Date: 202101
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Aircraft: Fighter
Operator: Military
Operating under: Part 91
Flight plan: IFR
Mission: Training
Flight phase: Descent
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Confusion; Situational Awareness; Time Pressure; Troubleshooting; Human-Machine Interface
Anomaly: ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
Result: Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Procedure; Airspace Structure
Primary problem: Airspace Structure

Narrative: There was a recent change with how our the Military Operating Area (MOA) has been handled in conjunction with ZZZ1. For the years past the MOA has been handled as an autonomous airspace which Center cleared [aircraft] in and out of. The decision has been made to have the ZZZ1 control the aircraft in and out of this airspace by designating a new control area. This week was the first time [new control area] has been in operation since its development and we expected issues; and encountered numerous airspace violations and automation issues throughout the day. The event I am reporting was only one of the numerous issues I encountered during this 1.5 hour session; and there will be numerous reports regarding this airspace from other controllers.The situation that caused the most alarm was [Aircraft X; Aircraft Y] which is a flight of 2. We received a call from [new control area] giving us the 5 minute notice that [Aircraft X; Aircraft Y] is ready to leave the airspace. This is the procedure that is published in the Letter of Agreement and following this call [new control area] will initiate an automated radar hand-off. For [Aircraft X; Aircraft Y]; there was no hand-off initiated and [Aircraft X; Aircraft Y] called Center stating they were at 25;000 ft. descending to 13;000 ft. I look in the airspace and search the 5 limited targets and do not see [Aircraft X; Aircraft Y]'s beacon code. I then notice a beacon code 5 to 10 miles outside the airspace at 25;000 ft. which is heading back to ZZZ1 and towards some ZZZ arrivals. I quickly pair the data blocks and establish communication with [Aircraft X; Aircraft Y]. Thankfully this time the traffic into ZZZ was far enough away that this was not an immediate issue. This area [Aircraft X; Aircraft Y] was in is a very heavy area for military traffic; ZZZ arrivals; ZZZ Departures; ZZZZ1 Arrivals; ZZZZ2 Departures; and ZZZZ3 Departures. If this issue happens again during a busier session this could very well end in a TCAS/RA event or even worse due to the speed of the exiting [aircraft] speeds. Either better training on the procedures for the ZZZ1 Controllers and the [aircraft] fighter squadron; or amendments to the [new control area] procedures.




Synopsis: A Center Controller reported a flight of two military aircraft exited a Military Operating Area and began descending from 25000 feet without communications or a radar handoff from the military controlling agency. The reporter states there is a new military controlling facility and procedures which have been violated many times since the new procedures were implemented.