Date: 202104
Local time of day: 1201-1800
Location: ZLC.ARTCC, UT
Aircraft: Military Transport
Operator: Military
Operating under: Part 91
Flight plan: IFR
Mission: Training
Flight phase: Cruise
Airspace: Class E ZLC
ATC / advisory: Center ZLC
Second aircraft: Military Transport
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Time Pressure; Situational Awareness; Confusion
Anomaly: ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport
Contributing factors: Airspace Structure; Human Factors; Manuals; Procedure
Primary problem: Airspace Structure

Narrative: Aircraft X and Aircraft Y were in IR302 which terminates inside MHRC SAA (Special Activity Airspace); not controlled by ZLC. Aircraft X called me and said he was requesting 110 at point C and entry into MHRC. He was level at 100 at the time inside a 108 MIA (Minimum IFR Altitude). I climbed the aircraft to 110; they were still in IR302 at this point. I called COWBOY (the controlling agency for MHRC) and asked if they were expecting Aircraft X; they said no they were not scheduled to be in MHRC today. I went back to the aircraft and told them COWBOY said they were not scheduled to be in there and could not enter the airspace. The pilot said okay and said they would talk to COWBOY. A few minutes later I called COWBOY and asked if they were talking to Aircraft X because he was turning north into their airspace. COWBOY said they talked to the pilot and told them they could not enter the airspace. I tried to contact Aircraft X to ask what they were doing and I could not get in touch with them.At that same time; Aircraft Y can on frequency and asked for the same climb and entry into MHRC. I told them standby and called COWBOY to ask about Aircraft Y and got the same answer. When I hung up the phone I saw that Aircraft X was turning eastbound into a higher MIA. I tried calling them again several times with no response. I asked Aircraft Y if he was in contact with Aircraft X; he said yes and I asked him to have Aircraft X return to my frequency. By the time he called me on the frequency he was back in the 108 MIA. I asked him to say intentions and he said he was talking to COWBOY. I asked him if he planned to orbit where he was until he got it figured out and he said yes. I climbed him to 130 since he would be going back into the higher terrain. I then asked Aircraft Y if they had the same plan and he said yes. I climbed him to 110 and then realized if he was orbiting he would also need 130 so I climbed Aircraft X to 140 and then climbed Aircraft Y to 130. A few minutes later; I realized that I hadn't radar identified either aircraft so I did that then. A short time later Aircraft X requested clearance back to ZZZ so I put them on a heading away from the airspace and issued the clearance. I then asked Aircraft Y if they wanted the same clearance; they did so I issued the clearance to them as well.I should have radar I.D'd both aircraft when they called me out of the IR route. Typically aircraft in IR302 don't call us for clearance into MHRC; they just follow the route into the airspace. I am glad they did call in this instance since they didn't have clearance into the airspace. Next time I will climb the aircraft to a higher altitude in case I lose radios since I didn't know exactly where he were going when he started to orbit. I should have asked for his backup plan.




Synopsis: Controller reported military aircraft flew below the Minimum IFR altitude after permission for special activity was denied.