Assertion: beacon | /r/HasProperty | unreliable
Facets:
value: for navigation
type: PURPOSE
Source sentences:
text: If an NDB has a problem, e.g. lower than normal power output, failure of mains power or standby transmitter is in operation, the NDB may be programmed to transmit an extra 'PIP' (a Morse dot), to alert pilots and others that the beacon may be unreliable for navigation.