{"id":"F2006B06010","name":"AD/PA-44/4 - Throttle Cable Installation - Modification","slug":"ad-pa-44-4-throttle-cable-installation-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114408,"registerId":"commonwealth-F2006B06010-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-44/4 - Throttle Cable Installation - Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Piper PA-44 (Seminole) Series Aeroplanes\n\n \n\nAD/PA-44/4 Throttle Cable Installation - Modification 5/79\n\nApplicability: Model PA44-180 with S/Nos. 44-7995001 to 44-7995144, 44-7995146 to 44-\n\n7995180, 44-7995182 to 44-7995186, 44-7995190, 44-7995192, 44-7995193, 44-\n\n7995195 and 44-7995197.\n\n \n\nDocument: 1. Piper SB No. 639; or\n\n \n\n2. FAA AD 79-05-11, Amendment 39-3433.\n\n \n\nCompliance: Within 25 hours time in service after 5 April 1979.\n\n \n\nBackground:  There are reports of engine throttle cable breakage due to excessive spring-back induced by the present cable layout. The throttle cable support bracket is to be relocated to correct this condition.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive addressing a specific mechanical defect in specific aircraft. It has not expanded beyond its original purpose of mandating a throttle cable modification for the identified Piper PA-44 serial numbers."},"complexity_factors":["Very short document (approximately 200 words)","Only 4 defined elements: applicability (serial numbers), two reference documents, and compliance deadline","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Single, unambiguous compliance action with clear deadline","No conditional logic, exceptions, or nested provisions","Straightforward cause-and-effect: identified hazard → mandated fix → compliance timeframe"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific Piper PA-44 Seminole aircraft to **modify their throttle cable installation**. The problem is that the current cable layout causes excessive \"spring-back\" (a rebounding or snapping motion) that has led to **throttle cables breaking**. The fix involves relocating a support bracket to prevent this dangerous failure.\n\n**Who it affects:** Only specific Piper PA-44-180 aircraft with particular serial numbers (listed in the applicability section — roughly 150 individual aircraft). If you own or operate one of these specific planes, this applies to you.\n\n**Why it matters:** A broken throttle cable means you **cannot control engine power**. In a twin-engine aircraft like the Seminole, this creates a serious flight safety risk. This directive prevents potential accidents by mandating a proven fix.\n\n**What you must do:** Complete the modification within **25 hours of flight time** after 5 April 1979 (this is a historical directive, so compliance would have been required decades ago for aircraft in service at that time). The technical details are found in either Piper Service Bulletin No. 639 or the equivalent US FAA directive AD 79-05-11."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's scope is limited to relocating the throttle cable support bracket on a specific list of PA44-180 serial numbers to address reported throttle cable breakage. The instrument prescribes the corrective action and the documents to be followed and sets a specific compliance timeframe; it does not broaden applicability beyond the listed serial numbers or add other measures in the supplied text. (Applicability; Document; Compliance; Background)"},"complexity_factors":["Narrow technical scope limited to specific PA44-180 serial numbers (Applicability)","Requires following one of two external technical documents (Piper SB No. 639 or FAA AD 79-05-11) which must be obtained and followed (Document)","Short compliance window (within 25 hours time in service after 5 April 1979) creating scheduling pressure (Compliance)","Work is a mechanical modification requiring qualified maintenance personnel, parts and aircraft downtime (implied by nature of the action and Document)","No alternative compliance procedures or enforcement details included in the supplied text (Document; Compliance)"],"plain_english_summary":"# What this airworthiness directive requires\n\n- The directive requires a physical change to the throttle cable installation on certain Piper PA-44-180 (Seminole) aeroplanes. Mechanically, it mandates relocating the throttle cable support bracket (the part of the cable routing that supports the throttle cable) on the aircraft listed under \"Applicability.\" (Applicability)\n\n- The work must be done using either Piper Service Bulletin No. 639 or FAA Airworthiness Directive 79-05-11, Amendment 39-3433, as the instructions for the modification. (Document)\n\n- The modification must be completed within 25 hours time in service after 5 April 1979. (Compliance)\n\n# Why the rule was issued (official rationale)\n\n- The directive states there have been reports of engine throttle cable breakage caused by excessive spring-back from the existing cable layout; relocating the throttle cable support bracket is the prescribed fix. (Background)\n\n# Who this affects and who pays\n\n- The directive applies to specific serial numbers of the PA44-180 model aircraft listed under \"Applicability.\" Owners and operators of those aircraft are the parties who must arrange and pay for the modification. (Applicability)\n\n# Compliance burden, incentives and implementation points\n\n- Compliance burden: the owner/operator must arrange a mechanical modification performed to the instructions in one of the two referenced documents; this requires access to the specified service document(s) and qualified maintenance personnel, parts and aircraft downtime. (Document; Compliance)\n\n- Incentive to comply: the stated safety concern (reported throttle cable breakage) creates an operational incentive to perform the modification; the regulatory requirement creates a legal compliance incentive. (Background; Compliance)\n\n- Discretion and alternatives: the directive directs compliance by following one of the two specified documents; the supplied text does not state any alternative compliance methods or approvals. (Document)\n\n# Trade-offs, costs and effects on private choice\n\n- Costs are borne by the aircraft owners/operators of the listed serial numbers and take the form of labour, possible parts and aircraft downtime. (Applicability; Compliance)\n\n- Benefits are concentrated to those same owners/operators in the form of the remedial change intended to reduce the risk of throttle cable breakage. (Background)\n\n- Opportunity costs include the maintenance hours and any commercial disruption while the aircraft is out of service for the modification. (Compliance)\n\n# Implementation risk and enforcement context\n\n- The directive sets a short, specific compliance window (25 hours time in service after the stated date), which concentrates the timing risk on operators who must schedule the work promptly. (Compliance)\n\n- The supplied text does not include details about enforcement actions, extensions, or alternative means of compliance. (Document; Compliance)\n\nOverall, the instrument mechanically prescribes a single, defined maintenance modification for a narrowly specified set of aircraft, cites the documents to be used for the work, and establishes a specific short compliance window. (Applicability; Document; Compliance; Background)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-44-4-throttle-cable-installation-modification","history":"/api/acts/ad-pa-44-4-throttle-cable-installation-modification/history","analysis":"/api/acts/ad-pa-44-4-throttle-cable-installation-modification/analysis","conflicts":"/api/acts/ad-pa-44-4-throttle-cable-installation-modification/conflicts","importantCases":"/api/acts/ad-pa-44-4-throttle-cable-installation-modification/important-cases","documents":"/api/acts/ad-pa-44-4-throttle-cable-installation-modification/documents"}}