While the detention is ongoing, the appeal under § 22a BFA-VG can be brought at any time, ideally combined with an application for a less restrictive measure.
As long as the immigration detention continues, the detention appeal under § 22a BFA-VG can be brought at any time, that is, without being bound by the six-week period. The Federal Administrative Court decides in an urgent procedure, where the person is still held as a rule within one week and usually after an oral hearing. Combine the appeal with a concretely reasoned application for a less restrictive measure under § 77 FPG.