{"id":"F2006B03553","name":"AD/BAL/15 Amdt 1 - Altimeter Graduations","slug":"ad-bal-15-amdt-1-altimeter-graduations","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43120,"registerId":"commonwealth-F2006B03553-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAL/15 Amdt 1 - Altimeter Graduations","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)  Hot Air Balloons\n\n \n\n# AD/BAL/15\n\nAmdt 1\n\nApplicability: All hot air balloons.\n\n# Altimeter Graduations 2/96\n\n \n\nRequirement: (a) Check that the height scale of altimeters, installed in compliance with the operational requirement of Civil Aviation Orders Section 20.18, are graduated in increments of not more than 100 feet.\n\n \n\n(b)     Check the barometric scale of sensitive altimeters to ensure they are calibrated in millibars and increments of not more than 2 millibars.\n\n \n\n(c)      Replace any altimeter that fails either or both checks.\n\n \n\nNote: Millibars are equivalent to hectopascals.\n\n \n\nCompliance: Prior to 28 March 1996 unless previously accomplished in accordance with AD/BAL/15, or\n\n \n\nPrior to issue of a Certificate of Airworthiness.\n\n \n\nBackground: Reports have been received of altimeters calibrated in metres being supplied for Balloon use. As all aircraft altitudes and airways clearances are provided in feet, and barometric scale settings are stated as millibars, this Directive is issued to require that altimeters installed in balloons are calibrated in appropriate units.\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 narrow, technical safety directive focused specifically on altimeter calibration for hot air balloons. It has not expanded beyond its original purpose of ensuring compatible measurement units for balloon altimeters."},"complexity_factors":["Very short document (under 300 words)","Only 3 simple requirements (a, b, c) with no sub-paragraphs","Single defined term implicitly handled ('sensitive altimeters' used without formal definition)","No cross-references to other legislation beyond a mention of Civil Aviation Orders Section 20.18","Simple alternative compliance pathway (two 'prior to' dates)","One explanatory note (millibars/hectopascals equivalence)"],"plain_english_summary":"This Airworthiness Directive requires all Australian hot‑air‑balloon altimeters to be checked and, if non‑compliant, replaced so altitude displays read in feet (markings ≤100 ft) and pressure settings show millibars/hectopascals (markings ≤2 mbar).\n\nIt affects balloon owners, operators and maintenance engineers. It was issued because some altimeters were in metres, risking misreadings and collisions; compliance was required by 28 March 1996 or before issuance of a Certificate of Airworthiness."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This instrument is labelled an amendment (Amdt 1) and imposes explicit unit and graduation standards for altimeters on all hot‑air balloons and a mandatory replacement rule for non‑compliance, together with a compliance deadline or linkage to Certificate of Airworthiness. Mechanically, it converts a previously less‑specified requirement into a time‑bound, equipment‑specific obligation and thereby makes the technical and financial responsibilities of operators explicit."},"complexity_factors":["Clear numerical thresholds (≤100 ft for height graduations; ≤2 millibars for barometric increments) reduce interpretive ambiguity.","Applies to all hot air balloons (broad, uniform scope) so many owners/operators are affected.","Technical verification requires inspection/calibration capability or specialist service to confirm increments and units.","Mandatory replacement for non‑compliant instruments imposes a direct cost on operators.","Compliance is time‑bound (before 28 March 1996) or tied to Certificate of Airworthiness, creating a hard administrative deadline.","Reference to 'sensitive altimeters' and unit equivalence (millibars = hectopascals) introduces limited technical terminology that may require clarification for some inspectors."],"plain_english_summary":"This amendment requires all hot‑air balloon altimeters to display height in steps of no more than 100 feet and for sensitive (barometric) altimeters to show pressure in millibars with steps no greater than 2 millibars; any altimeter that fails these checks must be replaced. It applies to every hot‑air balloon and must be complied with before 28 March 1996 or before a Certificate of Airworthiness is issued, shifting inspection and replacement costs to balloon operators to align instrument units with aircraft altitude and pressure conventions."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-bal-15-amdt-1-altimeter-graduations","history":"/api/acts/ad-bal-15-amdt-1-altimeter-graduations/history","analysis":"/api/acts/ad-bal-15-amdt-1-altimeter-graduations/analysis","conflicts":"/api/acts/ad-bal-15-amdt-1-altimeter-graduations/conflicts","importantCases":"/api/acts/ad-bal-15-amdt-1-altimeter-graduations/important-cases","documents":"/api/acts/ad-bal-15-amdt-1-altimeter-graduations/documents"}}