{"id":"F2006B03544","name":"AD/BAe 146/97 - Nose Landing Gear - Differential Box Collar Cap Screw Torque Reinstatement","slug":"ad-bae-146-97-nose-landing-gear-differential-box-collar-cap-screw-torque-reinstatement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43111,"registerId":"commonwealth-F2006B03544-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/97 - Nose Landing Gear - Differential Box Collar Cap Screw Torque Reinstatement","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)  \n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nBritish Aerospace BAe 146 Series Aeroplanes\n\nAD/BAe 146/97 Nose Landing Gear \\- Differential Box Collar Cap\n\nScrew Torque Reinstatement\n\n  \n4/2002\n\nDM\n\nApplicability: All BAe 146-100, -200 and \\-300 series aeroplanes, and all Avro 146-RJ70, -RJ85 and\n\n\\-RJ100 series aeroplanes.\n\nRequirement: 1. Inspect the nose landing gear differential box in accordance with BAe Systems (Operations) Service Bulletin ISB.32-168 to establish that they are torque loaded in accordance with Messier Dowty Service Bulletin 146-32-154, which calls for inspection/reinstatement of the correct torque settings.\n\n2. Do not fit to an aeroplane a nose landing gear differential box that does not comply with Requirement 1 of this Airworthiness Directive.\n\nNote: UK CAA Airworthiness Directive 004-08-2001 refers.\n\nCompliance: For Requirement 1: By 30 March 2002.\n\nFor Requirement 2: After the effective date of this Airworthiness Directive. This Airworthiness Directive becomes effective on 27 February 2002.\n\nBackground: The CAA(UK) advises that there have been several reports of uncommanded inputs to the nose wheel steering. Investigation determined the cause to be significantly low torque settings of the nose landing gear differential box collar cap screw. This Directive is therefore issued to reinstate the original design standard torque of 60 lb/in.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 20 February 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 27 February 2002.\n\n  \nPage 1 of 1","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD restores the original design torque standard and mandates a one‑time inspection/reinstatement plus a prohibition on fitting unchecked parts. It does not expand the listed aircraft types or introduce recurring monitoring requirements beyond the inspection/reinstatement and ban on non‑compliant fittings (see Applicability; Requirement 1; Requirement 2; Compliance)."},"complexity_factors":["Technical specificity: sets a single numeric torque target (60 lb/in) that must be reinstated (Background).","Dependency on external documents: inspection and torque reinstatement procedures are specified by BAe Systems (Operations) Service Bulletin ISB.32-168 and Messier Dowty Service Bulletin 146-32-154 (Requirement 1).","Fleet breadth: applies to all BAe 146-100/-200/-300 and all Avro 146-RJ70/-RJ85/-RJ100 variants (Applicability).","Prohibitory operational rule: bars fitting a differential box that does not comply with Requirement 1 after the AD's effective date (Requirement 2; Compliance).","Fixed, near-term compliance timing: a one-time inspection deadline (by 30 March 2002) and an effective date (27 February 2002) create scheduling pressure (Compliance).","Enforcement and source of authority: issued by a CASA delegate under subregulation 39.1(1) of CAR 1998, so action is mandatory and administered by the regulator (opening paragraph and signature).","Root cause linkage: issued in response to reports of uncommanded nose wheel steering traced to low torque settings, tying the measure to a specific safety fault (Background)."],"plain_english_summary":"This Airworthiness Directive requires operators of all **BAe 146** and **Avro 146‑RJ** series aeroplanes to inspect the nose landing gear differential box and, where necessary, reinstate the collar cap screw torque to the original design value of 60 lb/in using the specified Service Bulletins. It also prohibits fitting a differential box that has not been checked. CASA's delegate issued the AD under CAR subreg 39.1(1); operators pay for inspections/repairs and must change maintenance practice by the stated dates."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific mechanical defect (loose torque settings on a single component) in a defined aircraft family. There is no evidence of scope creep; the directive remains tightly focused on the nose landing gear differential box collar cap screw issue as originally identified."},"complexity_factors":["Single-page document with only 2 operative requirements","Minimal defined terms (only standard aviation acronyms like 'CASA', 'CAA(UK)')","No nested exceptions or conditional logic — requirements are absolute","Straightforward compliance timeline with single deadline","Cross-reference to only 2 external technical documents (Service Bulletins) and 1 related UK directive","Clear applicability section listing specific aircraft models by series"],"plain_english_summary":"This CASA safety order requires owners and operators of BAe 146 and Avro RJ aircraft to inspect the nose landing gear differential box collar cap screw to verify correct torque and bans fitting any nose gear part that hasn’t passed inspection. It responds to incidents of uncommanded nose-wheel steering traced to under‑torqued bolts, posing a serious ground‑handling risk. The inspection deadline was 30 Mar 2002; the fit‑ban began 27 Feb 2002."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-97-nose-landing-gear-differential-box-collar-cap-screw-torque-reinstatement","history":"/api/acts/ad-bae-146-97-nose-landing-gear-differential-box-collar-cap-screw-torque-reinstatement/history","analysis":"/api/acts/ad-bae-146-97-nose-landing-gear-differential-box-collar-cap-screw-torque-reinstatement/analysis","conflicts":"/api/acts/ad-bae-146-97-nose-landing-gear-differential-box-collar-cap-screw-torque-reinstatement/conflicts","importantCases":"/api/acts/ad-bae-146-97-nose-landing-gear-differential-box-collar-cap-screw-torque-reinstatement/important-cases","documents":"/api/acts/ad-bae-146-97-nose-landing-gear-differential-box-collar-cap-screw-torque-reinstatement/documents"}}