Military
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 6
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Human Factors; Procedure; Airspace Structure; Chart Or Publication
I cleared the aircraft at pilots discretion to 5;000 feet. He was entering a 4;400 foot MIA (Minimum IFR Altitude); then a 3;200 ft MIA. Aircraft was cleared for approach and told to maintain at or above 3;200 feet until inbound at the Initial Approach Fix. Aircraft descended to 4;000 feet in 4;400 foot MIA. I need to re read approach clearance phraseology; I believe there was better phraseology available to clear the aircraft.
A Center Controller reported their use of improper approach clearance phraseology resulted in an aircraft descending below the Minimum IFR Altitude.