Navigation - Lesson One
- .Around airports: SIDs and STARs. -

About SIDs and STARs:

When flying in or out of busy airports, pilots use what are called Standard Instrument Departures (SIDs) and Standard Terminal Arrival Routes (STARs). These procedures are used because it would be extremely difficult for an Air Traffic Controller to give radar vectors to every pilot within the crowded airspace around a busy airport. By using SIDs and STARs both the pilot and the controller knows where the aircraft should be throughout the procedure. This means less workload for pilot and controller, so the controller can concentrate on maintaining separation between multiple aircraft and the pilot can concentrate on flying. Communication between pilot and controller is no less important, however. Remember: the instructions of the controller have precedence over the described procedure.

In case of a communication failure, it is vital that the pilot be aware of his Clearance Limit. If neither the controller nor the SID/STAR chart specifies otherwise, the Clearance Limit for flying SIDs and STARs is the last waypoint of the procedure followed. When you reach your Clearance Limit and have no further clearance from the ATC you cannot continue your flight, but you must hold until further instruction.

Flying SIDs and STARs requires a careful study of the relevant charts before departure, so that the pilot has got a general comprehension of the procedures. It's too late to search for waypoints when the aircraft is airborne. For well prepared pilots, however, SIDs and STARs are not so difficult to fly, especially if they have entered the SID/STAR routeing into the FMC included in FS Navigator.

A SID or STAR consists of a title, a brief description of the procedure to be followed, a main diagram (vertical projection of the flight path), and sometimes a profile view of the flight path. Click here for an example.

Standard Instrument Departures (SIDs):

A SID is a predetermined route which giudes the aircraft from the departing runway to the first waypoint on its flight plan. From this waypoint the aircraft flies its planned route. As each airport has got at least two runways you can depart from there are usually several SID routeings to each waypoint depending on the active runway. In addition, there may be different SIDs for different aircraft types.

E.G. one of the main waypoints in the Dublin area is LIFFY intersection. There are 8 SIDs out of Dublin Airport that takes you to LIFFY. These eight SIDs consist of two routes from each of the main runways (10, 28, 16, 34) - one route for Category ‘C’ and ‘D’ aircraft, and one route for Category ‘A’ and ‘B’ aircraft. Aircraft categories are specified in the Operations Manuals.

The main diagram shows the flight path to be followed. The most important items on the diagram are:

• Waypoints (defined by Navaids, Headings and Distances) - must be followed precisely
• Altitude and Speed Restrictions - must be observed except when ATC instructs otherwise

Standard Terminal Arrival Routes (STARs):

A STAR is a predetermined route that takes the aircraft from the last waypoint of its flight plan to the starting point of the approach, called Initial Approach Fix (IAF). Since STARs don't take the aircraft down to the runway, a single STAR may "feed" several approaches with the same IAF. For this reason, airports usually have only a few STARs for arrivals from the North, South, East and West.

As with SIDs, the main diagram shows the flight path to be followed. The most important items are:

• Waypoints (defined by Navaids, Headings and Distances) - must be followed precisely
• Holdings (most STARs contain one or more holdings) - must be executed on ATC request
• Altitude and Speed Restrictions - must be observed except when ATC instructs otherwise

Example Flight: Dublin - Heathrow using SIDs and STARs in ATC environment

• Position your aircraft on Dublin apron, run SquawkBox and connect to SATCO/IVAO.
• Get the local weather report for EIDW by switching to the Dublin ATIS frequency.
• Request a weather forecast for EGLL from your controller, probably Dublin Ground.
• Send your flight plan. If you are familiar with SIDs & STARs you should include them in your FP.
• Contact Dublin Ground and request clearance to your destination, in this case London Heathrow.
• Your clearance will sound something like:
  “Emerald 737, you are cleared to London as filed via LIFFY 2A departure, Squawk 3201”
  The above clearance instructs us to fly a LIFFY 2A departure. This is the SID that will take us to the LIFFY intersection where we'll join the airway to follow. The SID routeing says to climb straight ahead from RWY 28 until reaching the OE beacon, then make a right turn to intercept the 279 radial from the DUB VOR. After crossing the VOR continue along the 099 radial to the LIFFY intersection.
• Taxi to RWY 28, take off, and follow the SID, climbing initially to 5000ft then to FL310 as cleared.
• After reaching the LIFFY intersection, route direct to the WAL VOR then to the HON VOR.
  This is the first waypoint of the Bovingdon 1A STAR used by aircraft arriving from the Northwest on airway UB3. This STAR involves flying to the WCO NDB then to the BNN VOR. We are to cross BNN at FL070, so I would recommend starting the descent about 70 miles from the BNN VOR.
• Fly the STAR as far as BNN descending to FL070 or as instructed.
• Before reaching the BNN VOR we will be handed off to Heathrow Approach who will give us radar vectors to the point when the ILS approach can be commenced, then clear us for the approach.
• The clearance will sound something like:
  "Emerald 737, you are cleared for the ILS approach to runway 27 right, report established"
• Once we have the clearance, we should continue as per the approach chart, intercept the localizer, then descend with the glide slope and land (provided we have a landing clearance from Heathrow Tower).
• Taxi to the terminal and shutdown.

Now, you know the principles of flying in and out of busy airports using real-world procedures. When you fly in ATC environment, controllers will assume that you have got the charts for your home as well as your destination airport and give you a clearance involving SIDs and STARs. In order to make them happy, you should obtain the relevant charts whenever possible and be prepared to fly the described procedures. You can find links to various SID/STAR download sites un the EMD HUBS pages. In case you cannot obtain the required charts, you should advise virtual controllers by typing the words "NO MAPS ON BOARD" in Squawkbox' comments box.