Codes use the digits 0 to 7 only. Never issued: 7500 (unlawful interference), 7600 (radio failure), 7700 (emergency), 7000, 2000, 1200 and 1000 (conspicuity and VFR codes), 0000 and 7777. Codes already issued this session are not repeated.
For flight simulation only. Always follow your aircraft's procedures and the published charts.