Date: 201405
Local time of day: 1201-1800
Location: ZNY.ARTCC, NY
Aircraft: F/A 18 Hornet/Super Hornet
Operator: Military
Operating under: Part 91
Flight plan: IFR
Flight phase: Cruise
Airspace: Class A ZNY
ATC / advisory: Center ZNY
Second aircraft: B737 Undifferentiated or Other Model
Reporter organization: Government
Reporter function: Enroute; Instructor
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Training / Qualification
Second reporter function: Trainee; Enroute
Anomaly: ATC Issue All Types; Airspace Violation All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Separated Traffic
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: I was training a Developmental on Sector R55 at New York Center. I observed Aircraft X; at my boundary with Sector 25. Sector 25 was flashing a late hand off on Aircraft X to our sector at FL190 routed MXE direct LENDY. I instructed the RA at my sector to tell Sector 25 that we could not accept the handoff on Aircraft X due to head on traffic at that the same altitude. The trainee descended Aircraft Y; the head on traffic mentioned above; from FL190 to 170 to avoid Aircraft X. At this point; I took the frequency. I turned Aircraft Y and expedited his descent to maintain separation between Aircraft Y and Aircraft X. I then descended and turned Aircraft Z to maintain separation with Aircraft X. Aircraft X lost separation with both Aircraft Y and Aircraft Z. Aircraft X entered my airspace without approval and was in conflict with Aircraft Y and Aircraft Z. Aircraft X checked on to my frequency [a few minutes later].For the Controller trying to handoff the aircraft to follow all rules and regulations as per the 7110.65.


Second narrative: I was working Sector RA55 at New York Center. There was training at R55. Sector 25 requested control for descent on Aircraft Z; I approved descent and asked why descent was needed but Sector 25 ended the call without answering the question or giving his operating initials. Sector 25 asked if I knew about Aircraft X at nineteen and I said I did not. I observed Aircraft X; at my boundary with sector 25. Sector 25 was flashing a late handoff on Aircraft X to our sector at FL190 routed MXE direct LENDY. The R-side trainer told me to tell sector 25 that we could not accept the handoff on Aircraft X due to head on traffic at the same altitude. I told Sector 25 that Aircraft Y was going to the right. Aircraft Y was descended by the R-side trainee from FL190 to 170 to avoid Aircraft X. The R-side trainer turned Aircraft Y and expedited his descent to maintain separation between Aircraft Y and Aircraft X. He then descended and turned Aircraft Z to maintain separation with Aircraft X. Aircraft X lost separation with both Aircraft Y and Aircraft Z.Aircraft X entered my airspace without approval and was in conflict with Aircraft Y and Aircraft Z. At [a few minutes later] Aircraft X checked on to my frequency.For controller at adjacent sector to adhere to all rules and regulations as per the 7110.65


Synopsis: Reporters describe loss of separation between two aircraft due to a head on situation the Controller had previously denied; with a third aircraft.