Light Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 10
Communication Breakdown; Situational Awareness; Time Pressure
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Airspace Structure; Human Factors; Procedure
ZZZ Tower called for a release on Aircraft X; with visual separation with previous arrival. The [agreement] with ZZZ requires they climb the Departures to 14;000 feet. The field elevation at ZZZ is XXXX feet. I missed the aircraft checking at [923 feet above field elevation]; because that is so far out of the expected. Our MIA (Minimum IFR Altitude) at the field is 6;000 feet. I assume this was a readback error between Tower and the pilot. Tower was hustling to get the departure off before the arrival landed. It was starting to raise an alarm in my mind right before the pilot requested higher. I should of caught it when the pilot checked on. The Mode C hit of 4;100 feet reinforced my expectations that they would be climbing to 14;000 feet.
Center Controller reported a departure which was supposed to be assigned 14;000 feet checked on their frequency level at 4;000 feet so the aircraft flew below the Minimum IFR Altitude.