Standard Instrument Departure

Standard instrument departure (SID) routes, also known as departure procedures (DP), are published flight procedures followed by aircraft on an IFR flight plan immediately after takeoff from an airport.

A SID is an air traffic control coded departure procedure that has been established at certain airports to simplify clearance delivery procedures. SIDs are supposed to be easy to understand and, if possible, limited to one page.

Although a SID will keep aircraft away from terrain, it is optimized for air traffic control route of flight and will not always provide the lowest climb gradient. It strikes a balance between terrain and obstacle avoidance, noise abatement (if necessary), and airspace management considerations. In order to legally fly a SID, a pilot must possess at least the current version of the SID's textual description. SIDs in the United States are created by either the military (the USAF or USN) or the FAA (which includes US Army fields). The main difference between US military and civilian SIDs is that military SIDs depict obstacles, ATC climb gradients, and obstacle climb gradients, while civilian SIDs depict only minimum obstacle climb gradients.

There are three main types of SIDs: pilot-nav SIDs, radar vector SIDs, and hybrid SIDs.

A pilot-nav SID is a SID where the pilot is primarily responsible for navigation along the SID route. It allows for the aircraft to get from the runway to its assigned route with no vectoring required from air traffic control. They are established for airports where terrain and related safety factors dictate a specific ground track be flown.

A radar vector SID is used where air traffic control provides radar navigational guidance to a filed or assigned route or to a fix depicted on a SID. Flying a vector SID may require first flying an obstacle departure procedure (ODP). This is usually annotated in the ODP section stating, "Fly runway heading to xxx prior to making any turns." Vector SIDs give air traffic control more control over air traffic routing than do pilot-nav SIDs.

A hybrid SID is a departure that combines elements of both the pilot-nav and radar vector departures. A hybrid SID usually requires the pilot to fly a set of instructions, then be vectored to a defined route to a transition to leave the terminal area.

Air traffic control clearance must be received prior to flying a SID. A SID clearance is issued to the pilot based on a combination of the destination, the first waypoint in the flight plan, and the takeoff runway used.

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