Date: 202101
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: Mixed
Light: Daylight
Aircraft: Light Transport; Low Wing; 2 Turbojet Eng
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Multiengine
Human factors: Time Pressure; Troubleshooting; Workload; Communication Breakdown; Confusion; Distraction; Situational Awareness
Second reporter function: Captain; Pilot Flying
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Airspace Structure; Environment - Non Weather Related; Human Factors; ATC Equipment / Nav Facility / Buildings
Primary problem: Environment - Non Weather Related

Narrative: The events described here are recalled to the best of our ability.  The situation was very dynamic; and communication was often difficult.  On date; on a flight initially planned from ZZZ to ZZZ1 we were flying in a type X aircraft between FL360 and FL400.  Everything was proceeding normally until a reroute that would have taken us to toward the west side of State Y and State X; then to ZZZ2 on the east side of State X; then back to ZZZ1 in central State X.  This is unusual; but we assumed it was due to weather in central State X.  We also thought there was a good chance the route would be changed; so we were not overly concerned.  As we were approaching the southern limit of ZZZ Center's airspace; we received another relatively complex re-route taking us to ZZZ3 then northeast back to ZZZ1.  At approximately that time we started hearing reports about airports in north and central State X being closed.  While we could see some weather on NEXRAD radar; it did not seem to be severe enough to close so many airports.  However we had received no other explanation for the situation.  After evaluating the new routing and analyzing the situation with the closed airports we determined it would be unwise to continue on that route to ZZZ1.  We initially requested and received clearance to change the destination to ZZZ4.   Also; at about that time we received instructions to contact ZZZ1 Center at a point some distance ahead (however the exact location is now forgotten).As we programed in the new destination and continued to hear reports of all or most airports in central and north State X now closed; (most likely not actually closed but unavailable in a non-radar environment already overloaded with traffic) we determined we were approaching minimum fuel and continuing on into an unknown situation would be unwise.  We then requested a diversion to ZZZ5 and declared minimum fuel.   We were told ZZZ5 was also closed.  Our minimum fuel status was never acknowledged; even though we stated 'minimum fuel' twice.  At about this time we were told to hold at ZZZZZ waypoint.  We were not given an EFC time and as we started the hold; we lost contact with ZZZ Center.  At this point we were on the verge of declaring an emergency; but an airline flight began relaying messages between us and ZZZ Center.  We stated we wished to divert to ZZZ6 and were told that was approved but we needed to do so VFR; even though we were at FL270.  Shortly thereafter we were told to contact ZZZ Approach even though we were still in the flight levels.  Since we were basically over ZZZ6 we did a rapid descent and contacted approach while doing so.  Eventually we were vectored for an approach and landed at ZZZ6.It should be noted that we were never informed that we were no longer in radar coverage; or that we would lose communication with ZZZ center before establishing contact with ZZZ1 Center.  We were also never informed that ZZZ2 Center had gone to ATC Zero.  We had also been cleared to lower altitudes; significantly increasing our fuel burn. We later learned during a phone call with ZZZ Center that ATC kept the ZZZ2 Center airspace open even though the center had gone ATC Zero.  The methodology FAA Air Traffic Control Centers are using to deal with COVID related ATC Zero situations is extremely confusing and dangerous; especially when attempting to route traffic through a non-radar environment. It requires the use of complex routes that include waypoint names that are difficult and time consuming to say and spell.  Had we been informed that ZZZ2 Center was ATC Zero we would have diverted before ever reaching ZZZ2 Center airspace; added fuel and waited for the center to re-open.  Had we been informed of the lower altitudes we would be required to fly or of the extended routes required we would also have made other plans.As it was; we remained in a reactionary mode for much of the flight.  We were unaware of the situation with ZZZ2 Center until after landing.  While we never failed to comply with an ATC clearance; we were apparently still expected by ZZZ1 Center in spite of being cleared by ZZZ (as best we can tell) to divert to ZZZ6.We have the highest respect for air traffic controllers.  But on date the ATC system itself severely failed.  In addition to the primary events of this particular report; at various times during today's flights numerous other ATC irregularities (to be generous) occurred.  For example; after receiving an IFR clearance on the ground at ZZZ6 we were cleared for a VFR takeoff and told to contact Approach in the air; that they were expecting us.  Upon contacting approach; who did not seem to be expecting us; they instructed us to climb to 3;000 feet.  We were then just left there; in some strange limbo state; not knowing if we were VFR or IFR; at night; at 3;000 feet; in a jet at 250 knots.  After prodding approach; we eventually received our IFR clearance; the same one we were given before takeoff.  We have no explanation for this.Furthermore; when arriving at ZZZ4 we; and several other aircraft; were instructed to hold as published at ZZZZZ1 Intersection while we were stacked up for the RNAV Runway X approach.  However; there is no published hold on the RNAV Runway X approach at ZZZZZ1.  There is a hold in the same physical location on the ILS X approach; but the name of the fix is ZZZZZ2; not ZZZZZ1.It was not a good day for us or ATC.


Second narrative: Our flight began and proceeded normally. Clearance was issued without any indication of flow problems in route. However; approximately halfway into the flight; reroutes were issued encompassing routing to ZZZ7 and ZZZ3. Multiple changes ensued and it is difficult to recall them all at this point. We surmised that we were operating as in a non-radar environment. However; we were never told that was the case. We complied with instructions. In the process of calculating and verifying routing and ETA's; additional instructions were given. Bear in mind some of this rerouting required headings; in some cases; 120 degrees off course. Additionally; we also had 120 plus knot headwind. Both of these factors combined were a bit unusual and prompted me to apply additional focus on to verify ETA's. We were ultimately informed that we would not be able to land at our destination; ZZZ1. Other requested nearby alternates were denied. We requested reroute to our next filed destination; ZZZ4. However; upon quickly re-calculating our fuel we determined we could not safely make that destination.At one point we were instructed to hold at ZZZZZ waypoint. We complied with instructions and held at ZZZZZ. In the hold we requested landing at ZZZ5 and were informed it was closed as well. At this point I remember discussing the possibility of declaring an emergency and landing before getting into a fuel critical situation. We were very close to ZZZ6 and requested landing there. Near this time; we realized that ATC did not hear us. Another airline flight crew relayed a VFR clearance from ATC to descend from FL270 to ZZZ6. In close proximity to ZZZ6; I initiated a relatively rapid descent approximately 4;000 FPM. Upon establishing communication with the local controllers at ZZZ6; the flight proceeded more or less normally until landing.On the ground at ZZZ6 we were informed that ATC would be back to normal at XAX0Z. We took on extra fuel as a precaution; filed and took off for ZZZ4. Upon receiving clearance to ZZZ4; ZZZZ6 Tower gave us the unusual clearance of proceeding VFR with the assurance that ATC was 'expecting' us. We took off VFR originally cleared to 2;100 feet. We continued to prompt for higher altitude and were cleared to 3;000 feet. For the initial part of the flight we were in limbo regarding when we would receive an IFR clearance. We were also relayed a phone number for ZZZ Center and instructed to call them when we landed in ZZZ4.Due to all the confusion and delays we arrived at ZZZ4 later than normal for us. We arrived at the time the tower was closing with multiple airplanes landing ZZZ4. We received; what seemed to me; a rather nebulous holding instruction for a fix a bit hard to identify given approach outages at ZZZ4. However; it was manageable and after descending in sequence through the holding pattern we landed safely at ZZZ4. I do not know if this situation is normal at the time of cessation of Tower operation at ZZZ4; however; it was very cumbersome. Upon landing at ZZZ4; we contacted ZZZ Center as instructed. It was a cordial conversation on both sides attempting to fully understand what had occurred. I realize COVID-19 has been a challenge to us all; however I would strongly suggest a different approach to the ATC Zero situation we have now. Such a distraction of multiple clearances with little time to verify and stabilize orientation before another one is issued; coupled with calculations for diverting; and lack of communication is a challenge and potentially dangerous for one aircraft. When that is multiplied by tens of aircraft; it seems to me that has to be detrimental to safety.  I was as close to declaring an emergency as I have ever been. Again; I realize COVID has been a challenge to us all. I also realize yesterday was an equally frustrating challenge for ATC personnel; and it is certainly not my intention to impugn them in any way.  If I can further help or facilitate a better solution for pilots and ATC; I would be more than happy to help. I hope this account from a pilot perspective is useful.


Synopsis: Corporate flight crew reported communication issues with ATC resulting in a minimum fuel situation due to a Center going ATC Zero.