What are the "parts" of a SID procedure?

Question

In the ARINC 424 (downloadable from this link), the following information about SIDs procedures is given in the section 5.7 Route Type (RT TYPE):

As you can see, it appears to me that a procedure is formed by three parts. My questions are the following:

• Is a SID made from 3 parts: Runway Transition, Common Route, Enroute Transition?
• If yes, how are they related between one another? What is their order starting from the airport?
• Could you provide an example from chart that shows these 3 parts?
• Is there anything else i should consider in order to put together all the parts of a SID?

I hope my questions even make sense.

Answer 1

FAA Order 8260.46F - Departure Procedure (DP) Program describes "... the policy, guidance, and standardization for initiating, developing, processing, and managing the Departure Procedure (DP) Program."

Your questions are broad-based, but Order 8260.46F should provide the answers you are looking for.

Here are two figures from Order 8260.46F. These figures are accompanied by descriptive text and illustrate the type of information in the Order which should be responsive to your questions:

Answer 2

Yes, a SID can have three parts as you described. The runway transition defines the path from each runway to get to the common route section of the SID. All runways then share the common route section. After the common route, there may be multiple enroute transtions to get an aircraft on to the rest of its flight plan.

Below is the EPKEE RNAV departure from Denver International with the different sections labeled.

^{Chart Source: AirNav}

This is an example of a procedure with all three sections. The sections will always be in the same order, but a procedure may only have two or one of them. Note that it can be hard to tell from the graphic where the runway transtions end and the common route begins. The procedure also has a description for each runway that describes the runway transtion:

TAKEOFF RUNWAY 8: Climb heading 083° to intercept course 106° to cross KIDNG at or below 10000, then on track 106° to PIDLE, then on track 107° to cross APUUU at or above 14000, then on track 110° to VCTRE, then on track 110° to EPKEE, thence. . . .

Even though multiple runways share some sections of the runway transition, they all end at EPKEE. The procedure for Runway 25 tells pilots to expect radar vectors rather than having a defined route.

After WEEDS aircraft can choose the GATTR or DUUCE transitions, or some other waypoint, to begin the enroute section of their flight plan. The enroute transitions are also listed on the chart after the runway transitions.

Answer 3

You asked the question in terms of ARINC 424 which imposes the constraints of the database structure and use. So I'll try to explain SIDs within that constraint and in the broader sense. The reason for that is that ARINC 424 exists to support the use of an FMS (or an RNAV navigator). But some SIDs don't require an FMS to fly them. The ones that start with "SID" or Vector". FMS SIDs require and FMS (but not necessarily a modern RNAV capable FMS). RNAV SIDs require an RNAV system with the database because they use RNAV waypoints that only exist within the database. A modern RNAV FMS can use any of the SIDs.

For the more generic description of SIDs, I refer to the Instrument Procedures Handbook (FAA-H-8083-16B).

As described there and in 757toga's answer, a SID has one or more runway transitions (the start point) and a route (a sequence of fixes) to the end of the basic DP. For some SIDs, this is the enroute transition. For others, there are additional transition routes that fan out from the end of the basic DP to multiple enroute transition fixes.

Enroute transition fixes are fixes that exist in the SID and in the enroute system structure (e.g., on the Low Altitude IFR charts).

So back to what you are seeing in ARINC 424. Each of the SID routes is coded in the database starting with the Runway Transition, followed by the waypoints that define the Route and ending at the Enroute Transition.

When entering the flight plan into the FMS, you select the depart runway. You can then insert a SID. If there is more than one enroute transition, the FMS will require you to select the enroute transition. You can then add the enroute portion of your plan.

Since SIDs can cover many environments

What the FMS does with what you entered is to start the plan from a fix on the selected runway with a 'takeoff' leg, typically a FA leg (fix to an altitude) to 400 feet AGL. The FMS then 'strings' in the SID with a leg to the runway transition followed by legs to each of the fixes in the SID route until it reaches the enroute transition. While it does this it adds the altitude constraints to each of the fixes along the route. The enroute portion of the flight plan is then added.

You'll note that "Vector" SIDs only list a Runway Transition and an Enroute Transition as the route will be provided by ATC as vectors. The FMS loads these two waypoints separated by a DISCO (disconnect). It will sequence the runway transition after takeoff and then do nothing while the pilot follows the ATC vectors. When told by ATC, the pilot can clear the DISCO by entering a Direct-To leg to the Enroute Transition fix.