Definition
A specific named Standard Instrument Departure (SID) procedure published for Birmingham-Shuttlesworth International Airport (KBHM), with the suffix 'Three' indicating it is the third revision of that named procedure. It provides a charted set of routes, altitudes, and instructions that pilots follow after takeoff to transition from the airport environment into the en route structure.
Plain English
It is the third version of a published departure route out of Birmingham. Pilots fly the printed path and altitudes after takeoff so air traffic control can move them safely from the airport into the en route airway system.
Context Anchor
Seen on a departure procedure chart and in IFR clearance or briefing discussions before departure from the Birmingham area.
Derivation
Departure procedures are named after a nearby fix, navaid, or city, followed by a number indicating the revision. 'Three' simply means this is the third published version. Each time the FAA changes the routing, altitudes, or notes, the number increments.
Why Pilots Care
Gives a standardized, obstacle-safe path that reduces workload and radio chatter during the busiest phase of flight.
Intuition Check
Do not read “Three” as three separate departures or three required steps. In this name, “Three” identifies the published version of the Birmingham Departure procedure.
Example Sentence 1
Cleared as filed, Birmingham Three Departure, then on course.
Example Sentence 2
Following the Birmingham Three Departure kept the aircraft clear of terrain during the climb in clouds.