{"id":"F2006B09702","name":"AD/F27/135 - Nose Wheel Steering","slug":"ad-f27-135-nose-wheel-steering","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115866,"registerId":"commonwealth-F2006B09702-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F27/135 - Nose Wheel Steering","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)  \nFokker F27 Series Aeroplanes\n\nAD/F27/135 Nose Wheel Steering 13/93\n\nApplicability: All F27 aircraft (except MK 050) series fitted with Walter Kidde Nose-wheel Steering System (steering unit gearbox housing assembly) P/N 893954.\n\nRequirement: Unless previously carried out, action in accordance with Fokker SB F27/32-166 dated 7 September 1993.\n\nNote: BLA AD 93-132 (A) and Fokker F27 Maintenance Circular No 32-6 refers.\n\nCompliance: Within 500 hours time in service from 1 December 1993 or by 1 February 1994, whichever occurs first.\n\nThereafter, recheck the bolt torque value at each B-check.\n\nBackground: The manufacturer has been advised of broken dowels pins in the Walter Kidde nose- wheel steering system. This has resulted in loss of directional control after touch down and in some cases the subsequent collapse of the nose gear.","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 mechanical defect in a specific aircraft system. It has not expanded beyond its original purpose of mandating a critical safety fix for the Walter Kidde nose-wheel steering system."},"complexity_factors":["Single, specific technical requirement (follow one service bulletin)","Limited applicability (one aircraft type, one specific part number)","Clear compliance deadline (500 hours or fixed date, whichever first)","Simple ongoing requirement (torque check at B-checks)","No nested exceptions, conditional logic, or extensive cross-referencing","Background explanation included in plain language"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of specific Fokker F27 aircraft to inspect and fix a dangerous defect in the nose wheel steering system.\n\n**Who it affects:**\n- All Fokker F27 aircraft (except the MK 050 model)\n- Only those fitted with a specific Walter Kidde nose-wheel steering system (part number 893954)\n\n**The problem:**\nThe steering system has a design flaw where **dowel pins can break**. This has already caused:\n- Loss of steering control after landing\n- In some cases, complete collapse of the nose landing gear\n\n**What must be done:**\n- Follow the manufacturer's service bulletin (Fokker SB F27/32-166) to fix the issue\n- Complete the work within 500 flight hours or by 1 February 1994 — whichever comes first\n- After that, check the bolt torque (tightness) at every B-check (a routine maintenance inspection)\n\n**Why it matters:**\nThis is a **life-critical safety fix**. Broken steering on landing can cause runway excursions, gear collapse, and potential injuries or fatalities. The directive makes compliance mandatory — not optional."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"There is no indication in the instrument itself that the scope has changed from its stated purpose. The AD explicitly targets F27 aircraft fitted with Walter Kidde nose-wheel steering P/N 893954 (except MK 050) and requires the maintenance action in Fokker SB F27/32-166 within the stated time window and ongoing B-check torque rechecks to address broken dowel pins that can cause loss of directional control and nose gear collapse. The Applicability, Requirement, Compliance and Background sections together define and limit the scope."},"complexity_factors":["Technical specificity: identifies a single part number (P/N 893954) and a specific steering system (Walter Kidde) that must be located and inspected. (Applicability)","Applicability exception: excludes a specific variant (MK 050) which requires implementers to confirm aircraft variant. (Applicability)","Delegated technical detail: the AD requires action by reference to an external manufacturer Service Bulletin (Fokker SB F27/32-166), so implementers must obtain and follow that document. (Requirement)","Fixed compliance window plus ongoing checks: gives a short initial compliance period (within 500 hours or by a specific date) and an indefinite recurring requirement (recheck torque at each B-check), introducing scheduling and record-keeping obligations. (Compliance)","Cross-references to other documents (BLA AD 93-132 (A) and Fokker Maintenance Circular No 32-6) that implementers may need to consult. (Note)"],"plain_english_summary":"Mandates owners/operators of Fokker F27s fitted with Walter Kidde nose‑wheel steering gearbox P/N 893954 (except MK 050) to carry out the work specified in Fokker SB F27/32‑166 within 500 flight hours of 1 Dec 1993 or by 1 Feb 1994, then recheck bolt torque at every B‑check. It addresses broken dowel pins that can cause loss of directional control or nose‑gear collapse; operators pay the inspection/repair costs and face the associated downtime."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f27-135-nose-wheel-steering","history":"/api/acts/ad-f27-135-nose-wheel-steering/history","analysis":"/api/acts/ad-f27-135-nose-wheel-steering/analysis","conflicts":"/api/acts/ad-f27-135-nose-wheel-steering/conflicts","importantCases":"/api/acts/ad-f27-135-nose-wheel-steering/important-cases","documents":"/api/acts/ad-f27-135-nose-wheel-steering/documents"}}