Narrative:

Last leg flown to completion. Taxi in to the gate included three minute time clock for number two engine shutdown. Arrived at gate XXX safety zone. Upon turning into the safety zone; we had to stop briefly for equipment to be moved. After movement we proceeded into gate safely. Parking brake set; number one engine shut down; ground personnel cleared into zone; and parking checklist was started. During checklist; the ground crew asked if we were receiving ground power. Checklist was fragmented as a result. Ground power was established and APU was shut down. I got out of the seat and began final shutdown procedures. Time elapsed was approximately three minutes. First officer remained seated and was completing post flight duties. My attention was raised by a flashing light from down on the ground. Maintenance and ramp personnel alerted us to the fact the number two engine was still running. We immediately shut it down. Maintenance personnel boarded the flight deck and were quite emotional about the event. Discussion ensued and an attempt at an explanation was given. Conversation was very brief. Normal hand off to maintenance personnel then completed.first; the distraction in the safety zone prevented number two shut down. Second; ground power discussion prevented full completion of shutdown checklist which would have caught the running engine. Noise in the cockpit did not alert us. The correction? Just have to maintain the ultimate concentration anytime we are in the safety zone. Checklist completion is of the utmost importance. I failed as a pilot in command; we failed as a crew and it was a huge learning lesson all around.

Related reports:

Google
 

Original NASA ASRS Text

Title: A B737-700 flight crew taxied into the gate; shutdown #1 engine; but mistakenly failed to shut down the #2 engine. The Captain finally shutdown the engine after ramp agents notified the crew twice about the problem which the crew misunderstood as a request to confirm ground power ON.

Narrative: Last leg flown to completion. Taxi in to the gate included three minute time clock for number two engine shutdown. Arrived at Gate XXX Safety Zone. Upon turning into the Safety Zone; we had to stop briefly for equipment to be moved. After movement we proceeded into gate safely. Parking brake set; number one engine shut down; Ground Personnel cleared into zone; and Parking Checklist was started. During checklist; the Ground Crew asked if we were receiving ground power. Checklist was fragmented as a result. Ground power was established and APU was shut down. I got out of the seat and began final shutdown procedures. Time elapsed was approximately three minutes. F/O remained seated and was completing post flight duties. My attention was raised by a flashing light from down on the ground. Maintenance and Ramp Personnel alerted us to the fact the number two engine was still running. We immediately shut it down. Maintenance Personnel boarded the flight deck and were quite emotional about the event. Discussion ensued and an attempt at an explanation was given. Conversation was very brief. Normal hand off to Maintenance Personnel then completed.First; the distraction in the Safety Zone prevented number two shut down. Second; ground power discussion prevented full completion of Shutdown Checklist which would have caught the running engine. Noise in the cockpit did not alert us. The correction? Just have to maintain the ultimate concentration anytime we are in the Safety Zone. Checklist completion is of the utmost importance. I failed as a Pilot in Command; we failed as a Crew and it was a huge learning lesson all around.

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.