Plain English Meaning

A free phone number pilots in the U.S. can call to talk to a weather briefer, file a flight plan, or get other flight planning help.

Full Definition

The toll-free telephone number used in the United States to reach a Flight Service Station (FSS) for preflight weather briefings, flight plan filing, and other pilot services provided by Flight Service.

Context Anchor

Seen in FAA material about Flight Service Stations and preflight weather briefings.

Derivation

The letters WX are the long-standing aviation and meteorology shorthand for ',' and BRIEF refers to the receives. The number spells its purpose on a telephone keypad.