According to the European law, a General Declararion is a mandatory immigration document for flights leaving or entering the European Union and/or the countries of the Schengen Treaty. The information provided with a General Declaration allows for effective immigration and border control. The Dutch Border Police (Royal Netherlands Marechaussee) requires a notice in advance for such flights for General Aviation traffic (both inbound and outbound). This notice must be provided at least 2 hours prior to take-off by means of a submitted General Declaration (hereinafter referred to as GenDec).

The Schengen Treaty allows free travel of persons between the countries that signed the Treaty (which is a subset of countries of the European Union). However, there are some exceptions:

• United Kingdom and Ireland are part of the EU, but not part of the Schengen zone, hence a GenDec is required.
• Norway and Switzerland are not part of the EU, but are participating in the Schengen zone, so no GenDec is required.