Definition
A direction-of-flight notation indicating travel toward the south. Used in flight plans, NOTAMs, ATC communications, and route descriptions to specify that an aircraft, route, or traffic flow is heading in a southerly direction.
Plain English
Going south. SB is just shorthand for an aircraft or route heading in a southerly direction.
Context Anchor
Seen in FAA notices, airport information, and other short aviation text where space is limited.
Derivation
Southbound combines “south” with “bound,” meaning headed toward a place or direction. Here, it means headed toward the south, not “bound” as in tied up.
Why Pilots Care
Correct understanding prevents misreading of directional restrictions and routing instructions.
Intuition Check
SB does not mean “stand by” in this FAA abbreviation context. Here, SB means southbound: toward the south.
Example Sentence 1
The NOTAM advised that the SB lane of the airway was closed for military activity.
Example Sentence 2
The NOTAM advised SB traffic to expect delays.