{"id":"F2006B10843","name":"AD/INST/4 Amdt 1 - Vacuum Pump Splined Coupling - Replacement","slug":"ad-inst-4-amdt-1-vacuum-pump-splined-coupling-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56331,"registerId":"commonwealth-F2006B10843-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/INST/4 Amdt 1 - Vacuum Pump Splined Coupling - Replacement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nInstruments and Automatic Pilots\n\nAD/INST/4\n\nAmdt 1\n\n  \nVacuum Pump Splined Coupling \\- Replacement 10/69\n\nApplicability: All Airborne Mechanisms vacuum pump Models 113A5 and 113A8 S/Nos. 7G2494 thru 7G2678, 8G2679 thru 8G2892, 9G2893 thru 9G3250 and 10G3251 thru 10G3714 and all vacuum pumps 113A1, 113A2, 113A5 and 113AS in which the splined drive coupling, Airborne Mechanisms P/N B1001-A2, has been replaced after July 22, 1963.\n\nRequirement: 1. Piper Aircraft: Replace all vacuum pump splined couplings identified in Piper SB No. 218 in accordance with that SB.\n\n2. Other Aircraft: Inspect all Airborne Mechanisms P/N B1001-A2 couplings for a bright yellow band on the shoulder of the coupling. Band is visible through opening in pump base. Replace all couplings not marked with couplings that are so marked. (F.A.A. AD 64-1-1 refers).\n\nCompliance: Before installation in an aircraft after 21 November 1969.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text sets a clear scope limited to specified Airborne Mechanisms vacuum pump models, listed serial-number ranges, and any pumps in which P/N B1001-A2 was replaced after 22 July 1963 (Applicability). The directive prescribes replacement procedures for Piper aircraft per Piper SB No. 218 and a visual-inspect-and-replace rule for other aircraft (Requirement 1 & 2). The instrument is labelled as an amendment (Amdt 1) but the provided text does not show any expansion or narrowing of applicability beyond the specific models, serial numbers and post-1963 replacements identified; there is no textual indication in this extract that the scope has been changed from any prior version."},"complexity_factors":["Specific parts and serial-number ranges are listed, requiring cross-checking of equipment (Applicability).","Two distinct compliance routes: a prescriptive replacement route for Piper aircraft (requires following Piper SB No. 218) and a simpler visual-inspection-and-replace route for other aircraft (Requirement 1 & 2).","Reliance on external documents (Piper Service Bulletin No. 218 and FAA AD 64-1-1) for procedural detail increases practical complexity for implementers (Requirement 1; Requirement 2 parenthetical).","The visual conformity marker (bright yellow band visible through pump base opening) is a low-technology test but can create ambiguity if the mark is obscured or altered (Requirement 2).","Compliance timing tied to installation events rather than flight hours or calendar time, which affects when operators must act (Compliance)."],"plain_english_summary":"This AD mandates that Airborne Mechanisms P/N B1001‑A2 splined couplings in specified 113A-series vacuum pumps (and any pumps where that coupling was replaced after 22 Jul 1963) be replaced or inspected and, if unmarked, replaced before the pump is installed in an aircraft after 21 Nov 1969. Piper aircraft must follow Piper SB No. 218; others inspect for a bright yellow band visible through the pump base and replace couplings without it. It’s a mandatory airworthiness maintenance requirement imposing parts, labor, and downtime costs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a narrow, targeted airworthiness directive addressing a specific mechanical defect in specific vacuum pump models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined model ranges (Piper vs Other Aircraft)","Simple conditional logic: if Piper → follow SB 218; if Other → check for yellow band → replace if absent","Single cross-reference to FAA AD 64-1-1 (informational only)","No nested exceptions or complex definitions","Clear applicability criteria based on serial number ranges and date thresholds"],"plain_english_summary":"This is a **safety directive** issued by Australia's Civil Aviation Safety Authority (CASA) that requires aircraft owners and mechanics to replace specific faulty parts in certain vacuum pumps used in aircraft instruments.\n\n**What it does:**\n- Targets **Airborne Mechanisms vacuum pumps** (specific models 113A5, 113A8, and others) with particular serial numbers, plus any pumps where a specific coupling part (P/N B1001-A2) was replaced after July 22, 1963.\n- **For Piper aircraft:** Replace the splined couplings exactly as instructed in Piper Service Bulletin No. 218.\n- **For all other aircraft:** Check the coupling for a **bright yellow band** visible through the pump base. If there's no yellow band, replace the coupling with one that has the band.\n\n**Who it affects:**\n- Aircraft owners and operators using the specified vacuum pump models\n- Aircraft maintenance engineers and mechanics\n- Essentially anyone responsible for maintaining aircraft with these particular instrument vacuum pumps\n\n**Why it matters:**\nThe splined coupling in these pumps was apparently defective or prone to failure. Vacuum pumps are critical for powering flight instruments (like artificial horizons and directional gyros). A failed coupling could cause instrument failure, potentially leading to loss of control or navigation capability—especially dangerous in poor visibility. This directive prevents accidents by ensuring only properly marked, safe couplings remain in service.\n\n**Compliance deadline:** Before installing any affected pump in an aircraft after November 21, 1969."}},"importantCases":[],"_links":{"self":"/api/acts/ad-inst-4-amdt-1-vacuum-pump-splined-coupling-replacement","history":"/api/acts/ad-inst-4-amdt-1-vacuum-pump-splined-coupling-replacement/history","analysis":"/api/acts/ad-inst-4-amdt-1-vacuum-pump-splined-coupling-replacement/analysis","conflicts":"/api/acts/ad-inst-4-amdt-1-vacuum-pump-splined-coupling-replacement/conflicts","importantCases":"/api/acts/ad-inst-4-amdt-1-vacuum-pump-splined-coupling-replacement/important-cases","documents":"/api/acts/ad-inst-4-amdt-1-vacuum-pump-splined-coupling-replacement/documents"}}