TBS policy states that you should only pursue termination on probation if four criteria are met:
https://www.tbs-sct.gc.ca/pol/doc-eng.aspx?id=22379
The employee on probation knows the specific job duties and requirements of the position;
The employee on probation is aware of the required standard(s) of performance and appropriate conduct:;
The employee on probation receives feedback when performance or conduct requires improvement; and
The employee on probation receives the appropriate training for the position.
The policy also instructs managers and supervisors to ensure they are acting in good faith, which I interpret as meaning either of three things must be true:
This means that you have a couple of grounds of appeal, in the event that you object to the termination:
But that's about it.