{"id":"F2006B04023","name":"AD/BEECH 55/78 - Fuel Crossfeed Check Valves","slug":"ad-beech-55-78-fuel-crossfeed-check-valves","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43632,"registerId":"commonwealth-F2006B04023-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 55/78 - Fuel Crossfeed Check Valves","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)  Beechcraft 55, 58 and 95-55 (Baron) Series Aeroplanes\n\n \n\nAD/BEECH 55/78 Fuel Crossfeed Check Valves 5/93\n\nApplicability: All model 58 and 58A aircraft with serial numbers TH-1488, TH-1600, TH-1613 thru TH-1635 and TH-1638 thru TH-1662.\n\n \n\nRequirement: Action in accordance with Beech mandatory SB No 2454.\n\n \n\nNote: FAA AD 93-01-23 Amdt 39-8477 refers.\n\n \n\nCompliance: As specified in the requirement document with a revised effective date of 16 April 1993.\n\n \n\nBackground: Due to possible fuel pressure build up in the cross feed valves, caused by increased temperature, several operators have reported that excessive force was required to operate the fuel selector valve.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive applies only to the specific Model 58 and 58A serial numbers listed in the Applicability section and requires compliance with Beech mandatory SB No. 2454. The text does not indicate any expansion or narrowing of that scope beyond the listed serial numbers; the only temporal adjustment noted is a revised effective date of 16 April 1993 (Compliance section)."},"complexity_factors":["Narrow, serial-number limited applicability (only specified Model 58/58A serial numbers) (Applicability section)","Delegation of technical detail to an external document (Beech mandatory SB No. 2454) rather than specifying tasks in the AD itself (Requirement section)","Reference to an external, related foreign AD (FAA AD 93-01-23) which may be relevant for context but does not change the mandated action here (Note section)","A revised effective date that operators must observe (Compliance section)","Technical subject matter (fuel crossfeed check valves) requires maintenance expertise to implement, increasing practical compliance complexity despite simple regulatory text (Background and Requirement sections)"],"plain_english_summary":"This airworthiness directive makes compliance with Beech Mandatory Service Bulletin No. 2454 compulsory for certain Beechcraft Baron Model 58 and 58A aeroplanes (specified serial numbers) to address fuel crossfeed/check‑valve pressure build‑up that can make the fuel selector hard to operate. \n\nOwners/operators of the listed aircraft must carry out and pay for the SB work by the AD’s effective date (16 April 1993); the AD delegates the specific technical steps and timing to the referenced service bulletin."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in defined aircraft. It has not expanded beyond its original purpose of mandating a valve inspection/repair."},"complexity_factors":["Single, specific applicability clause limited to defined serial number ranges","Single requirement referencing external technical document (Beech SB 2454)","No defined terms section — uses plain aircraft terminology","No conditional logic, exceptions, or nested provisions","Minimal cross-referencing (one FAA AD reference in a note only)","Short document (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of certain Beechcraft Baron aeroplanes (models 58 and 58A with specific serial numbers) to inspect and fix a problem with their **fuel crossfeed check valves**.\n\n**The safety issue:**\nWhen fuel gets hot, pressure can build up in the crossfeed valves (which let fuel flow between tanks). This makes the fuel selector valve very hard to turn — potentially dangerous in flight if a pilot needs to switch fuel tanks quickly.\n\n**What must be done:**\nFollow the instructions in **Beechcraft Service Bulletin No. 2454** — a technical repair notice from the manufacturer. The US Federal Aviation Administration (FAA) has issued a matching directive (AD 93-01-23), so this aligns Australian requirements with American safety standards.\n\n**Who it affects:**\nOwners and operators of specific Beechcraft Baron aircraft built in the late 1970s/early 1980s (serial numbers TH-1488, TH-1600, TH-1613 through TH-1635, and TH-1638 through TH-1662).\n\n**Why it matters:**\nIf pilots can't switch fuel tanks easily during flight, they could lose engine power or have to make emergency landings. This directive prevents that by ensuring the valves work smoothly even when fuel is hot."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-55-78-fuel-crossfeed-check-valves","history":"/api/acts/ad-beech-55-78-fuel-crossfeed-check-valves/history","analysis":"/api/acts/ad-beech-55-78-fuel-crossfeed-check-valves/analysis","conflicts":"/api/acts/ad-beech-55-78-fuel-crossfeed-check-valves/conflicts","importantCases":"/api/acts/ad-beech-55-78-fuel-crossfeed-check-valves/important-cases","documents":"/api/acts/ad-beech-55-78-fuel-crossfeed-check-valves/documents"}}