Date: 201910
Local time of day: 1201-1800
Location: ZTL.ARTCC, GA
Flight conditions: Marginal
Weather elements / visibility: Thunderstorm
Aircraft: EMB-505 / Phenom 300
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E ZTL
ATC / advisory: Center ZTL
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Workload; Communication Breakdown; Distraction; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Detector: Automation Air Traffic Control
When detected: In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Weather; Procedure; Human Factors; Environment - Non Weather Related; Airspace Structure
Primary problem: Weather

Narrative: When I sat down at the sector; all arrivals to the airport were in holding because our specific arrival gate had been shut off due to thunderstorms moving through the area. Most of the aircraft in holding had been holding for a while. Most of them were getting close to their EFC (expect further clearance) so they were asking for new EFC times. Also weather was moving over that particular holding fix and most of the aircraft were asking to move to a different holding fix and some even decided to divert to a different airport. Because of the increased work load and because several aircraft were requiring my attention at the same time; I didn't realize I had a low altitude aircraft that was about to fly into an area of higher terrain. Just before I took the sector; the d-side (radar assist) had accepted the handoff on an aircraft that was inbound to a satellite airport. The previous sector had coordinated with my d-side that the aircraft was deviating and descending to 3;700 ft. The pilot had indicated to the previous Controller that they were intending to descend to the lowest altitude possible to try and get the airport in sight. If they were unable to see the airport; they were planning to fly an instrument approach. Because of weather in the area; the aircraft had deviated about 30 miles east of the airport he was supposed to be landing at. So much so that they were now in approach control's airspace. When I sat down at the sector; the pilot stated they wanted to go ahead and request an instrument approach. I was unaware of the coordination between the d-side and the previous sector so I told the aircraft to stand by. I was expecting my d-side to request control of the aircraft from approach so I could turn the aircraft toward an initial approach fix. I didn't know it at the time but approach had already released control of the aircraft to the previous sector but the d-side didn't pass any of this information along to me. It didn't really matter that much anyway because I was being distracted by several other aircraft so I was unable to look up the approach information for the airport. After a couple of minutes; the aircraft again requested an instrument approach. I looked up the approach information and cleared the aircraft to an initial approach fix. At this time I realized the aircraft was about to fly into an area with an MIA (minimum IFR altitude) of 4;800 ft. I told the aircraft to climb to 4;800 ft. for the higher MIA. Up until this point the terrain alert never indicated the aircraft was entering an area of higher terrain because the aircraft was close enough to the destination airport that the terrain alerts were automatically suppressed. Once I saw the aircraft had reached 4;800 ft. I cleared it for an RNAV approach and then turned my attention back to the other aircraft in the sector.A few minutes later; the terrain alert started flashing for the aircraft on the RNAV approach. I looked over to see the aircraft about to fly into an even higher MIA area of 6;400 ft. I didn't think much about it at the moment because the aircraft was on an instrument approach and its normal to be below a sector MIA as long as the aircraft is at or above the altitude prescribed in the approach procedure. It took me a few minutes to realize what I had done but basically I had initially climbed the aircraft to 4;800 ft. for the first higher area of terrain and cleared them for the approach. The initial segments of the approach though were at 6;400 ft. so essentially cleared the aircraft for an approach below the altitude prescribed by the approach. By the time I realized what I had done; the aircraft was on the final segment of the approach and at the altitudes prescribed by the approach.I think I would have really benefited from better coordination from the d-side. After I saw the aircraft about to fly into the 4;800 MIA area I asked the d-side if they had accepted the handoff from approach at that altitude. I was basically told that they had just accepted the handoff and didn't know anything else about the aircraft. It was only afterwards when I watched a recording of the session that I found that the d-side had been made aware of exactly what the aircraft had been doing. Regardless of the lack of communication though; I am fully responsible for my actions and mistakes. I should have paid more attention when I saw an aircraft entering my sector at an unusually low altitude. I was rushing to try and keep up with the sector and missed a critical piece of information. In hindsight; I don't think there was anything else going on in the sector that was more critical than making sure an aircraft stays above terrain. I will be working harder in the future to make sure I keep my priorities in order.




Synopsis: ZTL Controller reported they vectored an aircraft below the Minimum IFR Altitude.