Departure Procedure

A Departure Procedure (DP) is a published instrument flight procedure that provides obstacle clearance and a standardized routing from the departure airport to the en-route airway structure. There are two main types:

• SID (Standard Instrument Departure): An ATC-assigned departure route designed primarily for traffic management and noise abatement. SIDs use specific waypoints, altitude restrictions, and speed constraints to sequence departing traffic efficiently
• ODP (Obstacle Departure Procedure): Designed solely to provide obstacle clearance in the departure path. ODPs are typically used when terrain or obstacles near the airport require a specific climb gradient or routing to ensure safe departure

SIDs may be conventional (using ground-based navaids like VOR/DME) or RNAV-based (using GPS waypoints). Modern RNAV SIDs allow more precise routing, reducing track miles and fuel burn while maintaining safe separation from terrain and other traffic.