{"id":"F2006B03243","name":"AD/B747/63 - APU Fuel Drain System","slug":"ad-b747-63-apu-fuel-drain-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42667,"registerId":"commonwealth-F2006B03243-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/63 - APU Fuel Drain System","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)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/63 APU Fuel Drain System 6/88\n\nApplicability: B747 aeroplanes line numbers:\n\ni) 1-153, 156 and 157 on which Boeing SB 747-49-2021 has been incorporated, and\n\nii) 154, 155, 158-678, 680 and 682-684.\n\nRequirement: 1. Inspect the APU fuel supply line for leaks in accordance with Boeing 747 Maintenance Manual Section 28-25-00 page 601, dated 25 August 1987.\n\n2. Modify the APU fuel line drain system, fuel pump drain, and turbine drain assembly in accordance with Boeing Service Bulletin 747-49-2051 dated 5 November 1987.\n\nNote: FAA AD 88-05-07 Amdt 39-5867 refers.\n\nCompliance: 1. Unless already accomplished, within 30 days after 16 June 1988 and thereafter at intervals not to exceed 30 days until modified in accordance with Para 2 of the Requirement. If leakage is detected, rectify before further flight.\n\n2. Prior to 31 December 1990.\n\nNote: Modification iaw SB 747-49-2051 constitutes terminating action for the repetitive inspection requirements.\n\nBackground: An overseas operator has reported finding fuel in the forward cargo compartment and in several of the overwing floor beam bays. The fuel originated from a leak in the APU engine fuel pump seal which pressurized the fuel line shroud and passed into the aircraft through an improperly installed coupling on the shroud. This Directive has been issued to eliminate a potential fire hazard.","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 eliminating the APU fuel leak fire hazard."},"complexity_factors":["Very short document (under 300 words)","Only 2 main requirements with clear deadlines","Limited applicability (specific Boeing 747 line numbers listed explicitly)","Single cross-reference to FAA AD 88-05-07 for context only","No nested definitions or conditional exceptions","Clear terminating action (modification ends inspection requirement)"],"plain_english_summary":"This CASA Airworthiness Directive mandates recurring 30‑day inspections for fuel leaks from the APU fuel supply line on certain Boeing 747s, and requires a permanent modification of the APU fuel drain system by the end of 1990 per Boeing instructions. \n\nIt responds to a discovered fuel leak through a faulty APU pump seal and coupling that created a serious fire risk, and affects owners/operators of the specified 747 serial numbers."},"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive addresses a specific safety issue reported by an operator (fuel ingress from an APU fuel pump seal leak) and targets the APU fuel drain system on specified B747 line numbers to remove the fire hazard (Background; Applicability; Requirement). There is no text in the instrument expanding scope beyond correcting that fault pattern; measures are inspection until modification and a final mandated modification (Compliance)."},"complexity_factors":["Technical remediation delegated to a manufacturer service bulletin with specific hardware changes (Requirement; Boeing SB 747-49-2051).","Applicability limited to a defined set of airframe line numbers, requiring fleet-level tracking (Applicability).","Short, repeating inspection cycle (every 30 days) until modification imposes recurring operational and maintenance burden (Compliance para 1).","Hard compliance deadline for modification (31 December 1990) creates scheduling pressure (Compliance para 2).","Immediate operational constraint: detected leaks must be rectified before further flight, potentially causing AOG/grounding (Compliance para 1).","Terminating action tied to completion of modification rather than alternative mitigations (Compliance Note).","Reference to FAA AD creates cross-jurisdictional regulatory alignment considerations (Note)."],"plain_english_summary":"_This Airworthiness Directive orders operators of the listed Boeing 747 airframes to inspect the APU fuel supply line for leaks every 30 days until they complete a mandated modification of the APU fuel drain, pump drain and turbine drain assemblies per Boeing Service Bulletin 747-49-2051, with that modification required by 31 December 1990 (Applicability; Requirement; Compliance)._ Operators must fix any leak before further flight; carrying out the modification ends the recurring inspections (Compliance; Note)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-63-apu-fuel-drain-system","history":"/api/acts/ad-b747-63-apu-fuel-drain-system/history","analysis":"/api/acts/ad-b747-63-apu-fuel-drain-system/analysis","conflicts":"/api/acts/ad-b747-63-apu-fuel-drain-system/conflicts","importantCases":"/api/acts/ad-b747-63-apu-fuel-drain-system/important-cases","documents":"/api/acts/ad-b747-63-apu-fuel-drain-system/documents"}}