At many busy controlled airports, specific Standard Instrument
Departures (SID), now referred to as Departure Procedures
(DPs), are published to expedite clearance delivery and to facilitate
transition between takeoff and enroute operations. The SID provides
a standard route from the terminal to the enroute structure. There
are often transitions which connect the end of the SID with one
of several enroute possibilities.
SIDs furnish pilots departure routing clearance information in
graphic and textual form. This simplifies the issuance of a departure
clearance by allowing ATC to simply specify the SID by name without
having to describe, in detail, the route. The clearance may include
the basic SID name and number, plus a transition to the enroute
portion of the flight plan.
For example, without the SIDs and filing a flight plan from St.
Louis Lambert International and heading north, your clearance might
be something like the following:
"Lear123 cleared direct STL VORTAC then via STL radial 014 to SKUTR
intersection, then via BDF radial 198 to BDF VORTAC. Fly runway
heading for vectors. Climb and maintain 2500 feet, expect clearance
to filed altitude 10 minutes after departure."
The controller not only has to read this to you, but, you have
to copy it and read it back!
If you had the SID for the CARDS FOUR Departure (see below) and
filed that in your flight plan, the entry would be CARDS4.BDF. This
indicates to ATC that you plan to fly the CARDS FOUR SID and use
the BRADFORD Transition. Each SID will usually have several transitions
available to help you get started in the direction you plan to fly.
Your clearance for the first part of the trip would probably be:
"Lear123 cleared via CARDS FOUR, BRADFORD TRANSITION." This not
only saves air time, it saves a lot of hassle on your part since
you have a chart in front of you with all the necessary information.
In order to file a SID, you are required to either have the graphical
or textual representation of the SID.
On the chart below, the Bradford transition is highlighted in red.
As you can see, the SID starts at the departure runway, then via
radar vectors to the STL VORTAC. At this point, the pilot would
be expected to navigate to the SKUTR intersection via the 014° radial
and then on to BDF VORTAC via the 198° radial.
In addition to the departure procedures themselves, there is a
lot of other information on the SID, such as (A) the name
of the facility and the SID, (B) frequencies for communications,
(C) navigation aids, including frequencies and identifiers,
(D) minimum altitudes, distances and courses, and (E)
text descriptions of the procedures and transitions.
SIDs are designed to separate departing traffic from arrivals,
provide efficient interception of an outbound course, avoid noise
sensitive areas, simplify the issuance of departure clearances,
and reduce radio traffic.
There are two basic types of SIDs: pilot navigation, where the
pilot is primarily responsible for navigation along the SID course,
and vector SIDs, where ATC will provide radar vectors to an assigned
route or fix.
If you do not want to fly a SID, a note should be entered in the
remark section of the flight plan indicating "no SID".