{"id":"F2006B03202","name":"AD/B747/309 - Electrical Bonding","slug":"ad-b747-309-electrical-bonding","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42574,"registerId":"commonwealth-F2006B03202-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nBoeing 747 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B747/309 Electrical Bonding 8/2004","sectionType":"part","heading":"AD/B747/309 Electrical Bonding 8/2004","content":"# AD/B747/309 Electrical Bonding 8/2004\n\nApplicability: Model 747 series aeroplanes with line numbers 1 through 1271 inclusive.\n\nRequirement: 1. Prepare the electrical bonding faying surfaces for the tubing penetrations of the hydraulic heat exchanger on the forward and aft surfaces of the rear spars of the fuel tanks of the left and right wings, together with carrying out a one-time measurement of the electrical bonding resistances between the penetration fittings of the hydraulic heat exchanger and the rear spars; and between the heat exchanger tube and the lower wing stringer surfaces, per the Accomplishment Instructions of ASB 747-29A2104 Revision 1 dated 7 March 2002.\n\n    2. If the bonding resistance is incorrect, repeat the preparation of the electrical bonding faying surface for the tubing penetrations of the hydraulic heat exchanger on the forward and aft surfaces of the rear spar of the fuel tanks of the left and right wings as necessary to achieve a bonding resistance below the threshold specified in the Accomplishment Instructions of ASB 747-29A2104 Revision 1.\n\n    3. Apply fillet sealant and protective finishes around the penetration fittings of the hydraulic heat exchanger in accordance with the Accomplishment Instructions of ASB 747-29A2104 Revision 1 (Figure 4 refers).\n\n    4. Service and pressurize the hydraulic systems and examine for signs of hydraulic fluid leakage. Service the fuel tank and examine for signs of fuel leakage. All these actions are to be accomplished in accordance with ASB 747-29A2104 Revision 1.\n\n    5. Repair any leaks found, during the Requirement 4 examination, in accordance with ASB 747-29A2104 Revision 1.\n\nActions accomplished before the effective date of this Directive in accordance with Boeing ASB 747-29A2104, dated 19 July 2001, are considered acceptable for compliance with the corresponding action specified in this Directive.\n\nNote: FAA AD 2004-10-06 Amdt 39-13636 refers.\n\nCompliance: For Requirement 1 \\- Within 60 months after the effective date of this Directive.","sortOrder":1}],"analysis":{"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":"This AD implements inspection, measurement and repair steps specified in Boeing ASB 747-29A2104 Rev 1 for 747 line numbers 1–1271, accepts prior actions done under the earlier ASB dated 19 July 2001, and sets a 60‑month compliance timeframe. It does not broaden applicability or add requirements beyond the ASB and referenced FAA AD."},"complexity_factors":["Technical procedures require specialised maintenance skills to prepare bonding surfaces and measure electrical resistance (Requirement 1–2).","The AD depends on external instructions and thresholds in Boeing ASB 747-29A2104 Rev 1 (Requirement, Note).","Repeat work until resistance falls below the ASB threshold creates potential for variable labour/time per aircraft (Requirement 2).","Requires coordination of hydraulic and fuel system servicing and pressurisation for leak checks, with attendant safety controls (Requirement 4–5).","Applicability is limited by line numbers, requiring fleet tracking to determine affected aircraft (Applicability).","Acceptance of prior compliance under an earlier ASB date introduces record-keeping and verification tasks (paragraph on actions accomplished before effective date)."],"plain_english_summary":"**What this does.** This Airworthiness Directive requires operators of Boeing 747 aeroplanes (line numbers 1–1271) to prepare and verify electrical bonding at hydraulic heat‑exchanger tube penetrations on wing rear spars, measure bonding resistance, rework until resistance meets the Boeing ASB threshold, apply sealant/finishes, pressurise and inspect hydraulic and fuel systems, and repair any leaks, following Boeing ASB 747‑29A2104 Rev 1 (Requirement 1–5).\n\n**Who pays and who decides.** Aircraft operators pay for the inspections and repairs; CASA issues the AD and enforces a 60‑month compliance window for Requirement 1 (Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused, targeted scope. It addresses a specific unsafe condition (electrical bonding in fuel tank penetrations) for a defined aircraft population. There is no evidence of scope creep; the directive remains tightly bounded to its original safety purpose."},"complexity_factors":["Technical aviation terminology throughout (e.g., \"faying surfaces,\" \"fillet sealant,\" \"stringer surfaces,\" \"ASB\" [Alert Service Bulletin])","Multiple cross-references to external Boeing technical documents (ASB 747-29A2104 Revision 1) without reproducing those instructions in the directive itself","Conditional logic in Requirement 2 (\"If the bonding resistance is incorrect, repeat...\") creating a loop until compliance is achieved","Nested action structure: Requirement 4 requires examination, Requirement 5 requires repair of anything found in Requirement 4","Specific manufacturing range applicability (line numbers 1-1271) requiring operators to check aircraft records","Grandfathering clause for actions taken under earlier version of Boeing bulletin (July 2001 vs March 2002)"],"plain_english_summary":"This CASA safety order requires operators of most Boeing 747s (line numbers 1–1271) to inspect and, if necessary, repair electrical bonding of hydraulic heat‑exchanger tubes that pass through fuel tank walls. Within 60 months, operators must clean contact surfaces, measure and restore bonding, apply sealant/coatings, and pressure‑test systems to prevent sparks or static near fuel vapours — reducing the risk of in‑flight fuel‑tank ignition or explosion."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-309-electrical-bonding","history":"/api/acts/ad-b747-309-electrical-bonding/history","analysis":"/api/acts/ad-b747-309-electrical-bonding/analysis","conflicts":"/api/acts/ad-b747-309-electrical-bonding/conflicts","importantCases":"/api/acts/ad-b747-309-electrical-bonding/important-cases","documents":"/api/acts/ad-b747-309-electrical-bonding/documents"}}