Narrative:

While in line (#18) for takeoff with the before takeoff checklist completed down to final items; we started to hear reports of wind shear on the tower frequency. There may have also been a wind shear advisory on the ATIS. The captain decided to change the takeoff thrust setting and use toga. I asked if he would also like to use flaps 2. He said yes and I requested flaps 2 takeoff data from the ACARS. While I was doing this the captain began reprogramming the perf page by entering 2 in the flap setting. When we received the takeoff data; we had a long discussion about what speeds he wanted for takeoff. He decided to use the max thrust v-speeds for V1 and vr and a speed of 142 for rotate. This speed was well below the 154 vr maximum listed on the data; but he chose it because it matched the 10 knot tailwind vr for a reduced takeoff (I guess this is his technique). I programmed the speeds into the perf page and shortly thereafter we departed 4L; rotating at 142 knots. At 800 feet afe; upon power reduction; the captain noticed and stated that the flaps were still at position 1 and that we had never set flaps 2. We discussed what had occurred and compared the speeds we had used with the flaps 1 data. It appeared that we rotated 4 knots below the rotate speed for flaps 1 reduced; but I didn't think to compare it to the vr speed on the toga thrust line for the flaps 1 data.the error was that we did not comply with the flight manual and repeat the before takeoff checklist after repositioning a flight control. Other contributing factors were my flow for setting the new flap position on the perf page followed by moving the flap lever to the proper position was interrupted by the captain selecting position 2 on the perf page; the extensive discussion on v-speeds; and the first time flying together with this out of domicile captain.

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Original NASA ASRS Text

Title: An A320 flight crew; number 18 for takeoff due to reported windshear; reports on takeoff and landing; wisely opted to change their takeoff configuration to flaps position two and TOGA power as a precaution. They programmed new performance numbers based on the new configuration but failed to repeat the before takeoff checklist after doing so. During climbout they realized they had not reset the flaps and they had remained in their original flaps one position.

Narrative: While in line (#18) for takeoff with the Before Takeoff Checklist completed down to final items; we started to hear reports of wind shear on the tower frequency. There may have also been a wind shear advisory on the ATIS. The Captain decided to change the takeoff thrust setting and use TOGA. I asked if he would also like to use Flaps 2. He said yes and I requested Flaps 2 takeoff data from the ACARS. While I was doing this the Captain began reprogramming the Perf page by entering 2 in the Flap setting. When we received the Takeoff data; we had a long discussion about what speeds he wanted for takeoff. He decided to use the Max thrust V-speeds for V1 and Vr and a speed of 142 for rotate. This speed was well below the 154 Vr maximum listed on the data; but he chose it because it matched the 10 knot tailwind Vr for a reduced takeoff (I guess this is his technique). I programmed the speeds into the Perf page and shortly thereafter we departed 4L; rotating at 142 knots. At 800 feet AFE; upon power reduction; the Captain noticed and stated that the flaps were still at position 1 and that we had never set Flaps 2. We discussed what had occurred and compared the speeds we had used with the Flaps 1 data. It appeared that we rotated 4 knots below the rotate speed for Flaps 1 reduced; but I didn't think to compare it to the Vr speed on the TOGA thrust line for the Flaps 1 data.The error was that we did not comply with the flight manual and repeat the Before Takeoff Checklist after repositioning a flight control. Other contributing factors were my flow for setting the new Flap position on the Perf page followed by moving the flap lever to the proper position was interrupted by the Captain selecting position 2 on the Perf page; the extensive discussion on V-speeds; and the first time flying together with this out of domicile Captain.

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.