Reading Standard Instrument Depatures (SIDs) and Standard Terminal Arrival Route Charts (STARs)
Information in this section contributed by Andrew Podner.
SIDs and STARs are preplanned routes to help efficiently get traffic into and out of the Terminal Area, the area in the vicinity of an airport. In busier airspaces, these routes are used to increase efficiency ans safety while decreasing workload on pilots and controllers. This is accomplished by providing as much information as possible to the pilot on the chart to reduce the number of instructions that an ATC will have to give. For ATCs it makes traffic management much simpler as aircraft are flying on more predictable routes.
Leaving the Terminal Area
SIDs (also called DPs) facilitate traffic departing the airspace. SID stands for "Standard Instrument Departure". These procedures come in a few different types, but they all serve the same general purpose.
Radar Vector Departure
A Radar Vector SID is one of the simplest procedures to fly and provide ATC for. At the core, a Radar Vector departure is one in which the ATC is always expected to provide a vector to the pilot to put them onto their filed route. There are no transitions on a Radar Vector SID, and any waypoint or VOR shown on the chart is essentially there for reference. Sometimes the graphic or 'map' part of the SID is a little overwhelming to look at, but the narrative portion is usually fairly straightforward and will help you understand the chart better.
Letâ€™s use the Memphis Seven (MEM7) Departure as an Example:
The DEPARTURE DESCRIPTION tells us that the pilot should climb via Runway Heading or as assigned and expect a vector onto the filed route. It also tells the pilot not to make any turns until passing an altitude of 700 feet.
Additionally, it tells us that the initial altitude for Turbojets is 5,000 feet and it is 3,000 feet for props unless otherwise assigned by ATC, and that they pilot can expect clearance to cruise altitude ten minutes after departure.
The graphical part of the SID gives us some additional information. It tells us what the ATIS frequency, Clearance Delivery Frequency, and Departure Frequencies are. It also gives us several VORs as points of reference. Since many positions are combined on VATSIM, these frequencies may be different than what is in use on the network.
In practice, a pilot filing the MEM7 Departure will takeoff flying runway heading while climbing toward 5,000 feet and will be expecting the departure controller to issue a radar vector (heading) toward the filed route.
Hybrid Standard Instrument Departures
Another type of SID which is more complex, but still very easy to understand is a Hybrid SID. If you recall from the S1 Section Introduction to Clearance Delivery a "Hybrid" Departure is one that combines elements of both the Radar Vectored departure, and a Pilot Nav departure. This type of departure provides for an aircraft to first fly a set of headings/instructions, then to be vectored to a defined route to exit the terminal area on a â€˜transitionâ€™. The transition is a point at which the pilot leaves the SID and joins the en-route portion of their flight plan. For instance, on the Dallas Eight or (DALL8) departure below, the SID can start at the Maverick VOR (TTT) and end at one of several points such at Little Rock VOR (LIT), Meridian VOR (MEI), etc.
This type of departure is more specific and gives detailed headings and distances to fly to go from the beginning to the end of the SID. Let's look at the graphical and narrative portion of this departure procedure:
Let's start by looking at the graphical portion of this chart.
In this portion of the chart, the pilot flies from POTEN intersection to TEKBE intersection. The chart gives us the exact location of each intersection. On the line connecting the waypoints, we find the heading that must be flown to get from POTEN to TEKBE. The number below the heading in parenthesis is the distance between the waypoints in nautical miles, 44 in this case. The number above the heading is the minimum altitude required to be flown for the segment, 10,000 in this case.
The number pointing toward POTEN, 94, is a reference distance to a VOR. If we look at the larger chart, we see that the Belcher VOR (EIC) is opposite this arrow, and is at a distance of 94nm from POTEN.
The final piece of information, R-346, is another reference that tells us what radial of a VOR that a waypoint lies on. In this case, the chart is telling us that TEKBE lies on the 346 outbound radial of the Gregg County VOR (GGG).
Now letâ€™s look at the narrative portion:
This SID is much more specific in terms of what the pilot is expected to do. In this case, assuming the pilot is departing on runway 35L, he or she is expected to fly heading 360 on takeoff until 7.3 NM from the Maverick VOR (TTT), at which point they should turn to a heading of 005. From there, the pilot will expect a vector to the filed route, which could be a vector to intercept the route somewhere between two waypoints, or it could also be a vector to fly direct to a waypoint and then resume the departure.
From reading the chart we also learn that the initial climb is 10,000 feet. The pilot will expect their filed altitude 10 minutes after departure and also is instructed to fly at 230 kts IAS until passing 5,000 feet.
There are also other specific instructions depending on which transition the pilotâ€™s route is filed with that will give more details about how to get to the transition.
Each departure procedure is unique with specific instructions and it is very helpful for both pilots and ATCs to understand what is expected from each so that traffic flow is as efficient as possible.
Pilot-Nav Departure Procedures
The final type of departure procedure is that of a pilot-nav departure procedure. A Pilot Nav departure is one that will allow the aircraft to get from the runway, to their assigned route with no vectoring required from the Air Traffic Controller. A lot of Pilot Nav departure procedures are RNAV (through its important to note that not all are).
RNAV stands for Area Navigation and conceptually, RNAV is the use of GPS technology to fly a particular route.
To fly RNAV departure, specific equipment requirements exist to ensure that the aircraft can correctly fly the procedure. Typically a GPS or DME equipment is required. An FMC or Flight Management Computer is also used for this. This is a good example of why aircraft equipment suffixes are important. If an aircraft does not have the proper equipment, it cannot fly an RNAV departure.
Looking at the Clare Two (CLARE2) departure, we see that there are very exact headings given from the runway all the way to the transition. This cuts down on ATC workload, and in practice, an ATC will probably only have to do 3 things with an aircraft on an RNAV departure.
First, ATC will radar identify the aircraft, as he or she would with any departure. Then ATC will at some point issue a climb to the top of his or her airspace. Finally, ATC will hand the aircraft off to Center. No vectoring instructions are needed because the pilot has all of that information preprogrammed into their navigation system.
Looking at the narrative, we see that the instruction are even more specific than in the previous 2 examples. An aircraft departing 35L will climb on a heading of 354 to at least 1,100 feet and then fly heading 011 to the MECHL waypoint and so on. Since all of the heading information is provided from the time the aircraft leaves the ground, no vectoring instructions from ATC are required. The initial altitude of 10,000 is also given in the departure description. One important thing to note: If the tower controller issues a heading for the aircraft to fly after departure, then that overwrites the SID, and you'll have to issue vectors to the aircraft to have them rejoin the route.
Coming into the Terminal Area
When entering busier Terminal Areas, a STAR, or Standard Terminal Arrival Route can be used by the pilot to fly a predetermined route. This is essentially the reverse of a SID and acts as a funnel to bring aircraft from a general direction down to a series of specific waypoints. Reading a STAR is just like reading a SID and the information is presented in a very similar fashion and is designed to be easy to understand.
The following video will help get you acclimated to how a STAR works:
Letâ€™s look at a typical STAR for the Memphis International Airport:
We can see on this chart that it is for aircraft arriving into the Memphis Terminal Area from the west and southwest. The beginning points of the STAR are called transition as pilots are transitioning onto the STAR from the en-route portion of the flight. This STAR will bring the pilot from the transition all the way to within about 10 miles of the airport without any vectoring needed. Letâ€™s look at a single leg of the STAR:
On this leg of the STAR the pilot is expected to fly from the Texarkana VOR (TXK) to the FAYEE intersection. The chart tells us that this is done by flying the 071 radial. The altitude above the heading is the minimum en-route altitude (MEA) for this leg, meaning that it must be flown at or above FL220 (22,000 feet). The number below the heading is the distance of the leg in nautical miles. We also have some specific location as to the latitude and longitude of the waypoints, VOR frequency, etc.
STARs also contain published hold points. These are in place in the event that traffic gets backed up and aircraft need to be held somewhere until the traffic situation improves and aircraft can resume their flight plan into the Terminal Area. Published holds are identified by a line that looks kind of like a racetrack and circles back to the waypoint. In this case, there is a published hold at the JAMEA intersection. It is published as a hold to the south of the waypoint.
STARs also have points at which the pilot is expected to cross as a certain altitude. If the chart says â€œCross atâ€ a specific altitude, then the ATC should not have to give the crossing restriction to the pilot. If the chart says â€œExpect to cross atâ€ then the ATC will have to issue a descent to the pilot to cross the waypoint at a given altitude. For example:
On this STAR, the ATC will descend the aircraft to either 10,000 or 12,000 feet depending on which direction the airport is landing. The pilot will then have to descend at a rate that will allow them to be at this altitude when they reach the TAMMY intersection.
The chart also tells the pilot what to expect once they enter the terminal area:
Here, the departure description tells us that from the UJM VOR, if Memphis is landing south (18â€™s) the pilot will fly to the TWIKL intersection and then turn to heading 355 and expect a vector onto their final approach course. If the aircraft is a jet landing north (36â€™s), then they can expect the vector to be issued from the TAMMY intersection.
Area Navigation, or RNAV, is also used for STARs, just like it is for SIDs. The charts are very similar, except that like SIDs, the RNAV charts are usually more detailed and contain more specific fixes and navigation information.
The Tammy Three (TAMMY3) RNAV STAR is very similar to the UJM3 STAR and contains much of the same navigation information; however, a closer look shows us that after the TWIKL intersection, instead of a heading, there are additional fixes show that the pilot flies to. As with RNAV SIDs, there is also a more specific requirement for the equipment that must be on board for an aircraft to fly the STAR.
We also see the ATIS frequencies, and since this is an arrival chart, the approach control frequencies are provided as well.
Below is a legend courtesy of the FAA Instrument Handbook Chapter 8 which outlines the various types of items you may find on the graphical portion of a SID/STAR