{"id":"F2006B09862","name":"AD/F50/36 - Alternate Brake System Cables","slug":"ad-f50-36-alternate-brake-system-cables","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54953,"registerId":"commonwealth-F2006B09862-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/36 - Alternate Brake System Cables","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)  \nFokker F50 (F27 Mk 50) Series Aeroplanes\n\nAD/F50/36 Alternate Brake System Cables 9/90\n\nApplicability: F27 Mark 50 aircraft with S/Nos 20103 through 20181. Requirement: Action in accordance with Fokker SB F50-32-006 Rev 1.\n\nNote 1: RLD BLA 89-063 Issue 2 refers.\n\nNote 2: Compliance with Part 2 of the Requirement document is considered terminating action for this Directive.\n\nCompliance: Unless already carried out in the 900 hours time in service prior to 6 September 1990\n\n\\- Prior to exceeding 100 hours time in service after 6 September 1990 or at the next scheduled inspection for issue of Maintenance Release after 6 September 1990, whichever occurs later, and thereafter at intervals not exceeding 1000 hours time in service, until terminating action is carried out.\n\nBackground: Country of origin AD. Excessive cable wear has been experienced which is attributed to a too small pulley radius, cable vibrations and perhaps more frequent use of alternate brakes. Terminating action replaces pulleys.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with narrow, targeted scope. It addresses a specific mechanical defect in a specific aircraft model and does not appear to have expanded beyond its original safety purpose."},"complexity_factors":["Single specific aircraft type and narrow serial number range (20103-20181)","Only one substantive requirement: follow Fokker Service Bulletin F50-32-006 Rev 1","Simple compliance timeline: 100 hours after September 1990, then every 1000 hours","Minimal cross-referencing (one service bulletin, one reference to another airworthiness directive)","No defined terms section, no conditional logic beyond the applicability criteria","Clear terminating action specified (Part 2 of the requirement document)"],"plain_english_summary":"This safety directive requires owners/operators and maintenance engineers of Fokker F50 aircraft (S/N 20103–20181) to inspect alternate brake-system cables regularly because undersized pulleys are causing accelerated wear. Inspections occur every 1,000 flight-hours (with an initial earlier check), and replacing the small pulleys with correctly sized parts is the terminating action.\n\nCASA enforces compliance to prevent cable failure that could lead to loss of braking during landing or taxi."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive's scope is consistent with its stated aim in the source: addressing excessive wear on alternate brake cables for the listed F27 Mk 50 serial numbers by mandating inspections and eventual pulley replacement. No expansion or narrowing of applicability is indicated in the text provided."},"complexity_factors":["Narrow applicability limited to specific serial numbers (Applicability)","Mandated compliance by reference to an external service bulletin (Requirement)","Two-tiered compliance timing: near-term mandatory check plus recurring inspections until terminating action (Compliance)","Terminating action specified (pulley replacement) changes inspection obligation once completed (Requirement/Background)","Cross-reference to another document (RLD BLA 89-063) increases document tracking","Operational impact tied to maintenance release scheduling and parts availability (Compliance/Requirement)"],"plain_english_summary":"**What it does:** Requires operators of Fokker F27 Mark 50 aeroplanes (serial nos. 20103–20181) to inspect and, where necessary, modify alternate brake system cables in accordance with Fokker Service Bulletin F50‑32‑006 Rev 1. **Who it affects and why it matters:** Aircraft operators pay for inspections, recurrent checks and any pulley replacement specified as terminating action; the measure responds to reported excessive cable wear attributed to small pulley radii and vibration. (See Applicability; Requirement; Compliance; Background.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-36-alternate-brake-system-cables","history":"/api/acts/ad-f50-36-alternate-brake-system-cables/history","analysis":"/api/acts/ad-f50-36-alternate-brake-system-cables/analysis","conflicts":"/api/acts/ad-f50-36-alternate-brake-system-cables/conflicts","importantCases":"/api/acts/ad-f50-36-alternate-brake-system-cables/important-cases","documents":"/api/acts/ad-f50-36-alternate-brake-system-cables/documents"}}