In 2008 the International Civil Aviation Organisation (ICAO) implemented language proficiency requirements for air traffic controllers and pilots. To this end, ICAO introduced a rating scale with six levels of language proficiency. Level 4 is the so-called operational level that test takers need to demonstrate to keep their licence. The ELPAC test was designed by EUROCONTROL in Luxembourg to meet the ICAO language proficiency requirements. However, for a number of reasons the test originally only tested up to ICAO level 5. The aim of this project was to develop an add-on test for ELPAC that could be used in the assessment of ICAO level 6.