Date: 202005
Local time of day: 1801-2400
Location: ZLC.ARTCC, UT
Aircraft: PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Climb
Airspace: Class E ZLC
ATC / advisory: Center ZLC
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Developmental
Human factors: Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance
Contributing factors: Human Factors; Procedure; Airspace Structure
Primary problem: Airspace Structure

Narrative: I received a handoff on Aircraft X. I immediately recognized the aircraft was too low for my terrain. I pulled up my MIA (Minimum IFR Altitude) map; ran a route line; and verified the aircraft would need to be at 14;000 ft. to be above MIA. When Aircraft X checked on; I immediately asked the aircraft if they were capable of 14;000 ft.; or if they would prefer a vector to south to stay in lower MIA. The pilot of Aircraft X responded 'Yeah; 14;000 ft. is no problem!'. I told the aircraft to expect higher in 10 minutes; and the pilot of Aircraft X read back 'expecting 14;000 ft. in 10 minutes.' I had made the decision to climb the aircraft near a VOR which was about 3 to 4 minutes flying time from the higher MIA. I checked the aircraft climbing characteristics on ERIDS; which showed the aircraft was capable of 900 ft. per minute. As the aircraft would only need to climb 1;000 ft.; I felt comfortable giving the climb later which was roughly 10 minutes from his current position.I gave the instruction to climb to 14;000 ft. The pilot of Aircraft X read it back correctly. The plane did not climb immediately. It took much longer than I expected for the aircraft to begin climbing; especially given that the pilot was expecting a climb. Once the aircraft began climbing; I noticed the aircraft was only doing about 100 ft. per update. The aircraft went a few updates without climbing at all. At this point; the aircraft was within the 13;900 ft. terrain bubble. Knowing that the peak in that terrain bubble is near the center; I decided that as a safety measure I would turn the aircraft away from the center as he continued his climb. I gave the aircraft 10 degrees right; which the pilot followed. Once the aircraft showed level at 14;000 ft. and MSAW (Minimum Safe Altitude Warning) alert was done; I cleared the aircraft back on his route.I could have provided the pilot with an earlier climb. I held off giving the pilot an early climb due to the confidence in his answers. I didn't think climbing to 14;000 ft. would take as long as it did. If I gave a clearance to climb earlier; the issue wouldn't have occurred. The aircraft was on the south edge of a 13;900 ft. terrain bubble. If I would've given the aircraft present heading sooner or a 5 degree right turn; I could've avoided the 13;900 ft. bubble all together.




Synopsis: A Center trainee controller reported they waited too long to climb an aircraft to a higher altitude to stay above the Minimum IFR Altitude for its route.