Date: 202003
Local time of day: 0001-0600
Location: SJC.Airport, CA
Flight conditions: VMC
Light: Dawn
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Fatigue; Situational Awareness
Second reporter function: Captain; Pilot Flying
Anomaly: Airspace Violation All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: Departure on this flight occurs well before the Control Tower opens. While preflighting; the aircraft received and printed a PDC with a clearance that deviated slightly from our filed plan. We inputted and cross-verified the clearance and the squawk code. This was the first time for both of us operating out of SJC as an uncontrolled field and we carefully reviewed and briefed the 10-9 and 10-7 for any pertinent information. I remember commenting that it was odd getting a PDC with the Tower closed and the Captain agreed that it was unusual. We made all necessary calls on CTAF as we pushed; taxied; and took off. When I called NorCal for the first time airborne; the Controller sounded confused; asked for an ident and told us to remain VFR; then told us to standby for our route clearance. I responded that we would stay VFR and that we had received clearance via PDC. He said they didn't have that capability; then read us pretty much the same clearance and same code. He instructed us in the future that we needed NorCal permission to depart IFR. At no time were we in IMC condition or near any other traffic. Challenging morning! This is a XA:XX scheduled departure that followed a minimum rest overnight. Preflight prep was a bit of a struggle. Neither of us could get flight view to work for some time until we utilized the hotspot; then could not get weather as the ASOS frequency only broadcast NOTAMs; until we figured out to call the number for the ASOS on the 10-7. We were both very familiar with SJC but neither had operated with ATC closed. We focused pretty hard on all the unusual stuff making sure we didn't miss obstacle procedure; noise abatement or a required runway but utterly missed the fact that the PDC did not apparently constitute an IFR clearance to depart. The PDC was 'normal' and did not contain a wheels up or any unusual instructions. Had we not received the PDC; we would naturally have contacted NorCal just like at the dozens of uncontrolled fields we go to; but for some reason having the PDC; along with everything else did not trigger that instinct that early in the morning. This should be a schedule red alert reminding pilots about operating outside ATC hours at this airport. I'm not sure where the PDC came from; but I can see this confusing a lot of people. Why one was generated at all is my biggest question.


Second narrative: On power up of aircraft at SJC; a PDC printed out and we entered this flight plan into the FMS. The Tower was closed and we commented to each other that it seemed odd that we got a PDC to begin with. We both looked very thoroughly through all of our documentation (10-7; 10-9; release notes and NOTAMs) for any information on this and only saw that the Aircraft X was exempt from the SJC curfew. We figured that this was our ATC clearance so we taxied out and took off from SJC and contacted NorCal Departure. NorCal told us to remain VFR and then gave us our clearance and squawk code which matched the PDC. It was VMC conditions and we told NorCal that since we received a PDC we thought we were cleared to depart SJC. He said that the departure facility did not have PDC capability and that next time we should contact them on the ground for our clearance and release. We then continued the flight with no more difficulties. This flight departed well before the Tower opened and we had a reduced rest over night the night before. Upon trying to initialize our iPads we were having trouble with the flight view program. It was not allowing either of us to enter the schedule to scan the Q codes. We turned on the portable WiFi device and this allowed us to initialize. This took extra time and we were already slightly fatigued from the prior nights short rest. The WX (weather) was also not being transmitted over the ATIS frequency. We called the AWOS phone number and got the one-minute WX. This seemed odd to us that the WX station was not broadcasting good information. All of these things seemed odd to us and were a cause for fatigue. There was also no guidance in any of our SJC information on contacting ATC for clearance even though we received a PDC. I've never been to an airport that I received a PDC before while the Tower was closed. Put in our company manuals and Jepp documents some information to contact ATC before departure even if you get a PDC. Had I not received a PDC I would have had to contact ATC to get my clearance and release. It was very confusing to have a PDC at a closed Tower facility. There should be a red exclamation mark on our schedules about departing SJC before the Tower is open while being issued a PDC.


Synopsis: Air carrier flight crew reported receiving a PDC from SJC Control Tower that was not open and departing; without calling the overlying TRACON.