{"id":"F2006B10952","name":"AD/JETSTREAM/81 - Nose Wheel Steering Jack Seal Change","slug":"ad-jetstream-81-nose-wheel-steering-jack-seal-change","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56519,"registerId":"commonwealth-F2006B10952-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JETSTREAM/81 - Nose Wheel Steering Jack Seal Change","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/81 Nose Wheel Steering Jack Seal Change 1/99\n\nApplicability: All British Aerospace Regional Aircraft HP137 Mk 1 Jetstream Series 200, 3100 and 3200 series aircraft.\n\nRequirement: Modify the nose wheel steering jack in accordance with British Aerospace Regional Aircraft Service Bulletin 32-JA900942 Revision 5 and the Landing Gear manufacturer’s Service Bulletin, APPH Limited SB32-51 Revision 5.\n\nNote: UK CAA AD 003-09-98 dated 22 Oct 98 refers.\n\nCompliance: At the next scheduled overhaul of the nose wheel steering jack but no later than 30 September 1999.\n\nThis Airworthiness Directive becomes effective on 28 January 1999.\n\nBackground: Following a recent serious incident it was discovered that the nose wheel steering jack seals were deteriorating and contaminating the jack to the extent of causing steering lock up. This Directive mandates the incorporation of a modified, improved seal to prevent steering jack lock up.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect. It has not expanded beyond its original purpose of mandating a seal replacement to prevent nose wheel steering failure."},"complexity_factors":["Single, specific technical requirement (seal replacement)","Only 2 defined applicability criteria (aircraft model series)","Single compliance deadline with one alternative timing option","No nested exceptions or conditional logic","Cross-references only to external manufacturer bulletins, not to other legislative provisions","Extremely short document (under 200 words)"],"plain_english_summary":"This CASA Airworthiness Directive mandates that operators of certain British Aerospace Jetstream Series 200, 3100 and 3200 aircraft replace deteriorating nose‑wheel steering jack seals with improved parts per the manufacturer service bulletins by the next jack overhaul or by 30 September 1999. It targets all owners/operators of the affected models to prevent seal‑caused contamination and nose‑wheel steering lockups after a related serious incident, reducing the risk of runway or control accidents."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's scope is limited to mandating a seal modification for the listed Jetstream models to address the identified steering jack contamination and lock‑up. It does not expand to other components, types, or operational restrictions beyond the specified modification and compliance deadline."},"complexity_factors":["Applicability covers multiple model series (Series 200, 3100, 3200) so all operators of those types must assess fleets (Applicability).","Mandated technical change requires following two external service bulletins (British Aerospace SB 32-JA900942 Rev 5 and APPH SB32-51 Rev 5) (Requirement).","Compliance timing ties the modification to each jack's next scheduled overhaul but also imposes a hard deadline (next overhaul or 30 September 1999) (Compliance).","Safety‑critical failure mode (steering lock‑up) motivates mandatory action and limits discretion on deferral (Background).","Coordination with landing‑gear manufacturer (APPH Limited) and maintenance organisations is necessary to implement the modification (Requirement).","Cross‑reference to UK CAA AD may require operators to track foreign regulator materials for context (Note)."],"plain_english_summary":"This Airworthiness Directive requires operators of British Aerospace Jetstream Series 200, 3100 and 3200 aircraft to modify the nose‑wheel steering jack by fitting an improved seal in accordance with specified service bulletins. The work must be done at the next scheduled overhaul but no later than 30 September 1999. The directive responds to reported seal deterioration that contaminated jacks and caused steering lock‑up, and mandates a seal change to prevent that failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jetstream-81-nose-wheel-steering-jack-seal-change","history":"/api/acts/ad-jetstream-81-nose-wheel-steering-jack-seal-change/history","analysis":"/api/acts/ad-jetstream-81-nose-wheel-steering-jack-seal-change/analysis","conflicts":"/api/acts/ad-jetstream-81-nose-wheel-steering-jack-seal-change/conflicts","importantCases":"/api/acts/ad-jetstream-81-nose-wheel-steering-jack-seal-change/important-cases","documents":"/api/acts/ad-jetstream-81-nose-wheel-steering-jack-seal-change/documents"}}