Date: 202011
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Taxi
Reporter organization: Air Carrier
Reporter function: First Officer; Relief Pilot
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Training / Qualification; Communication Breakdown; Distraction
Second reporter function: Captain; Pilot Not Flying
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Returned To Gate; General Flight Cancelled / Delayed
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: I arrived at the aircraft as relief pilot an hour before takeoff for a cargo flight to ZZZZ. The FO was at the aircraft and had completed much of the cockpit preflight. Because it was a cargo flight I went through the cabin and secured the overhead bins and many of the storage /catering carts. The Captain arrived and we went through the standard cockpit flight preparation prior to departure. After we pushed from the gate and initiated the engine start; I realized I had not done the Pre-Fight Walk Around Inspection. I asked the FO if he had completed it and he said he had not. He thought I was doing that when I was actually securing the cabin for departure. I told the Captain I forgot to do the walk around. The Captain got clearance and we turned around on the ramp and went back into the gate. The Agent came back; hooked up the jet bridge and I went out and completed the walk around inspection. We re-accomplished all the pre-departure checks and ended up departing to ZZZZ about XX minutes late. Most of the delay was a result of getting personnel back to park us and recalling another push crew.I think that because it was a cargo flight; I was possibly distracted by some non-standard items in the cabin and got out of my habit pattern. Like most of us; I haven't been flying too much but the bottom line is that I simply forgot to do the walk around preflight and realized it after the push.In the future I will report to the FO that the walk around has been completed and as the FO I will verify with the relief pilot that it has been complete. I have been flying airplanes for XX years and have never forgotten to do a walk around inspection.


Second narrative: During the pushback from the gate; the flight crew realized a communication error occurred resulting in the non completion of the pre-flight walk around duties by a pilot. A return to a gate commenced to complete the required tasks. Contributing factors may have been one crew member being newly experienced to three-four pilot crew tasks combined with a multi month period of not working. Making the crew cross information in this specific area a mandatory portion of any preflight operations area briefing; crew text preflight contact; or aircraft boarding process.


Synopsis: Air carrier Relief Pilot and Captain reported forgetting to do the pre-flight walkaround and cited communication; distraction and lack of recent flying as contributing factors.