Definition
A continuous broadcast service, formerly transmitted over selected VOR frequencies, that provided pilots in flight with recorded summaries of significant weather hazards such as AIRMETs, SIGMETs, Convective SIGMETs, Center Weather Advisories, severe weather forecast alerts, and urgent pilot reports. HIWAS was discontinued by the FAA in January 2020; its function is now served by Flight Information Service-Broadcast (FIS-B) and direct contact with Flight Service.
Plain English
A radio broadcast pilots could tune in while flying to hear a recorded summary of dangerous weather in the area. It has been retired, but pilots still see it referenced in older charts, handbooks, and study materials.
Context Anchor
You may see HIWAS discussed in instrument flying weather-information sections or on older chart and radio navigation references.
Derivation
The name is plainly descriptive: a broadcast service that advises pilots, while in flight, about hazardous weather. Knowing this helps the reader recognize the term as a one-way information service rather than a two-way radio function.
Why Pilots Care
Gives pilots direct access to weather hazard updates without needing to request them from ATC or break radio silence.
Intuition Check
HIWAS is not the hazardous weather itself. It is the broadcast service that carried warnings about hazardous weather.
Example Sentence 1
The instrument textbook explained that pilots once monitored HIWAS on a nearby VOR to hear summaries of hazardous weather along the route.
Example Sentence 2
HIWAS allowed the crew to learn about icing conditions ahead and plan a safer route.