Narrative:

After being cleared for takeoff on runway xxl; I began to push the thrust levers forward; noted the (left) engine N1 stabilized at 40 percent; then continued to advance the thrust levers to take-off thrust. As the engine spooled up; the aircraft began to yaw and I immediately reduced the thrust to idle; realizing we had not started the second engine. During the pre-departure briefing; I had indicated that we would taxi on two engines since it would be a short taxi from our gate to the runway. Later; after we had pushed back from the gate and started the first engine; I failed to direct the first officer to start the second engine before we began to taxi. I believe this first error occurred because I was preoccupied; considering when I would call for certain checklists (the runway/performance change checklist and the before takeoff checklist); since the taxi would be so short. When I called for the before takeoff checklist; I recall checking the takeoff parameters above the engine indications; but failed to see that the second engine was not running. I always re-scan particular items when ATC clears us for takeoff or to 'line up and wait'; one of these being the engine indications; to ensure that both are running as we cross the runway hold-short lines. Another item I scan at this time is the FMA (flight mode annunciator); to ensure that I have pressed the toga button and the appropriate modes are displayed. In this case; I saw that the FMA was not populated; so I pressed the toga button to correct the problem. I believe this distracted me from re-scanning the engine indications as I was mentally reprimanding myself for forgetting to populate the FMA. It is very odd that I did; in fact; watch the left engine spool up without noticing that the right engine was not running. I had never realized that I have been fixating on the left engine during takeoff.the main causes are short taxi time; preoccupation with upcoming tasks; and failure to redirect my attention back to planned tasks after being distracted. The main things I need to do are to become more deliberate in ensuring tasks are completed and making certain I return my attention to the tasks at hand when I am distracted.

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Original NASA ASRS Text

Title: EMB-175 Captain reported failing to complete the checklists prior to beginning takeoff with one engine still not started.

Narrative: After being cleared for takeoff on Runway XXL; I began to push the thrust levers forward; noted the (left) engine N1 stabilized at 40 percent; then continued to advance the thrust levers to take-off thrust. As the engine spooled up; the aircraft began to yaw and I immediately reduced the thrust to idle; realizing we had not started the second engine. During the pre-departure briefing; I had indicated that we would taxi on two engines since it would be a short taxi from our gate to the runway. Later; after we had pushed back from the gate and started the first engine; I failed to direct the First Officer to start the second engine before we began to taxi. I believe this first error occurred because I was preoccupied; considering when I would call for certain checklists (the runway/performance change checklist and the before takeoff checklist); since the taxi would be so short. When I called for the before takeoff checklist; I recall checking the takeoff parameters above the engine indications; but failed to see that the second engine was not running. I always re-scan particular items when ATC clears us for takeoff or to 'line up and wait'; one of these being the engine indications; to ensure that both are running as we cross the runway hold-short lines. Another item I scan at this time is the FMA (Flight Mode Annunciator); to ensure that I have pressed the TOGA button and the appropriate modes are displayed. In this case; I saw that the FMA was not populated; so I pressed the TOGA button to correct the problem. I believe this distracted me from re-scanning the engine indications as I was mentally reprimanding myself for forgetting to populate the FMA. It is very odd that I did; in fact; watch the left engine spool up without noticing that the right engine was not running. I had never realized that I have been fixating on the left engine during takeoff.The main causes are short taxi time; preoccupation with upcoming tasks; and failure to redirect my attention back to planned tasks after being distracted. The main things I need to do are to become more deliberate in ensuring tasks are completed and making certain I return my attention to the tasks at hand when I am distracted.

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.