Class 1 - Explosives, articles and substances are assigned to one of six divisions and to one of thirteen compatibility groups. Not all compatibility groups are to be found in all divisions.
Only explosives in Division 1.4, compatibility
group S are permitted on passenger aircraft.
Only explosives in Division 1.3, compatibility
groups C and G and Division 1.4, compatibility groups B, C, D, E, G and S are permitted on a cargo aircraft. (Approvals or Exemptions are often necessary).
Example:
1.4 S (RXS) articles and substances that present only a small hazard in the event of ignition or initiation during transport (cartridges for weapons).