Howto:Fly a circuit pattern

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A circuit pattern (also: airfield traffic pattern or just pattern) is a standardized procedure to regulate the air traffic around an airport, which guarantees a safe and smooth processing of the departing and arriving traffic and also minimises the noise pollution of populated areas around the airport.

This tutorial explains how to fly a pattern in FlightGear using the example of Siegerland Airport (EDGS) , a medium-sized airport in the middle of Germany and you will fly the Cessna 172P, the default aircraft for FlightGear and a very nice training aircraft.

Basics of a circuit pattern

Sections

So what do you need to know in order to fly a pattern properly? Basically a pattern is a rectangle with the runway on one of the long sides and you follow the flight path by turning left 90 degrees four times.
The individual sections of the pattern are called:

1. Upwind/Departure: The first section after takeoff where you maintain runway heading and start climbing to the pattern altitude.
2. Crosswind: After a lift turn by 90° you fly the crosswind leg perpendicular to the runway heading while you reach pattern altitude.
3. Downwind: A long leg parallel to the runway where you fly level at pattern altitude. During the gliding training the trainee pilot will fly various maneuvers in this leg. When you are abeam the runway threshold you should start preparing the approach.
4. Base: The second but last section perpendicular to the runway where you fly right up to the extended centerline of the landing unwy.
5. Final: In the final approach you start a continuous descent above the extended centerline until touchdown. If necessary, you can do a go-around after touchdown and fly a second pattern.

Altitude

It's very important to know the elevation of your airfield in order to know at which altitude you have to fly the pattern. The elevation of Siegerland is 1965 ft MSL, or roughly 2000 ft (to make it easier). The pattern altitude is usually about 1000 ft AGL, so in this case you have to fly at 3000ft MSL.

Headings

Which headings do you have to fly? Departure and final have of course the same heading (runway heading), ca. 130°. Crosswind has 90° less, so you have to fly at 40°. On downwind you have to fly directly the opposite direction to your runway, therefore you nedd to fly 310°. And finally, base has a heading of 220°.

Startup preparations

You need to start FlightGear with the following options:

Integrated launcher

Note  For more information about the new Qt5 launcher see it's wiki page

• "Aircraft"-tab: Select the Cessna 172P Skyhawk (1981 model, detailed)
• "Settings"-tab: Select Noon in the dropdown menu "Time of day". If you want, choose Enable Multi-sample anti-aliasing. Important: Choose the option Enable automatic scenery downloading (TerraSync). Uncheck the option Fetch real weather online. If desired, choose Start full-screen. In the text box under Additional options add the following:

  --lon=8.077177
  --lat=50.707672
  --heading=70

• Click Run!

FGRun

Note  For more information about the extensive and complex, but old launcher see it's wiki page

• Aircraft selection page: Select the Cessna 172P Skyhawk (1981 model, detailed) from the list. Then click Next.
• Airport selection page: You dont' need to specifiy an airport, so you can skip this and click Next.
• Options page: Choose the option Time of day and set it to Noon. Uncheck the option Real weather fetch. Choose the option TerraSync. On the bottom right, click Advanced...
• Advanced options:
  • General: Make sure that the lines TerraSync directory and FG_SCENERY contain the same path (you can change the path FG_SCENERY on the first page).
  • Initial position: Type in Longitude: 8.077177. Type in Latitude: 50.707672. Type in Heading: 70.
  • Change the other options in this dialog window only if you really know what you're doing!
  • Click OK.
• Click Run!

Command line

Note  For more information about the command line and it's capabilities, see it's wiki page

Windows

• Press Start+R.
• Enter the path to the FlightGear program in quotation marks (by default this should be "C:\Program Files\FlightGear\bin\fgfs.exe")
• Behind that, type:

  --fg-scenery=PATH\TO\YOUR\SCENERY\FOLDER --terrasync-dir=PATH\TO\YOUR\DOWNLOAD\LOCATION --aircraft=c172p --lon=8.077177 --lat=50.707672 --heading=70 --timeofday=noon --enable-terrasync --disable-real-weather-fetch

  Important: The paths to --fg-scenery and terrasync-dir should be identical! If you didn't mess anything up, the default is C:\Users\{USERNAME}\Documents\FlightGear\TerraSync
• Press ↵ Enter or click OK!

Linux

• Open a terminal window.
• Type

  fgfs --fg-scenery=PATH\TO\YOUR\SCENERY\FOLDER --terrasync-dir=PATH\TO\YOUR\DOWNLOAD\LOCATION --aircraft=c172p --lon=8.077177 --lat=50.707672 --heading=70 --timeofday=noon --enable-terrasync --disable-real-weather-fetch

  Important: The paths to --fg-scenery and terrasync-dir should be identical! If you didn't mess anything up, the default is /home/{USERNAME}/.fgfs/TerraSync
• Press ↵ Enter!