I think you may have looked at table A2.3 for crew positions. Table A2.2 reads as follows:
Authorized Mission Symbols (Note: Only mission symbols listed in this table are valid. In ARMS the mission symbol is a five-character field. The first two characters must be IAW this table. MAJCOMs may assign additional characters as required (see Notes 1 and 2 at end of table).
CA, CC, Air Rescue CF Coded Aircraft Missions, and TF Coded Aircraft Missions as applicable
A1 Scheduled Flights. Missions where the main goal is to move cargo or passengers on a scheduled frequency.