Atl air carrier awaiting departure confused ATC's instruction and entered the runway without authori...

Narrative:

We were number one for take off and from our vantage point; no other traffic was seen for our runway. We heard and read back 'line up and wait runway 26L.' the cockpit was orderly and sterile with no noted distractions. Checklists completed and when we crossed into position we were told by tower that they intended the line up and wait for a rj call sign. Tower advised us to briefly hold; line up and wait; and then cleared us for takeoff. I do not believe there was any loss of separation. Why confusion occurred; my opinion; possible expectation bias where we were clearly number one and we understood we were cleared into position to line up and wait. We were the only aircraft taxi[ing] toward takeoff that we could see on either side of the departure end of runway. There were no obvious distractions or abnormal conditions. All three packs were operating and a slightly louder than normal noise level; but both crew members agreed that noise was not any reason and until tower questioned our action; there was not any doubt. How to prevent future occurrences? Not sure except to somehow trap that error between tower and our crew. Maybe runway hold lights from our side of the runway. We believed we heard clearance for our airplane and clearly read back the clearance. There was no blocked transmissions; our read back was clear. I am particularly detailed on such clearances and pay attention. Cockpit was sterile and orderly flow of tasks and checklists. Read back or incorrect read back seems to be no excuse to the FAA; but it is the pilot's signal of his intention. I suspect the rj airplane; which was closer to the ramp; was not on frequency yet at time of our read back; so tower heard our read back maybe being from the rj similar call sign?

Original NASA ASRS Text

Title: ATL Air Carrier awaiting departure confused ATC's instruction and entered the runway without authorization; indicating a similar call sign may have been the primary causal factor in this event.

Narrative: We were number one for take off and from our vantage point; no other traffic was seen for our runway. We heard and read back 'Line Up and Wait Runway 26L.' The cockpit was orderly and sterile with no noted distractions. Checklists completed and when we crossed into position we were told by Tower that they intended the line up and wait for a RJ call sign. Tower advised us to briefly hold; line up and wait; and then cleared us for takeoff. I do not believe there was any loss of separation. Why confusion occurred; my opinion; possible expectation bias where we were clearly number one and we understood we were cleared into position to line up and wait. We were the only aircraft taxi[ING] toward takeoff that we could see on either side of the departure end of runway. There were no obvious distractions or abnormal conditions. All three packs were operating and a slightly louder than normal noise level; but both crew members agreed that noise was not any reason and until Tower questioned our action; there was not any doubt. How to prevent future occurrences? Not sure except to somehow trap that error between Tower and our crew. Maybe runway hold lights from our side of the runway. We believed we heard clearance for our airplane and clearly read back the clearance. There was no blocked transmissions; our read back was clear. I am particularly detailed on such clearances and pay attention. Cockpit was sterile and orderly flow of tasks and checklists. Read back or incorrect read back seems to be no excuse to the FAA; but it is the pilot's signal of his intention. I suspect the RJ airplane; which was closer to the ramp; was not on frequency yet at time of our read back; so Tower heard our read back maybe being from the RJ similar call sign?

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	923596
Time
Date	201012
Local Time Of Day	0001-0600
Place
Locale Reference	ATL.Airport
State Reference	GA
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Widebody Transport
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 75 Flight Crew Total 6500 Flight Crew Type 2700
Events
Anomaly	Deviation - Procedural Clearance Ground Incursion Runway

Atl air carrier awaiting departure confused ATC's instruction and entered the runway without authorization; indicating a similar call sign may have been the primary causal factor in this event.