Helicopter
Air Traffic Control Fully Certified
Confusion
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance
Human Factors; Procedure
TRACON lost all RADAR and declared ATC ZERO. I was called to the Sector to be the D-Side. I called ZZZ1 TRACON for an airspace briefing and we took all of their traffic and airspace. The helicopter checked in requesting an ILS approach into ZZZ. The R-Side vectored him for the approach and cleared him in. Shortly after; we were notified by the Supervisor that a Challenger had been cleared out of ZZZ; IFR. No separation was provided between the two aircraft. The helicopter was still on frequency; so he was issued a clearance to climb and turn in hopes of avoiding the departing aircraft. The helicopter cancelled IFR. There were several causes of this event. First; both the R-Side and I were unaware that there was a VFR Tower at ZZZ airport. We did not know we had to APREQ inbounds. Second; I don't know who approved the clearance for the Challenger; the ZZZ1 Approach Controller did not say anything about it to me during the briefing; so when my Supervisor came over and told me that he had been cleared off; that was the first I had heard of it. There was a lot of confusion due to the transfer of airspace. Normally; when we work ZZZ1 airspace on the midnight shift; the Towers at ZZZ1 and ZZZ are closed. We did not have communications in place for ZZZ Tower. Also; I have basically no experience transferring airspace from a facility that has gone ATC zero. They were unable to initiate automated handoffs; so I basically had to 'wing it' and have the ZZZ1 Controller transfer communications for all aircraft he was working; so that we could RADAR identify them. Also; according to the LOA with ZZZ1 TRACON; if they do lose RADAR; they are supposed to continue working aircraft NON-RADAR below 070. For some reason; we took the whole airspace. I am unclear about how the Challenger received a clearance to depart ZZZ; so I cannot comment about that. I think that lack of training in transitioning from a loss of RADAR capability is the largest contributing factor that I can identify in this scenario. We have periodic training in the simulator that is intended to cover less common events such as this. A scenario like this should be added to that training. Also; had LOA procedures been followed; confusion about communication and procedures with ZZZ and ZZZ1 Towers would not have been a factor.
Enroute Controller described a loss of separation event when an adjacent TRACON lost RADAR; declared ATC ZERO; and resulted in an IFR arrival and IFR departure not being separated. The reporter suggested additional training on unusual events.