Date: 201902
Local time of day: 1801-2400
Location: ZDC.ARTCC, VA
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZDC
ATC / advisory: Center ZDC
Second aircraft: Commercial Fixed Wing
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Situational Awareness
Anomaly: ATC Issue All Types; Airspace Violation All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I was working R50 with low traffic volume. I had just switched Aircraft X at FL360 to Dixon (09) and realized there was a significant overtake with Aircraft Y also at FL360. I quick looked Sector 34 which was combined with Sector 35 and saw that FL340 would be available for Aircraft X. 34/35 were combined at 34 next to me so I leaned over to the 34/35 controller to make sure FL340 would work for them in both of their sectors for Aircraft X. They said that FL340 would work. I called R09 and told him I had just noticed the overtake with Aircraft Y that was flashing to 09 and that FL340 was available for Aircraft X if they would flash the aircraft to 34 since they had track control and comms of Aircraft X. Shortly after; I was getting bumped for training purposes at my sector and during the position relief briefing I noticed that Aircraft X; that was still in my airspace was now climbing to FL400. I had not given control for this. Aircraft X and Aircraft Y were both routed over ISO J121. I had numerous other aircraft south of CVI also going to ISO J121. There was Aircraft Z at FL380; Aircraft A Heavy fast and at FL400 behind the Aircraft X. There was also Aircraft B cutting across all of these aircraft at FL430 direct ZZZ. I knew that the new overtake with Aircraft A Heavy would not be imminent so I gave the sector to the new radar team and went to relieve Sector 09 who was next up for a break. I went over and asked what the plan was with the Aircraft X since there was now a new overtake at that altitude. The controller at 09 said that they didn't see the Aircraft A because it wasn't on the flash yet and they assumed I just didn't think of taking the aircraft to FL400 even though I said FL340 would solve the problem. The 09 controller didn't even quick look my sector (which still wouldn't prevent the violation) or scan for limited data blocks before changing Aircraft X's altitude in my airspace by 4000 feet. They offered no solution to the problem now at hand and said that now I could figure it out since I would be working the airspace. Before I took the sector I scanned the ACL (Aircraft List) and scope for northbound traffic at FL410; found none; and told the controller to climb Aircraft A to FL410 IAFDOF (Inappropriate Altitude For Direction Of Flight) before they left so that I would at least have altitude separation when taking the sector. Luckily there was no northbound traffic at FL410 and ZJX approved the IAFDOF since they would outrun the slower traffic now at FL400. If I had noticed the original overtake prior to issuing a frequency change of Aircraft X this all would have been avoided. However; overtakes can easily be missed and the R09 controller should have handed Aircraft X to Sector 34 for lower since I had already told them that solution would work. If they wanted to try something else; they absolutely needed to request control prior to assuming I hadn't thought of other options and then felt they had the right to violate my airspace especially without doing a full traffic search. This situation could have cause much more dangerous problems but luckily it didn't. However; this cannot be a habit that is allowed to form amongst controllers.




Synopsis: Washington Center Controller reported an unsafe situation due to lack of correct coordination with another sector.