Date: 202012
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent; Climb; Taxi
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Workload; Time Pressure; Situational Awareness; Fatigue; Distraction
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate; In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: I wanted to take a few minutes to relate to you my personal experiences during the events that transpired.  We were at the tail end of a lengthy four day trip; with the usual holiday related challenges; weather; maintenance; crew-placarding; lengthy sit times; de-icing etc. On the third day of the trip; we were waiting in line for departure on [Runway] XXL at ZZZ; when the tower informed us that the operation was shut down for a 'deep-cleaning' at ZZZ1 Center.  Having personally experienced the same the same scenario last year when both the ZZZ2 Tower and ground were shut down for a COVID spread throughout their Tower; it didn't take long for us to figure out the reason for the closure.Like everyone one else in our situation; we opened up the FOM and began compliance with the notification processes for the passengers; the Flight Attendants; and ZZZ Ops. My First Officer (FO) and I immediately began working the 14 hour duty day issue; (FO A was my second FO during the course of the trip; and he had a less restrictive duty day constraint than I did).  After nearly two hours at the hold short line; we began the process of finding a gate; with the intent to avoid the prospective government fines levied for lengthy delays. It was the usual chaos; with ZZZ Ops being overwhelmed by this unforeseen event.  As we approach the two hour FOM deadline for locating a gate; we were assigned DXX via ACARS.  While taxiing to the gate; we made multiple attempts to get guidance from Ops; Ramp; Dispatch; etc.; to see what the intent was for the passengers; my crew; and the aircraft. We were unable to get any specific guidance. Following our arrival at the gate; an Agent opened the main door; and told us that the flight would be cancelled. As directed by the agent; the passengers disembarked with their bags. Since we had seen no changes to our crew schedule; nor had we received any kind of communication from crew tracking; we assumed that the agent was correct regarding the cancellation; and as such; we began reviewing our required duty time obligations. Absent any further guidance; we subsequently put the aircraft 'to bed;' and once again we attempted to contact crew tracking; (no luck there).  Rather than exit into the terminal; we elected to continue to wait on the aircraft.After 20 minutes or so; a new Agent came down the bridge; and asked me if we were ready to board the aircraft. Needless to say; I was a bit astonished.  I asked her what the plan was; and she said that we were going to resume the flight to ZZZ3; ASAP.  I reminded her that the airspace was still closed; and that we had not received any contact from either dispatch or tracking; regarding an updated release; and that we would need additional fuel; lavatory/water service; and a resupply of the delay rations that the Flight Attendants had used for the passengers during our time spent waiting on the taxiway. I also told her that both of us; along with two of the Flight Attendants had duty-time issues that we have to calculate and resolve before departure.  She promptly replied and asked me; 'Captain are you refusing to board the aircraft?'I immediately realized that this was the standard pass-the buck/assign the delay language; that some Agents use in an attempt to intimidate Pilots. I took several deep breaths; before I stated to her in no uncertain terms; that we would need to at least begin to address the aforementioned issues; before we would be comfortable boarding the aircraft again.  Her reply was; 'Captain; are you refusing to board the aircraft?'  I answered that until we get some of these issues resolved; yes.  What was clear to myself; my FO and the number one Flight Attendant; is that this was clearly an attempt at pilot-pushing. [In my opinion]; this Agent had one concern; and that was to make sure that these passengers would become someone else's problem; (namely ours).Long story short; and after significant efforts by all involved; we reconstituted the flight and determined that without further lengthy ground delays that we would likely arrive in ZZZ3 within our respective 14 hour duty day window. We then performed our usual checklists; flows; refueling; new clearance etc.After push-back; start and taxi instructions were received; I made my first mistake of the flight; and turned in the direct opposite direction of ground's instructions on the taxi clearance. It was at this point that I realized I was a lot more tired than I thought.  My FO and I discussed this; and we agreed that though we were both somewhat tired; it was safe to proceed; and that we should just take extra time and precautions going forward.Mistake number two on my part was that when ATC changed our departure STAR; we briefed it at the gate; had it up on our iPads; but I had failed to enter it in the MCDU. After wheels up; ATC gave us direct-to clearance to a fix that wasn't on the legs page. My FO quickly realized that I hadn't entered the new departure STAR; and he rapidly remedied it on the MCDU. I was mad at myself for making this series of unprecedented and inexplicable mistakes. Those mistakes continued as we descended on the type of complex STAR with a series of 'at or above' altitude constraints; that confounds the logic on some of the older 'Basic' airplanes.Needless to say; we landed safely in ZZZ3 later that evening. After block-in; I determined that I was within my duty legality; by 20 minutes or so. It had been a very long day.  We had departed ZZZ4 that morning before the sun had risen; and we had left the gate at ZZZ for the second time; well after the sun had set. In summary; I had made many embarrassing operational mistakes during the course of the last leg; beginning with my pre-flight; push back; all the way through the descent into ZZZ3.  The only explanation for my numerous mistakes was fatigue. In short; I will never; ever; again allow the 'system' to push to me beyond my own personal safety limits. I will take my First Officers counsel more seriously when it comes to considering just how tired we are.Additional factors include that when you consider the cumulative effects of four and five day trips on us; along with a 14 hour duty period; it can be well beyond the average pilot's limitations to safely operate.  And while I don't blame the agent personally; (like everyone else; she was just doing the job in the manner that she was trained); and like everyone else she's just under time pressure.  As time has gone by at our company; it has become clear to me; that the safety culture at the top of this airline; is in many respects; mostly honored and kept in place; by those who of us; who are at the pointy end of the spear.In retrospect; the main causal factor was fatigue due to a lengthy delay.Two suggestions.  The first is that [in my opinion]; we need to take into account the cumulative effect of a lengthy four and five day trip on pilot fatigue.  The other issue is Gate Agent conduct and verbiage regarding flight Ops as it regards to boarding the passengers.




Synopsis: Air Carrier Captain reported several operational errors occurring after a long ground delay long due to an 'ATC Zero' event.