A B737-700 first officer reported that because his before taxi task flow was interrupted he failed t...

Narrative:

After being pushed from the gate and starting engines we started the 'before taxi checklist'. When we got to the point of the checklist that said 'recall' we found a 'pack trip off' light illuminated. We stopped at that point and completed the QRH checklist for that item with no further problems. Because of this distraction we failed to complete the next step at the gate that called for 'flaps' which should have been set to '1'. During the taxi out we completed the 'before takeoff checklist' which called for 'flaps and takeoff warning' and I witnessed the captain push the throttles forward without any warnings. We both failed to check the flap indicator for some reason (I still do not understand how I missed that because I always do check the flap indicator at this time). We were advised to take the runway and 'line up and wait'. We were then cleared to takeoff and that is when the captain pushed the throttle up for takeoff. As he did that we got the 'takeoff configuration warning horn' at which time we aborted the takeoff immediately. Tower was advised and they cleared us up to the next intersection to exit runway. After we exited the runway we did the 'after landing checklist' and then went back to check the entire checklist to make sure everything was completed and that is when we put the flaps to '1' and completed the 'before takeoff checklist' and got back in line for takeoff. No other issues after that. Just need to make sure to check the flaps indicator every time. I do this all the time and I just do not know how I missed it this time. I have a flow that I use to check the takeoff page for flap setting; flap indicator and the actual flap handle to make sure they are all in the right location or setting. I still just don't know how we missed this. I am a pilot that uses the checklist every time and never thought I would miss something like this. I just can't believe I let this happen. It will never let this happen again because I will make it a priority even more so now.

Original NASA ASRS Text

Title: A B737-700 First Officer reported that because his Before Taxi task flow was interrupted he failed to extend the flaps so when the thrust levers were advanced for takeoff the Takeoff Warning Horn sounded and the Captain rejected the takeoff.

Narrative: After being pushed from the gate and starting engines we started the 'Before Taxi Checklist'. When we got to the point of the checklist that said 'recall' we found a 'Pack Trip Off' light illuminated. We stopped at that point and completed the QRH checklist for that item with no further problems. Because of this distraction we failed to complete the next step at the gate that called for 'Flaps' which should have been set to '1'. During the taxi out we completed the 'Before Takeoff Checklist' which called for 'Flaps and Takeoff Warning' and I witnessed the Captain push the throttles forward without any warnings. We both failed to check the flap indicator for some reason (I still do not understand how I missed that because I always do check the flap indicator at this time). We were advised to take the runway and 'line up and wait'. We were then cleared to takeoff and that is when the Captain pushed the throttle up for takeoff. As he did that we got the 'Takeoff Configuration Warning Horn' at which time we aborted the takeoff immediately. Tower was advised and they cleared us up to the next intersection to exit runway. After we exited the runway we did the 'After Landing Checklist' and then went back to check the entire checklist to make sure everything was completed and that is when we put the flaps to '1' and completed the 'Before Takeoff Checklist' and got back in line for takeoff. No other issues after that. Just need to make sure to check the flaps indicator every time. I do this all the time and I just do not know how I missed it this time. I have a flow that I use to check the takeoff page for flap setting; flap indicator and the actual flap handle to make sure they are all in the right location or setting. I still just don't know how we missed this. I am a pilot that uses the checklist every time and never thought I would miss something like this. I just can't believe I let this happen. It will never let this happen again because I will make it a priority even more so now.

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	952652
Time
Date	201105
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Component
Aircraft Component	Flap Control (Trailing & Leading Edge)
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Commercial
Events
Anomaly	Deviation - Procedural Published Material / Policy

A B737-700 first officer reported that because his before taxi task flow was interrupted he failed to extend the flaps so when the thrust levers were advanced for takeoff the takeoff warning horn sounded and the captain rejected the takeoff.