{"id":"F2006B06470","name":"AD/R44/20 - Main Rotor Swashplate and Tail Rotor Bolts","slug":"ad-r44-20-main-rotor-swashplate-and-tail-rotor-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47965,"registerId":"commonwealth-F2006B06470-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\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 CASR 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\n![](image.001.png)  \n\nRobinson R44 Series Helicopters","sortOrder":0},{"sectionNumber":"AD/R44/20 Main Rotor Swashplate and Tail","sectionType":"part","heading":"AD/R44/20 Main Rotor Swashplate and Tail Rotor Bolts 1/2004","content":"# AD/R44/20 Main Rotor Swashplate and Tail Rotor Bolts 1/2004\n\nTX\n\nApplicability: Model R44 helicopters.\n\nRequirement: 1. For all R44 and R44 II helicopters except those serial numbers specified in Requirement 2 of this Directive:\n\n    Determine if maintenance has been performed after 7 February 2003 on the areas specified in Figure 1 of this Directive, and determine if any bolt, part number NAS6605-31, shown on Figure 1 has been replaced for any reason.\n\n    b. If any bolt has been replaced, or if it is uncertain whether any bolt has been replaced after 7 February 2003, remove the paint from the bolt head to reveal the vendor identification marking. Determine if the bolt vendor identification is 01DO.\n\n    (i) If the vendor identification is 01DO, comply with Requirements 3 and 4.\n\n    2. The following R44 and R44 II helicopters must comply with Requirements 3 and 4 of this Directive:\n\n    Model R44 helicopters, serial numbers 0210, 0565, 0641, 0987 and 1312 through 1349, except 1345 and 1346; and\n\n    b. Model R44 II helicopters, serial numbers 10010, 10062, and 10083 through 10212, except 10092, 10173, 10204, 10207, 10210, and 10211.\n\n    3. For the helicopters affected by Requirements 1.b.(i) and 2. of this Directive, accomplish the following:\n\n    Visually inspect each bolt for fretting residue under the bolt head, which indicates a loose, potentially cracked bolt.\n\n    b. Apply 10-15 ft-lb (13-20 Nm) torque to each bolt head and verify no rotation. See Figure 1 of this Directive.\n\n    c. If residue or rotation of the bolt is found, replace each affected bolt with a serviceable bolt that does not have a vendor identification marking of 01DO.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This appears to be a standard targeted airworthiness directive addressing a specific unsafe condition (defective vendor bolts). The scope remains tightly focused on the identified safety issue with Robinson R44 helicopters and does not appear to have expanded beyond its original safety purpose."},"complexity_factors":["Multiple conditional pathways: Requirement 1 creates a two-step determination (maintenance history → bolt replacement history → vendor marking check), while Requirement 2 creates an alternative mandatory pathway via serial number lists","Nested sub-requirements: Requirements 3 and 4 are cross-referenced from multiple upstream conditions (1.b.(i) and 2), creating dependency chains","Specific technical thresholds: Precise torque specifications (10-15 ft-lb / 13-20 Nm) and date cutoffs (7 February 2003)","Exception-within-exception serial number lists: Requirement 2 contains inclusive ranges with specific exclusions (e.g., \"1312 through 1349, except 1345 and 1346\")","Visual reference dependency: Multiple requirements refer to \"Figure 1\" which is not reproduced in the text, making the directive incomplete without the accompanying diagram"],"plain_english_summary":"This AD requires owners/operators of Robinson R44 and R44 II helicopters to inspect certain main- and tail-rotor bolts for suspect NAS6605-31 parts from vendor marked \"01DO\" and, for specified serial-numbered aircraft, perform mandatory inspections regardless of history. It mandates checking for fretting and proper torque and replacing any defective or marked bolts. The action prevents potential catastrophic rotor failure."},"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This directive is narrowly targeted at correcting a specific unsafe condition (possible loose or cracked NAS6605-31 bolts marked 01DO) on specified R44 and R44 II helicopters. It does not broaden the subject beyond that original safety aim: it prescribes inspections, a torque-check, and replacement where evidence of fretting or rotation exists, limited to defined models/serial numbers or cases where maintenance after a set date could have introduced the suspect bolts (Requirements 1–3). There is no indication in the text that the directive extends into additional systems, broader maintenance rules, or unrelated aircraft types, so the scope remains consistent with the stated safety purpose."},"complexity_factors":["Applicability limited to two helicopter models (R44 and R44 II) with explicit serial-number sublists in Requirement 2","Conditional logic depending on maintenance after a specific date (7 February 2003) in Requirement 1","Vendor identification check (paint removal and visual ID) and specific vendor code trigger (01DO) in Requirement 1.b","Three-step inspection/re-test/replace procedure with a measured torque specification (10–15 ft‑lb / 13–20 Nm) in Requirement 3","Requirement to replace with a bolt that does not carry a particular vendor ID (01DO) in Requirement 3.c","Reference to an external figure (Figure 1) for locating the affected areas/bolts","Cross-reference to CASR 1998 subregulation 39.1(1) as the legal basis for issuing the AD"],"plain_english_summary":"**What this directive does (mechanically):**\n\n- Applies to Robinson Model R44 and R44 II helicopters (see Requirement 1 and 2).\n- Requires operators or maintenance personnel to check whether maintenance affecting the areas shown in Figure 1 was carried out after 7 February 2003 and whether any bolt with part number NAS6605-31 was replaced (Requirement 1).\n- If a bolt may have been replaced after that date, the paint must be removed from the bolt head to read the vendor identification marking. If the marking is \"01DO\", the helicopter must undergo the inspections and actions in Requirements 3 and 4 (Requirement 1.b.i).\n- A specified list of serial-numbered R44 and R44 II helicopters must comply with the inspections and actions regardless of the maintenance-history check (Requirement 2).\n- For affected helicopters (Requirements 1.b.i and 2):\n  - Visually inspect each specified bolt for fretting residue under the bolt head (this can indicate a loose or cracked bolt) (Requirement 3.a).\n  - Apply 10–15 ft‑lb (13–20 Nm) torque to each bolt head and verify the bolt does not rotate (Requirement 3.b).\n  - If fretting residue or rotation is found, replace the affected bolt with a serviceable bolt that does not carry vendor identification \"01DO\" (Requirement 3.c).\n\n**Why the regulator says this is required:**\n\n- The directive is issued under subregulation 39.1(1) of CASR 1998 to correct an identified unsafe condition related to main rotor swashplate and tail rotor bolts. The stated purpose is to ensure bolts that may be loose or cracked are identified and replaced so the unsafe condition is corrected.\n\n**Who it affects and who pays:**\n\n- Affected parties: owners and operators of Robinson R44 and R44 II helicopters in the serial-number ranges listed, and maintenance organisations that service those helicopters.\n- Who pays: aircraft owners/operators bear the inspection, paint removal (to read vendor ID), torque-checking, any replacement parts, and associated labour and downtime costs. Maintenance organisations perform the work under the operator's direction.\n\n**What decisions and behaviour change:**\n\n- CASA (through its delegate) has directed the mandatory inspections and replacements (the decision to issue the AD is from the CASA delegate; see opening paragraph referencing subregulation 39.1(1)).\n- Operators/maintainers must: check maintenance records and bolt vendor markings, remove paint to read markings where necessary, perform visual inspections for fretting, torque-check bolts to 10–15 ft‑lb, and replace any bolt that shows fretting or rotates when torqued — using only replacements without vendor ID \"01DO\".\n\n**Implementation, costs and trade-offs:**\n\n- Direct costs: labour for inspections, time to remove paint on bolt heads where required, possible grounding/downtime while inspections and replacements are carried out, and cost/availability of compliant replacement bolts.\n- Administrative/compliance costs: recording the inspections and replacements, verifying vendor markings, and ensuring replacements do not have vendor ID \"01DO\".\n- Supply-side effects: increased demand for non-01DO NAS6605-31 bolts (or approved equivalent) may create sourcing pressure for parts suppliers and maintenance organisations.\n- Risk and practical issues: paint removal can be delicate (risk of marking surfaces), vendor identification visibility might be poor, misidentification could lead to unnecessary replacements or missed unsafe parts, and operators in remote locations may face delays sourcing compliant bolts.\n\n**Concentrated benefits and diffuse costs:**\n\n- Benefit is concentrated on airworthiness/safety of affected helicopters and on any individual operator that avoids a bolt failure. Costs (inspection and replacement) are borne by helicopter owners/operators and maintenance providers.\n\n**Compliance enforcement and verification points:**\n\n- Compliance requires physical verification (visual inspection and torque test) and documentary checks (maintenance history and records of replacement). The directive references Figure 1 for the areas and bolt locations that must be checked, so accurate use of that Figure is necessary for correct compliance.\n\n**Reference to specific requirements in the AD:**\n\n- Maintenance-history and vendor-mark checks: Requirement 1 (including 1.b and 1.b.(i)).\n- Serial-numbered helicopters forced to comply: Requirement 2.\n- Inspections, torque test and replacement requirement: Requirement 3 (3.a—3.c).\n\n(End of summary.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-r44-20-main-rotor-swashplate-and-tail-rotor-bolts","history":"/api/acts/ad-r44-20-main-rotor-swashplate-and-tail-rotor-bolts/history","analysis":"/api/acts/ad-r44-20-main-rotor-swashplate-and-tail-rotor-bolts/analysis","conflicts":"/api/acts/ad-r44-20-main-rotor-swashplate-and-tail-rotor-bolts/conflicts","importantCases":"/api/acts/ad-r44-20-main-rotor-swashplate-and-tail-rotor-bolts/important-cases","documents":"/api/acts/ad-r44-20-main-rotor-swashplate-and-tail-rotor-bolts/documents"}}