Definitions of operational:

• adjective:   of or intended for or involved in military operations
• adjective:   pertaining to a process or series of actions for achieving a result

  Example: "Operational difficulties"

• adjective:   being in effect or operation

  Example: "De facto apartheid is still operational even in the `new' African nations- Leslie Marmon Silko"

• adjective:   fit or ready for use or service

  Example: "An operational aircraft"