About: http://webisa.webdatacommons.org/390413205

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	A receiver located in the flight deck has an audible and visual alarm that alerts the flight crew, who can actuate a radio to transmit to ground an alert signal, for example a hijacking code, on a pre-selected frequency.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com.au