Aerodrome Twilight Table Data

The 'Aerodrome Twilight Table Data' option provides IFIS users with access to tabulated twilight data for one or more selected aerodromes.

Twilight data consists of two values for each date and location:

1. MCT - The official beginning of Morning Civil Twilight (the beginning of daylight).
2. ECT - The official end of Evening Civil Twilight (the end of daylight).

All twilight times are given in Coordinated Universal Time (UTC).

New Zealand Standard Time (NZST) is 12 hours ahead of UTC. New Zealand Daylight Time (NZDT), which is 13 hours ahead of UTC, commences at 0200 (NZST) on the last Sunday in September and ceases at 0300 (NZDT) on the first Sunday in April.

Selection of locations

There are three methods for inputting the identities of the aerodromes for which you would like Twilight data:

1. Type the four-letter ICAO location indicators directly into the 'Locations' input box. If you are specifying more than one aerodrome, please insert a space between location indicators, e.g.
   NZWN NZCH NZDN
2. Click on an aerodrome location indicator on the displayed map. This will insert the location indicator into the Locations input box. If an aerodrome is already listed in the input box, clicking on the corresponding location indicator on the map will remove the aerodrome from the input box.
3. Select the aerodromes from the drop-down list. The list displays ICAO aerodrome codes and the aerodrome name (in brackets) in a north to south order. The list only includes aerodromes for which twilight data are available from Airways. Click on an aerodrome in the drop-down list and its location indicator will be inserted into the Locations input box.