The ELPAC test of English for Aeronautical Radiotelephony Communication was designed to assess the English language proficiency of air traffic controllers on the radiotelephony frequency. The aim of this project was to design and produce versions of the test that were suitable for pilots with a CPL. To this end, a needs analsysis was conducted to investigate who the communicative functions of pilots on the radiotelephony frequency differed to those of air traffic controllers. One of the test specifications made by EUROCONTROL, as the owner of the test, was that it needed to have the same look and feel as the ELPAC ATC test. Differences between the pilot and ATC formats exisit in the listening comprehension part of the test, for example. In the pilot test, test takers respond to transmissions from ATC, whereas in the ATC test they pay attention and are assessed on transmissions made by pilots.