Narrative:

During taxi-out we received a runway change. I had originally pulled data for 17R which had flaps 1 and a flex temp of 43. When we received clearance for runway 25 I sent for data that came back with flaps 2 and a flex temp of 45. I briefed the configuration change as well as the t-procedure and loaded the slightly faster speeds in the box but left the original lower flex temp. While accomplishing all this on a shortened taxi; a new maintenance release came for a maintenance problem we had dealt with after pushback. At the same time; I noted that we still didn't have final weights and sent the ACARS codes for that. Somehow in the midst of all of this I forgot to reposition the flaps to 2 and neither of us caught the mistake on the before takeoff checklist. We took off uneventfully and didn't notice the mistake until I was about to call for flaps 1 at acceleration altitude. I later pulled data for a flaps 1 takeoff on runway 25 and noted we were legal with the configuration and speed settings we departed with; but had obviously committed a serious breach of SOP.when I think back on how this could have happened I realized there were several contributing factors: 1. Fatigue: this was day 6 of a reserve stretch that had a lot of very early departures; and a late afternoon short-call period thrown in to affect my sleep patterns. With the early wake-up required for our show on this my last day; I was tired at this point and ready to get home. 2. Multiple distractions: a maintenance problem; runway change; late weights; a new mrd printing while making changes to our runway data and a rushed checklist were a classic setup for something to go wrong. 3. Checklist use and design: my habit has been to position my FMGC for the departure verification portion of the before takeoff checklist and let the captain pull the performance page for the flaps portion of the checklist. After this incident I will probably reference both pages on my side to make it easier to backup the captain. For this flight I ran the checklist down to manifest changes while waiting for final weights. I won't break the checklist flow like this again even though it is permitted by SOP. As to checklist design; I think our checklists should have the flaps line after manifest changes but just before trim; weights and speeds. That way if there are manifest changes that affect the performance data; it offers one more chance to catch a mistake. In our case I thought I had selected flaps 2 before starting the checklist; but didn't look at the captain's performance page to compare what was in the box with what we had selected with the flap lever. 4. Inappropriate multiple-tasking: my nature is to try to get it all done as efficiently and quickly as possible; even if it means multitasking. This incident wouldn't have happened if I had run each task to completion before shifting my attention to another task. Obviously some tasks can and should be done simultaneously; but runway data and configuration tasks should stand alone and be run to completion. On my last check ride we talked about takeoff configuration errors in particular. Back then I was sure it couldn't happen to me......

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Original NASA ASRS Text

Title: An air carrier First Officer reported taking off from DEN with an incorrect flap setting.

Narrative: During taxi-out we received a runway change. I had originally pulled data for 17R which had Flaps 1 and a Flex temp of 43. When we received clearance for Runway 25 I sent for data that came back with Flaps 2 and a Flex temp of 45. I briefed the configuration change as well as the T-procedure and loaded the slightly faster speeds in the box but left the original lower flex temp. While accomplishing all this on a shortened taxi; a new maintenance release came for a maintenance problem we had dealt with after pushback. At the same time; I noted that we still didn't have final weights and sent the ACARS codes for that. Somehow in the midst of all of this I forgot to reposition the flaps to 2 and neither of us caught the mistake on the before takeoff checklist. We took off uneventfully and didn't notice the mistake until I was about to call for Flaps 1 at acceleration altitude. I later pulled data for a Flaps 1 takeoff on Runway 25 and noted we were legal with the configuration and speed settings we departed with; but had obviously committed a serious breach of SOP.When I think back on how this could have happened I realized there were several contributing factors: 1. Fatigue: This was day 6 of a reserve stretch that had a lot of very early departures; and a late afternoon short-call period thrown in to affect my sleep patterns. With the early wake-up required for our show on this my last day; I was tired at this point and ready to get home. 2. Multiple distractions: A maintenance problem; runway change; late weights; a new MRD printing while making changes to our runway data and a rushed checklist were a classic setup for something to go wrong. 3. Checklist use and design: My habit has been to position my FMGC for the departure verification portion of the before takeoff checklist and let the Captain pull the Performance page for the Flaps portion of the checklist. After this incident I will probably reference both pages on my side to make it easier to backup the Captain. For this flight I ran the checklist down to manifest changes while waiting for final weights. I won't break the checklist flow like this again even though it is permitted by SOP. As to checklist design; I think our checklists should have the Flaps line after manifest changes but just before trim; weights and speeds. That way if there are manifest changes that affect the performance data; it offers one more chance to catch a mistake. In our case I thought I had selected Flaps 2 before starting the checklist; but didn't look at the Captain's Performance page to compare what was in the box with what we had selected with the flap lever. 4. Inappropriate multiple-tasking: My nature is to try to get it all done as efficiently and quickly as possible; even if it means multitasking. This incident wouldn't have happened if I had run each task to completion before shifting my attention to another task. Obviously some tasks can and should be done simultaneously; but Runway data and configuration tasks should stand alone and be run to completion. On my last check ride we talked about takeoff configuration errors in particular. Back then I was sure it couldn't happen to me......

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.