{"id":"F2006B04601","name":"AD/BELL 214/1 - Main Rotor Tension-Torsion Strap","slug":"ad-bell-214-1-main-rotor-tension-torsion-strap","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44352,"registerId":"commonwealth-F2006B04601-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS 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\nBell Helicopter Textron 214 Series Helicopters","sortOrder":0},{"sectionNumber":"AD/BELL 214/1 Main Rotor Tension-Torsion","sectionType":"part","heading":"AD/BELL 214/1 Main Rotor Tension-Torsion Strap 1/2003","content":"# AD/BELL 214/1 Main Rotor Tension-Torsion Strap 1/2003\n\nDM\n\nApplicability: Model 214B and 214B-1 helicopters, with main rotor tension-torsion (TT) strap, part number 204-012-122-1, \\-5, or 214-010-179-1, installed.\n\nRequirement: Remove and replace any TT strap with 1,200 hours total time in service or 24 or more months since initial installation on any helicopter, whichever occurs first.\n\nThis Directive revises the Limitations section of the maintenance manual by establishing a life limit for TT straps, part number 204-012-122-1, \\-5, or 214-010- 179-1, of 1,200 hours total time in service or 24 months since initial installation on any helicopter, whichever occurs first.\n\nNote: FAA AD 2002-22-14 Amdt 39-12941 refers.\n\nCompliance: Before further flight after 27 November 2002, unless already accomplished.\n\nThis Airworthiness Directive becomes effective on 27 November 2002.\n\nBackground: The original FAA AD requirement (AD 80-17-09) was prompted by an offshore accident of a Model 212 helicopter in which a TT strap reportedly failed in- flight after 2,140 hours total time in service, with resulting loss of the main rotor blade. This Directive restates the requirements AD 80-17-09 and establishes a life limit for TT straps by revising the Limitations section of the maintenance manual. The actions required by this Directive are intended to prevent failure of a TT strap, loss of a main rotor blade, and subsequent loss of control of the helicopter.\n\n![](image.002.jpeg)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 22 November 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 27 November 2002.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — establishing a life limit for a specific helicopter part to prevent a known failure mode. It does not expand beyond the original safety purpose established by the 1980 FAA directive it references."},"complexity_factors":["Single, clearly defined applicability (three specific part numbers on two helicopter models)","Straightforward compliance trigger (hours OR months, whichever first)","No nested exceptions or conditional logic","Minimal cross-referencing (only one FAA AD reference in a note)","Short document (under 300 words) with clear section headers","Only one substantive requirement with immediate effective date"],"plain_english_summary":"This safety order requires Bell 214B/214B‑1 helicopters fitted with the specified tension‑torsion (TT) rotor straps to have those straps removed and replaced after 1,200 flight hours or 24 months from installation, whichever comes first. Flights are prohibited after 27 November 2002 unless the straps meet these limits.\n\nIt affects owners/operators of the listed helicopters and parts, prompted by a 1980 TT strap failure that caused a blade detachment and crash."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD restates prior FAA requirements and formalises a life limit for the TT straps by revising the maintenance manual. That is consistent with the original safety objective (prevent TT strap failure). The instrument does not expand the affected fleet or add unrelated obligations beyond establishing the 1,200‑hour / 24‑month life limit and requiring replacement and maintenance manual revision, so it does not significantly change the original scope of the safety measure."},"complexity_factors":["Short, single‑issue directive (remove/replace specific part at fixed life limits)","Applies to three listed part numbers only","One conditional rule: replace at 1,200 hours TIS OR 24 months since initial installation, whichever occurs first","Cross‑reference to FAA AD 2002-22-14 / earlier FAA AD 80-17-09 and to the maintenance manual 'Limitations' section","Clear, immediate compliance deadline (before further flight after a specified date)","No nested exceptions or multiple compliance pathways"],"plain_english_summary":"**What this instrument does (mechanics)\n\n- Applies to Bell Helicopter models 214B and 214B-1 that have a main rotor tension‑torsion (TT) strap with part number 204-012-122-1, -5, or 214-010-179-1 installed.\n- Requires that any such TT strap that has reached 1,200 hours total time in service (TIS) or has been installed for 24 months or more be removed and replaced. The replacement must be done at whichever limit is reached first (hours or months).\n- Revises the maintenance manual \"Limitations\" section to record this 1,200‑hour / 24‑month life limit for those TT straps.\n- Compliance is mandatory before any further flight after 27 November 2002 (unless the replacement has already been done). The direction is issued under CASA’s regulatory power to correct an unsafe condition.\n\n**Who must act and who pays\n\n- Aircraft operators and owners of affected Bell 214B / 214B-1 helicopters must comply. Their maintenance organisations (AMOs) or technicians must remove and replace the straps and update maintenance records.\n- The operator bears the direct costs: replacement parts, labour, and aircraft downtime.\n\n**Why it matters (stated purpose and background)\n\n- The AD cites a prior FAA action and an earlier accident (a Model 212 TT strap failure reported after 2,140 hours TIS that resulted in loss of a main rotor blade). The stated purpose of the AD is to prevent TT strap failure, loss of a main rotor blade, and consequent loss of helicopter control.\n- Mechanically, the AD enforces a maximum service life (a hard life limit) for the listed TT strap parts to reduce the risk of in‑flight failure.\n\n**Practical effects, trade‑offs and implementation considerations\n\n- Immediate operational effect: operators must track each strap’s installed time and age, schedule replacements at the prescribed limit, and update the maintenance manual limits.\n- Costs and burdens: replacement parts and skilled labour, lost flying hours while the aircraft is grounded for the work, and administrative effort to verify installation dates and cumulative hours. These costs are borne by operators and are ongoing for any affected aircraft reaching the limit.\n- Safety trade‑off: the AD shifts behaviour from relying on inspection/monitoring alone to enforcing a preventive replacement policy. That reduces the tail risk of sudden strap failure but increases predictable maintenance expenditure and downtime.\n- Compliance risk and implementation issues: availability of replacement parts, reliability of historical records for time‑since‑installation (especially for older or second‑hand straps), and potential short‑term grounding if parts are not immediately available.\n- Market effects: the measure raises operating costs for affected operators. Because it is targeted (specific models and part numbers), the burden is concentrated on those operators; benefits (reduced crash risk) accrue to crew, passengers and public safety more broadly.\n- Administrative discretion: minimal. The AD prescribes required action and a fixed compliance date; it does not leave substantive discretion to operators beyond how they schedule and perform the replacement.\n\n**Net mechanism (who decides, who changes behaviour)\n\n- Who decides: CASA (via its delegate) prescribes the action; maintenance organisations carry it out.\n- Who pays: the operator/owner pays for parts, labour and downtime.\n- What behaviour changes: operators must replace straps at a defined life limit and keep records; maintenance manuals must be updated to show the new life limit.\n\n**Analytical note on the source claim**\n- The AD’s stated preventive purpose (avoid strap failure leading to rotor loss) is consistent with imposing a conservative life limit. The cost is predictable and recurring (part replacement and downtime). The main implementation risks are part supply and accurate records of strap time/age; where records are missing, operators may need to assume the strap is at or near the limit and replace it immediately, increasing short‑term costs. The rule is prescriptive rather than discretionary, so enforcement and compliance monitoring are the primary administrative tasks.\n\n(References in the AD include earlier FAA ADs; this Australian AD restates those safety requirements and formally inserts the life limit into the helicopter maintenance manual.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-214-1-main-rotor-tension-torsion-strap","history":"/api/acts/ad-bell-214-1-main-rotor-tension-torsion-strap/history","analysis":"/api/acts/ad-bell-214-1-main-rotor-tension-torsion-strap/analysis","conflicts":"/api/acts/ad-bell-214-1-main-rotor-tension-torsion-strap/conflicts","importantCases":"/api/acts/ad-bell-214-1-main-rotor-tension-torsion-strap/important-cases","documents":"/api/acts/ad-bell-214-1-main-rotor-tension-torsion-strap/documents"}}