About: http://webisa.webdatacommons.org/369172757

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Needs exist for apparatus that allow pilots and other aircraft personnel to receive information and instructions when visual and audible aids are not available.
http://www.w3.org/ns/prov#wasQuotedFrom	google.co.uk