Narrative:

Night time takeoff runway 23. Captain with first officer on first flying leg of IOE and two relief pilots for the flight. We were cleared onto the runway 23 after a landing 737. First officer taxied onto the runway for takeoff. Once aligned for takeoff I took control of the throttles. At this point I thought we were cleared for takeoff but apparently wasn't and advanced the power to 70% and pressed toga. At about that same time a relief pilot alerted the flying pilots that the other plane that had just landed was cleared to back track to east on runway 23; as well as the tower alerting us to hold position. I disconnected the autothrottles and immediately brought them to idle. We were approximately 30 knots and had used up approximately 200 to 400 feet of runway. The back tracking 737 entered the runway and exited at east. Because we had started the takeoff roll and used up some of the usable runway it was decided to taxi down runway 23 to east and come back around to line up on runway 23 full length. Fuel was not an issue.looking back; somehow the clearance to takeoff or the non-clearance was lost in the translation. The controllers in fnlu most often use non-standard phraseology; with an accent not easily understood. Coupled with higher than normal workloads due to a new hire first leg. The flight was late and had been delayed from the previous day. Assumed situational awareness with the airport and runway environment. Generally in past practice; fnlu hold the landing traffic in the holding bay after landing and does not have 2 planes on the runway at the same time.what 'saved' the situation was good CRM and situational awareness of the relief pilots.

Related reports:

Google
 

Original NASA ASRS Text

Title: Air carrier flight crew reported beginning their takeoff roll too early with an aircraft that was cleared to back taxi was occupying the runway.

Narrative: Night time takeoff Runway 23. Captain with FO on first flying leg of IOE and two relief Pilots for the flight. We were cleared onto the Runway 23 after a landing 737. FO taxied onto the runway for takeoff. Once aligned for takeoff I took control of the throttles. At this point I thought we were cleared for takeoff but apparently wasn't and advanced the power to 70% and pressed TOGA. At about that same time a relief pilot alerted the flying Pilots that the other plane that had just landed was cleared to back track to E on Runway 23; as well as the Tower alerting us to hold position. I disconnected the autothrottles and immediately brought them to idle. We were approximately 30 knots and had used up approximately 200 to 400 feet of Runway. The back tracking 737 entered the Runway and exited at E. Because we had started the takeoff roll and used up some of the usable Runway it was decided to taxi down RWY 23 to E and come back around to line up on RWY 23 full length. Fuel was not an issue.Looking back; somehow the clearance to Takeoff or the non-clearance was lost in the translation. The controllers in FNLU most often use non-standard phraseology; with an accent not easily understood. Coupled with higher than normal workloads due to a new hire first leg. The flight was late and had been delayed from the previous day. Assumed situational awareness with the airport and runway environment. Generally in past practice; FNLU hold the landing traffic in the holding bay after landing and does not have 2 planes on the runway at the same time.What 'saved' the situation was good CRM and situational awareness of the relief pilots.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.