Narrative:

Incorrect takeoff weight entered into ACARS takeoff performance module.maintenance was called out to replace the performance computer. Maintenance MEL'd the performance computer and flight pushed late due to required procedures. Dispatch and I agreed I would retrieve takeoff data via ACARS. During briefings I verified with first officer (first officer) we would use the ACARS for in place of the performance computer takeoff data. He entered the ATIS information into the ACARS takeoff performance page and we waited for the loadsheet. The load sheet arrived and weights were entered and takeoff data reviewed; speeds set etc. I then called for the before start check. I verified zero fuel weight (ZFW) checked; and takeoff weight crosschecked with the FMC performance page and the ACARS takeoff performance page. Acceleration seemed normal; rotation was noticeably sluggish and I stopped the rotation and let the aircraft fly off which it did at 150 KIAS. I delayed the gear up call; told the first officer to apply climb thrust as we were in climb two. This occurred following retracting gear. The remainder of departure was uneventful. Upon reviewing the ACARS performance module it became apparent the ZFW was entered into the takeoff weight (tow). All of our data was incorrect.first; neither of us recognized the ZFW was entered into tow on the ACARS page. Also neither of us had used this procedure before and we haven't discussed it in ground school to my recollection. Third; the habit pattern is to enter ZFW and tow in the performance computer. Only tow gets entered into the ACARS performance page. Finally; I verified the data was correct because I saw 117.1 which was our ZFW and verbalized it. When the first officer read tow on the checklist I saw 150.1 on the FMC/CDU performance page and verbalized it but did not catch the incorrect entry in the ACARS performance page. This error has the potential to be catastrophic and needs some exposure in training and operations.

Related reports:

Google
 

Original NASA ASRS Text

Title: A B737-700 Flight Crew reports departing with an inoperative performance computer by entering weights from the ACARS into the CDU. The First Officer enters the zero fuel weight into the box that requires takeoff weight; resulting in sluggish takeoff performance. Thrust is increased after the gear is retracted.

Narrative: Incorrect takeoff weight entered into ACARS Takeoff Performance module.Maintenance was called out to replace the performance computer. Maintenance MEL'd the performance computer and flight pushed late due to required procedures. Dispatch and I agreed I would retrieve takeoff data via ACARS. During briefings I verified with First Officer (FO) we would use the ACARS for in place of the performance computer takeoff data. He entered the ATIS information into the ACARS Takeoff Performance page and we waited for the loadsheet. The load sheet arrived and weights were entered and takeoff data reviewed; speeds set etc. I then called for the Before Start Check. I verified Zero fuel Weight (ZFW) checked; and takeoff weight crosschecked with the FMC Performance page and the ACARS Takeoff Performance page. Acceleration seemed normal; rotation was noticeably sluggish and I stopped the rotation and let the aircraft fly off which it did at 150 KIAS. I delayed the gear up call; told the FO to apply climb thrust as we were in climb two. This occurred following retracting gear. The remainder of departure was uneventful. Upon reviewing the ACARS performance module it became apparent the ZFW was entered into the Takeoff Weight (TOW). All of our data was incorrect.First; neither of us recognized the ZFW was entered into TOW on the ACARS page. Also neither of us had used this procedure before and we haven't discussed it in ground school to my recollection. Third; the habit pattern is to enter ZFW and TOW in the performance computer. Only TOW gets entered into the ACARS Performance page. Finally; I verified the data was correct because I saw 117.1 which was our ZFW and verbalized it. When the FO read TOW on the checklist I saw 150.1 on the FMC/CDU Performance page and verbalized it but did not catch the incorrect entry in the ACARS Performance page. This error has the potential to be catastrophic and needs some exposure in training and operations.

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.