{"id":"F2006B05719","name":"AD/PA-31/130 - Rudder Torque Tube Assembly and Rudder Rib","slug":"ad-pa-31-130-rudder-torque-tube-assembly-and-rudder-rib","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135518,"registerId":"commonwealth-F2006B05719-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/130 - Rudder Torque Tube Assembly and Rudder Rib","content":"![](image.001.png)\n\nAIRWORTHINESS 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\nPiper PA-31 Series Aeroplanes\n\nAD/PA-31/130 Rudder Torque Tube Assembly and\n\nRudder Rib\n\n  \n2/2004\n\nApplicability: Model\n\nPA-31, PA-31-300, PA-31-325 PA-31-350\n\nPA-31P\n\nPA-31P-350 PA-31T\n\nPA-31T1 PA-31T2 PA-31T3\n\n  \n\nSerial numbers\n\n31-2 through 31-8312019\n\n31-5001 through 31-8553002\n\n31P-1 through 31P-7730012\n\n31P-8414001 through 31P-8414050\n\n31T-7400001 through 31T-8120104\n\n31T-7804001 through 31T-1104017\n\n31T-8166001 through 31T-1166008\n\n31T-8275001 through 31T-5575001\n\nRequirement: 1. Install an inspection hole in the rudder skin for the rudder torque tube assembly in accordance with Piper Aircraft Service Bulletin (SB) No. 1105A, dated 22 September 2003; or, instead of installing an inspection hole, use the tooling hole in the rudder bottom rib. Enlargement of the diameter of the tooling hole by a maximum of 0.25 inches may be accomplished to facilitate inspection and corrosion treatment.\n\n    2. Visually inspect the rudder torque tube and associated ribs for corrosion in accordance with SB No. 1105A.\n\n    3. If corrosion damage is detected:\n\n    Replace the rib/rudder torque tube assembly; or,\n\n    b. Repair the damaged torque tube using an approved repair design. FAA AD 2003-24-07 paragraph (f) specifies repair issues to be addressed.\n\nNote: FAA AD 2003-24-07 Amdt 39-13376 refers.\n\nPiper PA-31 Series Aeroplanes\n\nAD/PA-31/130 (continued)\n\nCompliance: 1. Within 150 hours time in service after 19 February 2004, unless already accomplished.\n\n    2. Before further flight after accomplishment of Requirement 1, and thereafter at intervals not to exceed 12 calendar months.\n\n    3. Before further flight after any Requirement 2 inspection where corrosion damage is detected.\n\nThis Airworthiness Directive becomes effective on 19 February 2004.\n\nBackground: The FAA received several reports of rudder torque tube and rib corrosion on Piper PA-31 Series aircraft. The area surrounding the rudder torque tube assembly and rudder rib does not have a means or access to inspect this area and no way for water to drain out. Corrosion in the rudder torque tube assembly and rudder rib could result in failure of the rudder torque tube, and consequent loss of rudder control.\n\n![](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 8 January 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 28 January 2004.","sortOrder":0}],"analysis":{"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":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific unsafe condition (corrosion in rudder torque tube assembly) on a defined aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single discrete safety issue addressed (corrosion in specific component)","Clear three-step requirement structure (install access, inspect, repair if needed)","Straightforward compliance timeline (150 hours, then 12-month recurring)","Limited applicability (specific aircraft models and serial number ranges)","References external technical document (Piper Service Bulletin 1105A) for detailed procedures","Cross-reference to FAA AD 2003-24-07 for repair standards","No nested conditional logic or exceptions within the regulatory text itself"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of specified Piper PA-31 series aeroplanes to modify the rudder (add or use an inspection hole) and carry out regular visual inspections of the rudder torque tube and ribs, repairing or replacing any corrosion before flight.  \n\nIt targets PA-31/Navajo/Chieftain/Cheyenne variants built 1960s–1980s to prevent trapped-water corrosion that could cause rudder torque tube failure and loss of rudder control."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive enforces inspection access, recurring inspections and remedial action for the explicitly listed PA-31 models/serial numbers to address corrosion risk. It does not expand applicability beyond those aircraft or add unrelated requirements; its effect is to mandate inspection access and corrective repairs consistent with the stated safety purpose (Applicability; Requirement; Compliance)."},"complexity_factors":["Multiple affected aircraft models and precise serial-number ranges increase identification and administrative burden (Applicability).","Mandated physical modification (install inspection hole or enlarge tooling hole) requires maintenance access and structural work (Requirement 1).","Recurring visual inspections with specific intervals (150 hours initial, then annually) impose operational scheduling and record-keeping duties (Compliance 1–2).","When corrosion is found, choice between full replacement or an approved repair design creates regulatory coordination and potential certification work (Requirement 3; FAA AD reference).","Safety-critical nature of rudder torque tube raises urgency and may lead to aircraft being grounded until compliant, increasing direct costs to operators (Background; Compliance).","Cross-reference to FAA AD introduces inter-jurisdictional compliance and reliance on external repair criteria (Note / Background)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of the listed Piper PA-31 variants and serial numbers to provide inspection access to the rudder torque tube (by installing an inspection hole or using/enlarging an existing tooling hole), visually inspect for corrosion, and replace or repair any corroded parts using an approved design. Inspections must occur within 150 flight hours and then annually; any required repairs must be completed before further flight because corrosion could cause rudder torque tube failure and loss of rudder control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-130-rudder-torque-tube-assembly-and-rudder-rib","history":"/api/acts/ad-pa-31-130-rudder-torque-tube-assembly-and-rudder-rib/history","analysis":"/api/acts/ad-pa-31-130-rudder-torque-tube-assembly-and-rudder-rib/analysis","conflicts":"/api/acts/ad-pa-31-130-rudder-torque-tube-assembly-and-rudder-rib/conflicts","importantCases":"/api/acts/ad-pa-31-130-rudder-torque-tube-assembly-and-rudder-rib/important-cases","documents":"/api/acts/ad-pa-31-130-rudder-torque-tube-assembly-and-rudder-rib/documents"}}