{"id":"F2006B10040","name":"AD/G1159/37 - Wing Plank Splice Between BL 135 and BL 156","slug":"ad-g1159-37-wing-plank-splice-between-bl-135-and-bl-156","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55457,"registerId":"commonwealth-F2006B10040-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/G1159/37 - Wing Plank Splice Between BL 135 and BL 156","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)  \nGulfstream (Grumman) G1159 and G-IV Series Aeroplanes\n\nAD/G1159/37 Wing Plank Splice Between BL 135 and BL 156 9/94\n\nApplicability: All model GII, GIIB and GIII aircraft.\n\nRequirement: Inspect the wing plank splice fail-safe channels and splice fittings on the lower middle and aft wing plank splices between BL 135 and BL 156, to detect cracks, in accordance with Gulfstream Customer Bulletin (GCB) 400A for GII aircraft, GCB 403A for GIIB aircraft, or GCB 114A for GIII aircraft.\n\nNote: FAA AD 93-01-18 refers.\n\nCompliance: Unless previously accomplished, inspect within 150 flight hours or 90 days from 18 August 1994, whichever occurs first.\n\nFor those aircraft found to have cracks which are within the limits and conditions specified by the applicable GCB, re-inspect at intervals not to exceed 6 months, until repaired or replaced. Repair or replacement must be completed no later than the next regularly scheduled 18-month wing tank interior inspection.\n\nThereafter, inspect in accordance with the Maintenance Manual requirements for this area.\n\nBackground: This AD is prompted by reports of cracks in the fail safe channels and splice fittings of several GII and GIII aircraft, which extend beyond the limits of detection of the inspection method specified in the original issue of the Gulfstream Customer Bulletin applicable to each model aircraft. This AD mandates the Gulfstream requirement for an additional eddy current inspection to be performed if cracks are found using the original ultrasonic inspection.","sortOrder":0}],"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":true,"description":"Expands the original inspection regime by mandating an additional eddy‑current inspection when the original ultrasonic check shows cracks, thereby extending detection methods beyond those in the initial Gulfstream Bulletins. It also prescribes firm compliance timeframes, six‑month reinspection intervals for allowable cracks, and a repair/replacement deadline tied to the 18‑month wing tank interior inspection."},"complexity_factors":["Technical inspection methods required: initial ultrasonic inspection with mandatory follow-up eddy‑current inspection if cracks are detected (adds procedural/skill requirements).","Cross-references to model-specific Gulfstream Customer Bulletins (GCB 400A/403A/114A) and FAA AD 93-01-18 increase document reliance and interpretation work.","Time-bound compliance windows (150 flight hours or 90 days) and recurring inspection intervals (every 6 months) impose scheduling and operational constraints.","Repair/replacement deadline tied to the next scheduled 18‑month wing tank interior inspection creates a compliance milestone linked to existing maintenance cycles.","Applicability limited to specific models but covers multiple related airframe zones (lower middle and aft wing plank splices between BL 135–156), requiring targeted structural inspections."],"plain_english_summary":"Requires owners/operators of Gulfstream GII, GIIB and GIII aeroplanes to inspect the wing plank splice fail‑safe channels and splice fittings between buttlines (BL) 135 and 156 for cracks, following the applicable Gulfstream Customer Bulletin. Inspections must be done within 150 flight hours or 90 days; if ultrasonic inspection finds cracks, an additional eddy‑current check and recurring six‑month re‑inspections are mandated until repair or replacement is completed (repair due by the next 18‑month wing tank interior inspection)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific structural defect in specific Gulfstream aircraft models. It has not expanded beyond its original safety purpose of detecting and managing cracks in wing plank splices."},"complexity_factors":["Single, specific technical requirement focused on one aircraft component","Clear applicability clause limiting scope to three specific aircraft models","Straightforward compliance timeline (150 flight hours or 90 days)","Conditional logic limited to two scenarios: cracked vs. uncracked findings","References external technical documents (Gulfstream Customer Bulletins) but provides specific document numbers for each aircraft variant","No nested definitions or extensive interpretation sections","Single cross-reference to corresponding FAA directive for context"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections of the wing plank splice (BL 135–BL 156) on Gulfstream GII, GIIB and GIII jets after cracks were found in channels and fittings. Operators must perform an initial check within 150 flight hours or 90 days from 18 Aug 1994; detected cracks require eddy‑current follow‑up and six‑monthly re‑inspections until repaired, with repairs due by the next 18‑month wing tank inspection. It affects Australian owners/operators of these Gulfstream models."}},"importantCases":[],"_links":{"self":"/api/acts/ad-g1159-37-wing-plank-splice-between-bl-135-and-bl-156","history":"/api/acts/ad-g1159-37-wing-plank-splice-between-bl-135-and-bl-156/history","analysis":"/api/acts/ad-g1159-37-wing-plank-splice-between-bl-135-and-bl-156/analysis","conflicts":"/api/acts/ad-g1159-37-wing-plank-splice-between-bl-135-and-bl-156/conflicts","importantCases":"/api/acts/ad-g1159-37-wing-plank-splice-between-bl-135-and-bl-156/important-cases","documents":"/api/acts/ad-g1159-37-wing-plank-splice-between-bl-135-and-bl-156/documents"}}