Narrative:

The event began as a scheduled aircraft swap with numerous other connecting flight delays. When the aircraft was ready for departure; it was determined that 28 connecting passengers would miss our already late flight. At that time; the agents realized that the flight wasn't properly loaded for departure without those 28 passengers; so ramp was directed to redistribute our bags to accommodate cg considerations since this was an -800 series aircraft. By the time that had been completed and paperwork was complete; it was determined by the agents that we would then wait for the connecting passengers from two other inbound flights after all. Once those passengers and bags arrived (27 additional passengers with baggage); a new load closeout sheet was sent to the flightdeck and the performance was calculated. We set stabilizer trim as calculated and proceeded to start engines; taxi; and takeoff. At the rotate call; I applied aft stick pressure to the yoke and noted that forces were considerably higher than anticipated; especially as I neared the aft stop. At nearly full aft stick travel of the yoke I was about to call for emergency thrust when nose strut extension finally occurred. I estimate that several hundred feet of additional takeoff roll was required to unstick from the runway. Aircraft loading and cg was clearly not what the paperwork reflected as the stick forces and elevator displacement were unacceptably high and the rotation significantly delayed as a result. I doubt the aircraft would have been flyable if an engine failure had occurred after V1 in this case. We may want to consider return to the [original] loading schedule on -800 aircraft to more clearly articulate to all parties how the aircraft is actually loaded. Additional oversight should be instituted when multiple changes to passengers; baggage; or cargo configuration have been performed on -800 series aircraft. Stabilizer trim setting incorrect due to aircraft weight and balance issue.

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Original NASA ASRS Text

Title: B737-800 flight crew describe last minute changes to the passenger count and bag loading that results in an inaccurate load sheet and an incorrect takeoff trim setting.

Narrative: The event began as a scheduled aircraft swap with numerous other connecting flight delays. When the aircraft was ready for departure; it was determined that 28 connecting passengers would miss our already late flight. At that time; the Agents realized that the flight wasn't properly loaded for departure without those 28 passengers; so Ramp was directed to redistribute our bags to accommodate CG considerations since this was an -800 series aircraft. By the time that had been completed and paperwork was complete; it was determined by the Agents that we would then wait for the connecting passengers from two other inbound flights after all. Once those passengers and bags arrived (27 additional passengers with baggage); a new load closeout sheet was sent to the flightdeck and the performance was calculated. We set stabilizer trim as calculated and proceeded to start engines; taxi; and takeoff. At the rotate call; I applied aft stick pressure to the yoke and noted that forces were considerably higher than anticipated; especially as I neared the aft stop. At nearly full aft stick travel of the yoke I was about to call for emergency thrust when nose strut extension finally occurred. I estimate that several hundred feet of additional takeoff roll was required to unstick from the runway. Aircraft loading and CG was clearly not what the paperwork reflected as the stick forces and elevator displacement were unacceptably high and the rotation significantly delayed as a result. I doubt the aircraft would have been flyable if an engine failure had occurred after V1 in this case. We may want to consider return to the [original] loading schedule on -800 aircraft to more clearly articulate to all parties how the aircraft is actually loaded. Additional oversight should be instituted when multiple changes to passengers; baggage; or cargo configuration have been performed on -800 series aircraft. Stabilizer trim setting incorrect due to aircraft weight and balance issue.

Data retrieved from NASA's ASRS site as of July 2013 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.