2. Unless previously accomplished within 10 hours time in service prior to issue of CAO 105 AD/PA46/16; prior to further flight.\n\n    3. Prior to further flight and thereafter at intervals not to exceed 200 hours time in service.\n\nBackground: This Directive has been amended to include a terminating action. Advice from the manufacturer indicates, loss of thru-bolt torque results in fretting of the crankcase mating flanges and possible migration of the number two main bearing. Until that fretting is addressed, the integrity of the number two main bearing is suspect and repetitive inspections as detailed in TCM SB M89-14 is justified.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1731},"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The amendment adds a terminating action that allows operators to permanently satisfy the directive by disassembling the crankcase to inspect for fretting and installing new bearings, rather than requiring indefinite repetitive inspections every 25 and 200 flight hours as originally mandated."},"complexity_factors":["Mandatory compliance requires cross-referencing external technical documents (TCM SB M89-14 and Piper SB 913A) not included in the directive text","Three distinct compliance timelines with different intervals (prior to further flight, 25-hour intervals, and 200-hour intervals)","Technical aviation maintenance terminology (thru-bolt torque, fretting, crankcase mating flanges, end play)","Specific serial number applicability requiring verification against manufacturer records"],"plain_english_summary":"This safety directive applies to owners/operators of Piper Malibu PA46-310P aircraft with Teledyne Continental TSIO-520BE engines (SN 528001–528337). It addresses loose crankcase thru-bolts that can cause fretting and allow the No.2 main bearing to shift, risking catastrophic engine failure. Immediate pre-flight inspections (end play, bolt torque, bearing), recurring end-play checks every 25 flight hours and bearing inspections every 200 hours are required. Repetitive inspections may be terminated by full crankcase disassembly, fretting repair, and installation of new bearings."}},"importantCases":[],"_links":{"self":"/api/acts/ad-con-56-amdt-1-number-two-crankcase-main-bearing-integrity","history":"/api/acts/ad-con-56-amdt-1-number-two-crankcase-main-bearing-integrity/history","analysis":"/api/acts/ad-con-56-amdt-1-number-two-crankcase-main-bearing-integrity/analysis","conflicts":"/api/acts/ad-con-56-amdt-1-number-two-crankcase-main-bearing-integrity/conflicts","importantCases":"/api/acts/ad-con-56-amdt-1-number-two-crankcase-main-bearing-integrity/important-cases","documents":"/api/acts/ad-con-56-amdt-1-number-two-crankcase-main-bearing-integrity/documents"}}