{"id":"F2006B02183","name":"AD/AC-112/13 Amdt 2 - Wing Forward Spar","slug":"ad-ac-112-13-amdt-2-wing-forward-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41413,"registerId":"commonwealth-F2006B02183-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC-112/13 Amdt 2 - Wing Forward Spar","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 (Rockwell) 112 Series Aeroplanes\n\nAD/AC-112/13\n\nAmdt 2\n\n  \nWing Forward Spar 6/95\n\nApplicability: Models 112 and 112B with serial numbers 1 to 544 and 13000, and models 112TC and 112TCA with serial numbers 13001 to 13309, not modified on both left and right hand sides in accordance with Gulfstream Aerospace Service Bulletin 112-71C Part II, Part III, Part IV or Part V.\n\nRequirement: 1. Visually inspect, using a mirror or borescope, the upper cap of the forward wing spar in the area of the main landing gear side brace fitting. Inspect in accordance with the instructions specified in Part I of Gulfstream Aerospace Service Bulletin 112-71C.\n\n    2.a. For aircraft not previously modified in accordance with either Part II or Part V of Gulfstream Aerospace SB 112-71, -71A or 71B, modify in accordance with Part II of Gulfstream Aerospace Service Bulletin 112-71C, or\n\n    2.b. For aircraft previously modified in accordance with either Parts II or Part V of Gulfstream Aerospace Service Bulletin 112-71, -71A or -71B, modify in accordance with Part III of Gulfstream Aerospace Service Bulletin 112-71C.\n\nNote: FAA AD 90-04-07 refers and supersedes FAA AD 87-14-03.\n\nCompliance: 1. Initially inspect in accordance with Requirement 1 within 25 hours’ time in service from 25 May 1995.\n\nRe-inspect at intervals not to exceed 100 hours’ time in service.\n\n2. Modify in accordance with Requirement 2 within 300 hours’ time in service from 25 May 1995.\n\nAircraft modified in accordance with Gulfstream Aerospace Service Bulletin 112-71, 112-71A or 112-71B or Drawing 40002 RWK #1, #2, #4G, #4H or 42000 RWK #3\n\nare only in partial compliance with this AD and require further inspection and modification.\n\nBackground: There have been several Australian reports of cracking similar to that described in the Gulfstream SB.. The FAA have determined that the earlier modifications are inadequate as a permanent solution to the problem. This Amendment introduces the latest Revision of the SB, which requires a more extensive modification.","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":"This Amendment expands the obligations compared with earlier iterations by introducing the latest revision of Gulfstream SB 112-71C, which requires a more extensive structural modification than earlier SB revisions. The background explains that earlier modifications (under Gulfstream SB 112-71, 112-71A, 112-71B or certain drawings) were judged inadequate and are treated as only partial compliance; such aircraft must undergo additional inspection and further modification (Requirement 2.b and the Compliance note). Mechanically, the scope has shifted from interim inspection and limited earlier fixes to mandatory rework according to the more extensive SB revision and continued interim inspections until that rework is completed."},"complexity_factors":["Limited length (short AD text)","Specific applicability with serial-number ranges and an exception (excluded where both sides already modified)","Two-step requirements: inspection (Part I of SB) and conditional modification (Requirement 2.a or 2.b)","Cross-references to multiple external documents: Gulfstream SB 112-71C (Parts I–V), earlier SBs (112-71, 112-71A, 112-71B), FAA ADs and various drawings","Time-based compliance deadlines tied to a fixed reference date (25 May 1995) with short intervals (25, 100, 300 hours)","A note creating partial-compliance statuses for aircraft previously modified (adds conditional logic)"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Applies to Gulfstream (Rockwell) Model 112 and 112B (serials 1–544 and 13000) and Models 112TC and 112TCA (serials 13001–13309) except where both left and right forward wing spars have already been modified in accordance with specified Gulfstream Service Bulletin (SB) parts. (See \"Applicability\".)\n\n- Requires an initial **visual inspection** (using a mirror or borescope) of the **upper cap of the forward wing spar** at the main landing gear side brace fitting, following the instructions in Part I of Gulfstream SB 112-71C. (See \"Requirement 1\".)\n\n- Requires a **repeated inspection** at intervals not exceeding **100 flight hours**. (See \"Compliance\" for intervals.)\n\n- Requires a **permanent modification** of the forward wing spar structure:\n  - If the aircraft has not previously been modified under Part II or Part V of earlier Gulfstream SBs, the operator must carry out the modification in accordance with **Part II of Gulfstream SB 112-71C**. (Requirement 2.a.)\n  - If the aircraft was previously modified under Part II or Part V of earlier Gulfstream SBs, the operator must carry out the modification in accordance with **Part III of Gulfstream SB 112-71C**. (Requirement 2.b.)\n\n- Sets timing for compliance measured from 25 May 1995: initial inspection within **25 hours** time in service from that date; modification to be completed within **300 hours** time in service from that date. (See \"Compliance\".)\n\n- Notes that aircraft modified under earlier Gulfstream SBs or certain drawings are only in **partial compliance** and therefore still require further inspection and modification. (See the middle paragraph under Compliance.)\n\n**Who this affects**\n\n- Aircraft owners and operators of the specified Gulfstream 112-series aeroplanes (by model and serial number).\n- Maintenance organisations and engineers who perform inspections and structural modifications.\n- Regulators (Civil Aviation Safety Authority) as the enforcing authority. The AD also refers to FAA airworthiness directives and Gulfstream service documents, so compliance depends on following those external documents.\n\n**Why it matters (stated purpose and practical effect)**\n\n- The stated reason is repeated reports of cracking in the forward wing spar at the landing gear side brace fitting, and a regulator (FAA) finding that earlier modifications were not a permanent fix. This AD introduces a more extensive modification (via the latest revision of the Gulfstream SB) and prescribes inspections until that modification is completed. (See \"Background\".)\n\n**Costs, incentives and practical trade-offs**\n\n- Who pays: aircraft owners/operators pay for inspections, re-inspections, and the required structural modification (parts, labour, and downtime). (Affected by Requirement 1, Requirement 2, Compliance.)\n\n- Incentives and behaviour: operators face a compliance deadline for modification and inspection intervals; to avoid regulatory breach they must schedule inspections and the more extensive modification within the stated hours. Some operators may postpone until the modification deadline, maintaining higher inspection frequency in the interim.\n\n- Implementation and operational costs: the required modification is structural and will require certified maintenance facilities and trained personnel, creating direct costs and aircraft ground time. Maintenance providers stand to gain the work; smaller operators may face higher relative burden.\n\n- Safety vs. downtime trade-off: the AD balances an interim inspection regime (to catch cracking early) against a required permanent modification. Inspections rely on visual methods (mirror/borescope) which carry a risk of missed cracks depending on technique and skill.\n\n- Regulatory dependence and ambiguity: the AD delegates procedural specifics to Gulfstream SB 112-71C (Parts I–V) and refers to FAA ADs; accurate compliance therefore depends on accessing and following those external documents. That creates dependence on another document for precise instructions and may create costs in obtaining or interpreting the SB.\n\n**Implementation risks and compliance burden**\n\n- Detection risk: borescope/mirror inspections depend on inspector skill and may produce false negatives if not perfectly executed. (Requirement 1.)\n\n- Partial-compliance complexity: aircraft with earlier modifications are explicitly only in partial compliance and must still be reworked per the new SB, which increases administrative and scheduling complexity. (See the Compliance note about earlier SBs and drawings.)\n\n- Enforcement and discretion: the AD sets mandatory times-in-service deadlines and inspection intervals; enforcing those deadlines is the regulator’s role. The AD does not create discretionary exemptions within the text provided.\n\n**Net operational effect (plain terms)**\n\n- Operators must inspect frequently until they complete a mandated structural modification. Completing the modification removes the need for interim inspections as a permanent fix is being required. The financial and downtime costs fall on owners/operators; maintenance providers carry out the work under prescriptive instructions in the referenced Gulfstream SB."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is Amendment 2 to an existing Airworthiness Directive. The scope remains tightly focused on the original safety issue (wing forward spar cracking in specific Gulfstream 112 models). The amendment updates the required modification to a newer service bulletin revision (112-71C) based on FAA findings that earlier fixes were inadequate, but does not expand beyond the original aircraft models or structural issue."},"complexity_factors":["Multiple model and serial number ranges with different applicability rules","Cross-references to five different Gulfstream Service Bulletin versions (112-71, 71A, 71B, 71C Parts I-V)","Conditional logic: Requirement 2 splits into two paths (2.a vs 2.b) depending on prior modification history","Nested compliance exceptions: aircraft with certain prior modifications are noted as only 'partially compliant' and need further work","Reference to overlapping FAA Airworthiness Directives (AD 90-04-07 and 87-14-03) without full context","Technical aviation terminology requiring domain knowledge (borescope, wing spar, side brace fitting, time in service)"],"plain_english_summary":"This CASA Airworthiness Directive mandates mirror/borescope inspections and structural repairs to the upper cap of the forward wing spar near the main landing gear on specified Gulfstream 112 series aeroplanes. It targets aircraft with certain serial numbers unless they've already received the required manufacturer service-bulletin modifications.\n\nIt’s safety-critical: spar cracking can lead to structural failure. The AD requires prompt inspection and completion of the more extensive fixes because earlier partial repairs were deemed inadequate."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-112-13-amdt-2-wing-forward-spar","history":"/api/acts/ad-ac-112-13-amdt-2-wing-forward-spar/history","analysis":"/api/acts/ad-ac-112-13-amdt-2-wing-forward-spar/analysis","conflicts":"/api/acts/ad-ac-112-13-amdt-2-wing-forward-spar/conflicts","importantCases":"/api/acts/ad-ac-112-13-amdt-2-wing-forward-spar/important-cases","documents":"/api/acts/ad-ac-112-13-amdt-2-wing-forward-spar/documents"}}