Narrative:

Previous crew left #2 engine operating. I changed aircraft and came to this gate to operate the last turn of my trip. [I] talked with the prior crew during swap then grabbed my vest and went outside to walk around the aircraft. Upon reaching the right side of the aircraft and getting to the place in front of the wing where I would normally look up into the engine to look at the fan blades; the fueler lifted up his pull cord to let me pass underneath. Instead of finishing my visual check; I acknowledged the fueler and ducked under the cord then went straight into inspecting the wing. After I had inspected the main landing gear; I looked at the engine nacelle but did not look into the fan blades. At the same time as I was completing the walk around; the packs and APU of my aircraft was operating; the additional sound of the engine at idle was not noticed. [I] completed the rest of the walk around as usual and got into the plane trying to accomplish the quick turn to get the flight out.we pushed back and I started the #1 engine. Once that was accomplished; indications on the EICAS were out of place for only one engine running. That is when we recognized that #2 was already running. The distraction of the fueler helping me get past him took me out of my typical routine and had me miss looking into the engine and seeing fan blades. Upon settling into the cockpit; I hurried into getting the plane ready and did not pay enough attention to what the EICAS was displaying about the #2 engine and missed those indications as well. We recognized the event but at that point; the best course of action was to continue the flight as there was no continuing danger and the plane was in a standard configuration now with both engines running.since the event; I have actively changed my walk around to verify that the engines are not running both from the front of the wing were I can see the fan blades easier and behind the wing looking up into the nacelle further. I also have slowed down my scans in the cockpit to not miss indications on the EICAS.

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Original NASA ASRS Text

Title: EMB-145LR First Officer reported that the #2 engine had been left running by the previous flight crew and went unnoticed through the walk around and pushback.

Narrative: Previous crew left #2 engine operating. I changed aircraft and came to this gate to operate the last turn of my trip. [I] talked with the prior crew during swap then grabbed my vest and went outside to walk around the aircraft. Upon reaching the right side of the aircraft and getting to the place in front of the wing where I would normally look up into the engine to look at the fan blades; the fueler lifted up his pull cord to let me pass underneath. Instead of finishing my visual check; I acknowledged the fueler and ducked under the cord then went straight into inspecting the wing. After I had inspected the main landing gear; I looked at the engine nacelle but did not look into the fan blades. At the same time as I was completing the walk around; the packs and APU of my aircraft was operating; the additional sound of the engine at idle was not noticed. [I] completed the rest of the walk around as usual and got into the plane trying to accomplish the quick turn to get the flight out.We pushed back and I started the #1 engine. Once that was accomplished; indications on the EICAS were out of place for only one engine running. That is when we recognized that #2 was already running. The distraction of the fueler helping me get past him took me out of my typical routine and had me miss looking into the engine and seeing fan blades. Upon settling into the cockpit; I hurried into getting the plane ready and did not pay enough attention to what the EICAS was displaying about the #2 engine and missed those indications as well. We recognized the event but at that point; the best course of action was to continue the flight as there was no continuing danger and the plane was in a standard configuration now with both engines running.Since the event; I have actively changed my walk around to verify that the engines are not running both from the front of the wing were I can see the fan blades easier and behind the wing looking up into the nacelle further. I also have slowed down my scans in the cockpit to not miss indications on the EICAS.

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.