{"id":"F2006B02782","name":"AD/B727/79 - Static Sensing Holes - Modification","slug":"ad-b727-79-static-sensing-holes-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42124,"registerId":"commonwealth-F2006B02782-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/79 - Static Sensing Holes - 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)  Boeing 727 Series Aeroplanes\n\n \n\nAD/B727/79  Static Sensing Holes - Modification 6/77 Applicability:              All model B727-100 and -200 aircraft with static sensing holes of .047 inch diameter. Document:               1. FAA AD 77-02-02; or\n\n2. Boeing SB No. 727-34-94.\n\n \n\nCompliance: Within 3000 hours time in service after 30 June 1977.\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\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text sets a clear, specific scope: modify static sensing holes on all B727-100 and -200 aircraft with 0.047 inch holes, using either FAA AD 77-02-02 or Boeing SB 727-34-94, within a 3,000-hour window after 30 June 1977 (Applicability; Document; Compliance). The instrument itself contains no statement indicating a change from a prior or different scope; therefore there is no evidence in the supplied text that the scope has been altered from its original stated terms."},"complexity_factors":["Narrow technical scope limited to static sensing holes on specific Boeing 727 models (Applicability)","Precise measurement-based trigger (0.047 inch hole diameter) requires inspection and verification (Applicability)","Cross-reference to external technical documents for methods (FAA AD 77-02-02; Boeing SB No. 727-34-94) increases procedural dependence on other texts (Document)","Fixed hours-based compliance window (3,000 hours after 30 June 1977) requires operational scheduling and recordkeeping (Compliance)","Limited regulatory discretion in the AD text—operator must comply but may choose between referenced methods (Document)","Potential supply-chain and maintenance coordination issues tied to parts, tooling and downtime (implied by required modification and compliance timeframe)"],"plain_english_summary":"This Airworthiness Directive mandates a physical modification of 0.047‑inch static sensing holes on all Boeing 727‑100 and 727‑200 aeroplanes, to be completed within 3,000 flight hours after 30 June 1977. Operators must carry out the work at their expense and may comply by following either FAA AD 77‑02‑02 or Boeing Service Bulletin No. 727‑34‑94. It affects maintenance planning, downtime and parts costs for affected operators."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on static sensing hole modifications for Boeing 727 aircraft. It has not expanded beyond its original technical safety purpose. The scope remains tightly constrained to the specific airframe model and the specific instrument system identified in the original 1977 issuance."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined technical references (FAA AD and Boeing Service Bulletin)","Single, unambiguous compliance condition (time-in-service deadline)","No nested exceptions, conditional logic, or cross-references to other legislation","Clear applicability criteria (specific aircraft models + specific hole diameter)","Binary compliance pathway (either document 1 OR document 2)"],"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) that requires specific repairs or modifications to aircraft.\n\n**What it does:** It orders owners and operators of certain **Boeing 727 aircraft** (both the -100 and -200 models) to modify the **static sensing holes** on their planes. These are small openings on the aircraft's exterior that feed air pressure data to flight instruments (like altimeters and airspeed indicators). The holes must be a specific size — **0.047 inch diameter** — to trigger this requirement.\n\n**The fix:** Operators must follow one of two approved technical documents to make the modification:\n- A US Federal Aviation Administration directive (FAA AD 77-02-02), **or**\n- Boeing Service Bulletin 727-34-94\n\n**The deadline:** The work must be completed **within 3,000 flight hours** after 30 June 1977.\n\n**Why it matters:** Incorrect static pressure readings can cause pilots to receive wrong altitude or airspeed information — a serious flight safety risk. This directive ensures all affected Australian-registered Boeing 727s were modified to prevent instrument errors.\n\n**Who it affects:** Airlines, charter operators, or private owners operating Boeing 727-100 or -200 series aircraft in Australia with the specified static sensing hole configuration."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-79-static-sensing-holes-modification","history":"/api/acts/ad-b727-79-static-sensing-holes-modification/history","analysis":"/api/acts/ad-b727-79-static-sensing-holes-modification/analysis","conflicts":"/api/acts/ad-b727-79-static-sensing-holes-modification/conflicts","importantCases":"/api/acts/ad-b727-79-static-sensing-holes-modification/important-cases","documents":"/api/acts/ad-b727-79-static-sensing-holes-modification/documents"}}