{"id":"F2006B10281","name":"AD/GENERAL/50 - Whelen Strobe Light - Modification","slug":"ad-general-50-whelen-strobe-light-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55970,"registerId":"commonwealth-F2006B10281-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GENERAL/50 - Whelen Strobe Light - Modification","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAircraft \\- General\n\nAD/GENERAL/50 Whelen Strobe Light \\- Modification 4/75\n\nApplicability: All aircraft equipped with Whelen A427 strobe light flash tubes manufactured before 1 November 1974.\n\nRequirement: Install on the base of Whelen Engineering Company Incorporated A427 strobe light flash tubes a pressure sensitive-vinyl label conforming to Whelen Engineering Company Incorporated Drawing A-300052, Revision 1, dated October 15, 1974, or a strip of Scotch Brand Type 33 vinyl plastic electrical tape can be used in lieu of the vinyl label. If the vinyl plastic electrical tape is used, it must be formed to cover the rivet at the rear of the flash tube without covering the identifying part number. If the flash tube incorporates a label, the new label or tape may be installed directly over the old label.\n\nNote: To ensure proper adhesion install the label or tape only when the label or tape and the flash tube are at a temperature above 10 degrees C.\n\nCompliance: Within the next 100 hours time in service after 30 May 1975.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific component defect. It has not expanded beyond its original purpose of mandating a physical modification to early-model Whelen strobe lights."},"complexity_factors":["Single, specific applicability criterion (manufacturing date cutoff)","One primary requirement with one explicit alternative permitted","Single condition on the alternative (tape must cover rivet but not part number)","One additional permissive provision (overlay allowed if label already present)","Single operational note regarding temperature for adhesion","Clear compliance deadline with objective trigger (hours time in service)","No defined terms section, no cross-references to other legislation, no nested exceptions"],"plain_english_summary":"This CASA Airworthiness Directive mandates that owners/operators of Whelen A427 strobe flash tubes manufactured before 1 Nov 1974 fit a pressure‑sensitive vinyl label (or Scotch Type 33 vinyl electrical tape as an allowed alternative) over the tube base so the rear rivet is covered but the part number remains visible. \n\nThe fix—installable over existing labels and to be applied above 10°C—addresses a potential integrity/safety issue; compliance was required within 100 flight hours after 30 May 1975."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive does not broaden regulatory coverage; it imposes a narrowly tailored modification on an already identified set of components (Whelen A427 flash tubes pre-1 Nov 1974) and sets a specific compliance method and timeframe (Applicability, Requirement, Compliance). Responsibility for compliance and associated costs falls on aircraft owners/operators; no new enforcement powers or wider obligations are created by this instrument."},"complexity_factors":["Narrow applicability — targets only Whelen A427 strobe flash tubes manufactured before 1 November 1974 (Applicability).","Prescriptive materials/specification — requires Whelen Drawing A-300052 Revision 1 or Scotch Brand Type 33 tape as an alternative (Requirement).","Installation constraint — tape must cover the rear rivet without obscuring the identifying part number; new label may overlay old label (Requirement).","Environmental condition for effective installation — label or tape and flash tube must be above 10°C to ensure adhesion (Note).","Clear, short compliance window — within next 100 hours time in service after 30 May 1975 (Compliance).","Low technical difficulty but transfers cost/responsibility to aircraft owners/operators to procure materials and perform the installation (Requirement & Compliance)."],"plain_english_summary":"This Airworthiness Directive orders a simple physical modification to Whelen A427 strobe flash tubes made before 1 November 1974: fit a pressure‑sensitive vinyl label (per Whelen Drawing A‑300052 Rev 1) or use a strip of Scotch Type 33 vinyl electrical tape so the rear rivet is covered but the part number remains visible. Installation must be done at temperatures above 10°C and within 100 hours time in service after 30 May 1975. It applies to owners/operators of aircraft fitted with those flash tubes."}},"importantCases":[],"_links":{"self":"/api/acts/ad-general-50-whelen-strobe-light-modification","history":"/api/acts/ad-general-50-whelen-strobe-light-modification/history","analysis":"/api/acts/ad-general-50-whelen-strobe-light-modification/analysis","conflicts":"/api/acts/ad-general-50-whelen-strobe-light-modification/conflicts","importantCases":"/api/acts/ad-general-50-whelen-strobe-light-modification/important-cases","documents":"/api/acts/ad-general-50-whelen-strobe-light-modification/documents"}}