{"id":"F2006B10320","name":"AD/GROB 115/13 - Rear Fuselage Bulkhead","slug":"ad-grob-115-13-rear-fuselage-bulkhead","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56073,"registerId":"commonwealth-F2006B10320-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GROB 115/13 - Rear Fuselage Bulkhead","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)  \nGrob G115 Series Aeroplanes\n\nAD/GROB 115/13 Rear Fuselage Bulkhead 1/99 DM\n\nApplicability: All Grob models G115C2 and G115D.\n\nRequirement: 1. Remove the Antispin strake and fuselage closure fairing from under the horizontal stabiliser to gain access to the rear fuselage bulkhead. See Figure 1.\n\n![](image.002.png)2. Inspect along the upper edge of the bulkhead, looking for cracking, disbonding and crazing in the shaded areas shown in Figure 2. Using a light and a mirror through the access hole in the bulkhead, similarly inspect the upper edge on the front of the bulkhead.\n\n![](image.003.png)  \n\nFigure 1\n\nFigure 2\n\nCompliance: Unless inspected within the last 50 hours time in service, inspect within 50 hours time in service after the effective date of this AD. Re-inspect every 100 hours time in service, until the whole upper edge of the bulkhead, including its attachment to the fuselage skin, is modified or repaired in accordance with a design approved by Grob or a CAR 35 delegate or authorised person.\n\nThis Airworthiness Directive becomes effective on 25 November 1998.\n\nBackground: Aircraft have been found with cracks in the bulkhead and disbonding of the flange of the bulkhead from the fuselage skin. Such defects weaken the attachment of the whole tail assembly.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific structural defect in specific aircraft models. It has not expanded beyond its original purpose of ensuring airworthiness of the rear fuselage bulkhead."},"complexity_factors":["Single, specific mechanical task (visual inspection of one component)","Only 2 defined applicability criteria (specific aircraft models)","Simple compliance timeline (50 hours initial, 100 hours recurring)","No cross-references to other legislation beyond generic CAR 35 mention","Clear termination condition (when modification completed)","Straightforward background explanation linking defect to safety risk"],"plain_english_summary":"This safety order requires owners/operators of Grob G115C2 and G115D aircraft to inspect the rear fuselage bulkhead for cracks, bond separation, and surface damage, with the first check within 50 flight hours and repeat inspections every 100 hours until a permanent fix is installed. It affects aircraft operators and maintenance engineers because bulkhead failure can compromise the tail attachment and risk catastrophic loss of control."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's scope is self-contained: it applies only to G115C2 and G115D models and mandates inspection/re-inspection until an approved modification or repair is installed. The text shows no expansion or narrowing of applicability beyond that stated, nor later amendments; therefore no scope change is evident from the provided instrument."},"complexity_factors":["Narrow applicability limited to Grob G115C2 and G115D (Applicability).","Physical access step: removal of antispin strake and fuselage closure fairing to reach the bulkhead (Requirement 1).","Inspection technique requires visual inspection along the upper edge and use of a light and mirror through an access hole (Requirement 2).","Defect types to detect: cracking, disbonding and crazing in specified shaded areas (Requirement 2; Figures referenced).","Compliance timing: initial inspection within 50 hours time in service if not recently inspected, then re-inspect every 100 hours (Compliance).","Termination condition: inspections continue until the upper edge is modified or repaired in accordance with a design approved by Grob or a CAR 35 delegate/authorised person (Compliance) — creates reliance on OEM or regulator-authorised design approval.","Safety-critical location: defects cited as weakening the tail assembly, increasing the stakes of inspection accuracy and prompt repair (Background).","Operational impacts implied: recurring inspections cause repeated downtime and potential repair costs; repair/design approval process may introduce administrative or scheduling delay."],"plain_english_summary":"This Airworthiness Directive requires operators of Grob G115C2 and G115D aircraft to remove under-tail fairings, inspect the rear fuselage bulkhead upper edge for cracking, disbonding or crazing within 50 hours (unless already done), and repeat inspections every 100 hours until an approved repair/modification is fitted. It responds to discovered bulkhead cracks and disbonds that can weaken the tail attachment; compliance creates inspection labour and downtime, possible repair costs, and dependence on Grob or a CAR 35 delegate to approve any design fix."}},"importantCases":[],"_links":{"self":"/api/acts/ad-grob-115-13-rear-fuselage-bulkhead","history":"/api/acts/ad-grob-115-13-rear-fuselage-bulkhead/history","analysis":"/api/acts/ad-grob-115-13-rear-fuselage-bulkhead/analysis","conflicts":"/api/acts/ad-grob-115-13-rear-fuselage-bulkhead/conflicts","importantCases":"/api/acts/ad-grob-115-13-rear-fuselage-bulkhead/important-cases","documents":"/api/acts/ad-grob-115-13-rear-fuselage-bulkhead/documents"}}