Commercial Fixed Wing
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Communication Breakdown; Confusion
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Environment - Non Weather Related; Human Factors; Procedure
We got our IFR clearance from ZZZ Tower about 30 minutes prior to departure. We were surprised that ZZZ Tower closed shortly after getting our clearance; at XB:00 p.m. we taxied to the runway and made position announcements on the CTAF. After takeoff we contacted ZZZ Approach at about 1;500 feet AGL. Approach informed us that we should have gotten an IFR release from them on the ground.  We need to remember to get an IFR release for departure from Approach Control if the Tower closes after issuing our clearance.
In ZZZ; I called ZZZ Clearance and received our IFR clearance to ZZZ1 at approximately XA:30 p.m. local time. After a slight ramp delay; we pushed back around XB:10 p.m. The Tower at ZZZ closes at XB:00. We made all our CTAF calls and took off in clear VFR conditions. I checked in with departure at 1;400 feet. At that time Departure let us know we did not get our IFR release on the ground.I recommend once a Tower closes; even with a clearance received prior to closing; always contact Departure on the ground prior to departing and pick up your IFR release to destination. The cause was some confusion with already receiving the clearance and picking up the release after the Tower closed. Lesson learned is as described above; once Tower closes you need to pick up your clearance from Departure prior to taking off.
Air Carrier flight crew reported obtaining an IFR clearance before Tower closed; however; they departed after Tower closed and did not obtain an IFR release for departure.