If you are in jail for Failure to Appear, it means a bench warrant was issued by a court because you had a court hearing and after three separate methods and attempts to summon you to court you were not located or you were served with the summons or subpoena and did not appear at the hearing. Irregardless of the hearing outcome, the court demanded your arrest. You came into contact with law enforcement afterwards and you were arrested due to the open bench warrant. When you appeared in court on the open bench warrant there was no court date because the date was set as upon apprehension. You are aware of the length of incarceration because it was explained.