Date: 201906
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 20
Light: Daylight
Aircraft: Cessna Citation Undifferentiated or Other Model
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Climb
Airspace: Class E ZZZ
ATC / advisory: TRACON ZZZ
Reporter organization: Corporate
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Workload; Situational Awareness; Confusion
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Airspace Violation All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I am new pilot at this company. When our departure time arrived; I attempted to get an IFR clearance from Departure Control. After making initial contact with them; I received no callback with my clearance after several minutes. Our passengers had arrived and started boarding the aircraft. It was hot outside and inside the aircraft. I went ahead and got the engines started and advised the other pilot (one of our senior captains who was flying as my First Officer) that I was still waiting for our IFR clearance when he arrived on the flight deck after closing the passenger door. He said that he would get the clearance. He then called Departure Control and copied down the clearance and read it back. It was a 'Hold for Release' clearance. I overheard him read back the clearance as I was finishing up some pre-flight checks. We each performed pre-flight checks and duties as we taxied towards the takeoff runway. As we neared the end of the takeoff runway; I asked the other pilot; 'Are we released.' I was feeling uneasy about this as I had not heard us receive an IFR release for takeoff. His reply was 'Yes.' At this point; I questioned my own situational awareness and figured that I had missed a radio call that he had made; perhaps on the other radio; and that if he said we were released then we were released. We taxied out onto the departure runway; took off and followed the clearance of runway heading and a climb to 2000 feet. The other pilot contacted Departure Control immediately after departure. Prior to entering the Class C airspace that is above; radio communication was established with Departure Control by the other pilot. When the other pilot called Departure Control; they said that we had not been released for takeoff. The weather at the time was severe clear and unrestricted visibility. There was also a high volume of VFR traffic in the pattern at the time. There were no known traffic conflicts and there was no conflicting traffic on the TCAS.


Second narrative: Taxing out I requested clearance on remote frequency. The Captain was taxiing and monitoring CTAF. I received a clearance and was also told to call for release when number 1. When I wrote the clearance down I failed to write 'hold for release'. Our clearance was fly runway heading; maintain two thousand and hold for release. There was one airplane in front of us departing for touch and go's. Meanwhile another airplane was on final for touch and go's. Concentrating on the aircraft in the pattern; I just forgot about getting a release. The Captain even asked me if we were released. I said 'yes'. I think getting clearances on cell phones made me think in the back of my mind that we were released. Because on the phone you won't get a clearance until you're released and you will get a void time. It was my mistake and take full responsibility. We departed and I contacted Departure immediately afterward prior to entering Class C which is above the airport. He asked me if we had a clearance and were released. I knew right then my mistake. I told him we received a clearance but I forgot to get a release. The weather was clear and 20 miles visibility. He gave us a right turn to 080 degrees and told us to climb to 3000 feet then handed us off to the next controller. This controller gave me a phone number to call for a possible deviation. After that he gave us a higher altitude and handed us off to Center. I believe my not writing 'hold for release' on my paper was a major case for me forgetting. Also; concentrating on aircraft in the pattern and trying to fit in the flow may also have contributed. The fact that clearances on a phone may also have been in the back of my mind that we were good to go. I think that if they would not give a clearance until you can be released would keep this situation from ever happening again. There was no known conflict indicated by the controller or TCAS.


Synopsis: Citation flight crew reported taking off from a non-towered airport without obtaining a release as instructed in their clearance.