{"id":"F2006B10913","name":"AD/JETSTREAM/44 - MLG Wheel Nut","slug":"ad-jetstream-44-mlg-wheel-nut","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56453,"registerId":"commonwealth-F2006B10913-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JETSTREAM/44 - MLG Wheel Nut","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)  \nBritish Aerospace BAe 3100 (Jetstream) Series Aeroplanes\n\nAD/JETSTREAM/44 MLG Wheel Nut 8/91\n\nApplicability: Model HP137 MK1 aircraft, Jetstream Series 200, Series 3100, and Series 3200 aircraft with installed main landing gear types listed in BAe SB 32-A-JA-910140.\n\nRequirement: Action in accordance with Mandatory BAe Alert SB 32-A-JA 910140.\n\nNote: BAe (Dynamics) Ltd SB 32-46 refers.\n\nCompliance: As specified in the Requirement Document.\n\nNote: The Requirement Document compliance statement is applicable in its entirety to Australian registered aircraft.\n\nBackground: Instances of main wheel roller bearing break-up have been reported. This has caused the loss of a main landing gear wheel. Inspection revealed that the main wheel bearing outer race had passed over the axle nut and the wheel departed from the aircraft.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard single-issue airworthiness directive addressing a specific mechanical defect. It has not expanded beyond its original purpose of mandating inspection/repair of main landing gear wheel nuts on affected Jetstream aircraft."},"complexity_factors":["Very short document (under 200 words)","Only 1 substantive requirement (comply with manufacturer bulletin)","No defined terms section","No cross-references to other legislation beyond the enabling regulations (CAR 1998 Part 39)","Single applicability test (aircraft model + landing gear type)","No conditional logic or nested exceptions","Incorporates external technical document by reference (BAe SB 32-A-JA-910140)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific British Aerospace Jetstream aircraft.\n\n**What it does:**\nOrders owners and operators of certain Jetstream aircraft models to follow a specific safety bulletin from the manufacturer (British Aerospace). The bulletin addresses a dangerous problem where main landing gear wheel nuts can fail, causing wheels to fall off during flight.\n\n**Who it affects:**\n- Owners and operators of:\n  - HP137 MK1 aircraft\n  - Jetstream Series 200, 3100, and 3200 aircraft\n- Only applies if the aircraft has the specific main landing gear types listed in the manufacturer's safety bulletin\n\n**Why it matters:**\nThe directive responds to reports where main wheel bearings broke apart, allowing the wheel bearing outer race to slip past the axle nut. This caused wheels to detach from aircraft mid-flight — a serious safety hazard. The directive makes inspection and repair mandatory to prevent catastrophic failure.\n\n**What must be done:**\nAircraft operators must follow the exact instructions in British Aerospace Alert Service Bulletin 32-A-JA-910140. The compliance deadline and specific actions are set by that manufacturer document, which is incorporated into this Australian law."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive’s scope aligns with the stated purpose in the text: it targets specific Jetstream models and requires adherence to the manufacturer’s mandatory bulletin to prevent main wheel loss. The AD does not expand or narrow that scope beyond the aircraft types and the actions specified in BAe Alert SB 32-A-JA 910140 as presented in the source text (Applicability; Requirement; Background)."},"complexity_factors":["Narrow technical scope limited to specific Jetstream models and listed main landing gear types (Applicability)","Substantial delegation of technical content to an external mandatory manufacturer document (BAe Alert SB 32-A-JA 910140) rather than spelling out steps in the AD itself (Requirement)","Cross-reference to an additional manufacturer service bulletin (BAe (Dynamics) Ltd SB 32-46) which may add requirements or clarification (Note)","Compliance is mandatory for Australian-registered aircraft but the AD does not state the specific inspection/repair tasks, timing, or parts — those are in the Requirement Document (Compliance; Requirement)","Operational impacts (downtime, parts supply, labour) depend entirely on the external bulletin’s specifications, creating uncertainty from the AD text alone (Requirement; Compliance)"],"plain_english_summary":"This AD mandates that operators of certain British Aerospace Jetstream aeroplanes on the Australian register carry out the actions in Mandatory BAe Alert SB 32-A-JA 910140 to address main wheel roller bearing failures that have led to wheel loss. It makes the manufacturer’s inspection/repair/modification requirements compulsory, placing compliance costs and operational downtime on affected operators and their maintenance providers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jetstream-44-mlg-wheel-nut","history":"/api/acts/ad-jetstream-44-mlg-wheel-nut/history","analysis":"/api/acts/ad-jetstream-44-mlg-wheel-nut/analysis","conflicts":"/api/acts/ad-jetstream-44-mlg-wheel-nut/conflicts","importantCases":"/api/acts/ad-jetstream-44-mlg-wheel-nut/important-cases","documents":"/api/acts/ad-jetstream-44-mlg-wheel-nut/documents"}}