Drupal CiviCRM Rules module: How to use the action "CiviCRM Mailing: Send email"?
The integration of CiviMail with the rules module is primarily for workflow purposes. i.e. they allow another person to approve a scheduled email. Thus a CiviMail has to be scheduled and approved before it can be sent out (if this has been enabled within CiviMail settings screens)

The action by itself does not create or schedule a CiviMail. It just approves it and/or sends it back to the creator (a link via email) for further edits and revisions.

This was work done in support of the New York State Senate's usage of CiviCRM an CiviMail