@base <http://semantics.aero/airspace-class>.

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix owl: <http://www.w3.org/2002/07/owl#>.
@prefix dc: <http://purl.org/dc/elements/1.1/>.
@prefix skos: <http://www.w3.org/2004/02/skos/core#>.
@prefix ac: <http://semantics.aero/airspace-class#>.

<http://semantics.aero/airspace-class> rdf:type owl:Ontology;
	dc:title "Airspace Class";
	dc:version "1.0.0";
	dc:description "A classification of airspaces as defined and applied by the US Federal Aviation Administration (FAA).";
	dc:creator "Charles Chen";
	dc:publisher "OGC Testbed 13";
	dc:source "http://docs.opengeospatial.org/per/17-036.html";
	dc:source "<a href=\"https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/media/pilot_handbook.pdf\">Chapter 15 of the FAA Pilot\'s Handbook of Aeronautical Knowledge FAA-H-8083-25B</a>";
	dc:issued "2017-09-21";
	skos:editorialNote "The source of this taxonomy is OGC Testbed 13 <a href=\"http://semantics.aero#ref-2\">Geospatial Taxonomies Engineering Report</a>. It has been modified to support a uniform approach adopted for semantics.aero";
	dc:format "RDF".

ac:airspace-class a skos:Concept;
	skos:prefLabel "Airspace Class";
	skos:altLabel "Airspace Classification";
	skos:definition "A portion of airspace defined according to the complexity or density of aircraft movements, nature of the operations conducted within the airspace, the level of safety required, and national and public interest.";
	skos:narrower ac:class-a;
	skos:narrower ac:class-b;
	skos:narrower ac:class-c;
	skos:narrower ac:class-d;
	skos:narrower ac:class-e;
	skos:narrower ac:class-f;
	skos:narrower ac:class-g;
	skos:narrower ac:sua.

ac:class-a a skos:Concept;
	skos:prefLabel "Class A Airspace";
	skos:definition "Class A Airspace is from 18,000 feet Mean Sea Level (MSL) up to and including Flight Level (FL) 600.  This includes airspace up to 12 nautical miles off the coast of the contiguous United States and Alaska.  Any space beyond the 12 nautical miles off the coast line is considered international airspace. Domestic radio navigational signal and ATC radar coverage is required to be considered Class A airspace.".

ac:class-b a skos:Concept;
	skos:prefLabel "Class B Airspace";
	skos:definition "Class B Airspace is bounded from the surface to 18,000 feet MSL surrounding major airports.  The volume of airspace for Class B is designed based on the surface area of the airport and the volume of terminal airspace controlled by the airport or terminal air traffic control center.  All aircraft require ATC clearance to operate within this airspace.  ATC manages separation of aircraft.  VFR operation may be flown if a cloud clearance is provided by ATC.".

ac:class-c a skos:Concept;
	skos:prefLabel "Class C Airspace";
	skos:definition "Class C airspace is bounded from the surface of the airport to 4,000 feet MSL.  The first layer of the airspace is from the surface area to the ceiling boundary with 5 nautical miles radius.  The second layer is from 1,200 feet MSL to the ceiling at a 10 mile radius. The outer layer extends to 20 nautical miles radius.  Class C airspace surrounds airports containing regular commercial traffic of 100 passengers per flight or more.  Class C airspaces contain an operational tower, radar-controlled approach system, and a minimum number of IFR approaches per year.".

ac:class-d a skos:Concept;
	skos:prefLabel "Class D Airspace";
	skos:definition "Class D airspace is bounded from the surface of an airport to 2,500 feet MSL.  The outer boundary radius varies but is typically 4 nautical miles. Class D airspace is classified as any airport with a functional control tower with minimal IFR approaches.  The airspace reverts to Class E or G during hours when the tower is closed or under special conditions.".

ac:class-e a skos:Concept;
	skos:prefLabel "Class E Airspace";
	skos:definition "Class E airspace is controlled airspace that is neither A, B, C, or D.  this airspace extends from 1,200 feet Above Ground Level (AGL) up to 18,000 feet MSL.  Some areas as low as 700 AGL are included and are notated in sectional charts.  Most of the airspace in the United States is class E.".

ac:class-f a skos:Concept;
	skos:prefLabel "Class F Airspace";
	skos:definition "Class F airspace is not used in the U.S. In Canada, Class F airspace is equivalent to the U.S. term, Special Use Airspace (SUA).  ICAO defines Class F airspace as a hybrid of Class E and G airspace in which ATC separation guidance is available but not required for IFR operation.".

ac:class-g a skos:Concept;
	skos:prefLabel "Class G Airspace";
	skos:definition "Class G airspace includes all airspace below 14,500 feet MSL which is not otherwise classified or controlled.  Class G airspace is considered uncontrolled airspace. This work is influenced by the OGC ISO/TC211 and GeoRSS (georss.org). This document describes examples in which RDF syntax is used for Geo and FOAF vocabularies, GML syntax for gml points, and geo-coding with RSS 1.0.".

ac:sua a skos:Concept;
	skos:prefLabel "Special Use Airspace";
	skos:altLabel "SUA";
	skos:definition "Special  Use  Airspace (SUA) or  special  area  of  operation  (SAO) is  the  designation  for  airspace  in  which  certain  activities must  be  confined,  or  where  limitations  may  be  imposed on  aircraft  operations  that  are  not  part  of  those  activities.".