Date: 201407
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B777 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb; Takeoff / Launch; Taxi
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Confusion; Communication Breakdown; Distraction
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight; Taxi
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: During preflight at the gate; both the First Officer and I were explaining to our two Reserve IRO's the data link procedures for attaining a clearance at our departure airport. The proper procedures were used; the data link appeared to work fine and the clearance was requested. I then left the cockpit and upon return got our briefs completed; ran the required checklists and felt ready for pushback and start. We started and were heading over to 22R for a full runway departure. Approaching the hold short line; Tower told us to check our transponder ON and we were subsequently cleared [to] line up and wait. The First Officer verified the transponder WAS on but on second glance; noted the code was 0000. I asked the IRO to grab the clearance printout and verify the squawk. He couldn't locate it so we simply asked the Tower to verify our code. He quickly gave it to us and cleared us for takeoff. At 900 feet Departure cleared us to 6;000 feet and we were on our way. I then checked for the paper clearance and when unable to locate it; I went to the computer. It was not there. Realizing that we may not have copied the clearance; I immediately checked with ATC/ Departure to ensure they had our flight plan. They said yes; no problem and we continued on our way with no additional problems.


Second narrative: On taxi out just prior to reaching the runway Ground Control asked us to turn on our transponder. The First Officer stated it was on but noticed no squawk code had been entered (aka squawking all zeros). He asked Ground to verify the squawk and entered it in the transponder. At that point we had been switched to Tower who cleared us into position and hold and then cleared for takeoff. After airborne we began to look for the written PDC which was not found. There then was a discussion if anyone remembered a clearance ever coming up via ACARS. After looking at the reviewed ATC communication in ACARS we realized we hadn't received our clearance before calling for taxi. We were all surprised that we were able to push; taxi; takeoff all without ever having received our clearance. The IRO called the departure airport Clearance and verified our clearance. We continued on without incident.


Synopsis: A B777 Captain instructed the IRO's about data link clearance procedures then left the cockpit only to discover during taxi that the Clearance PDC had not been obtained because no transponder code was available.