Flight Crew Last 90 Days 141; Flight Crew Type 15000
Communication Breakdown
Deviation / Discrepancy - Procedural Weight And Balance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew FLC Overrode Automation
Company Policy; Human Factors
I would like to share my concern about our current -800 loading procedures and how they result in nose heavy flight characteristics during takeoff. I was dispatched in [this] aircraft. The Agent input all 120 Passengers into Zone 1 as per our current procedures. We had 4;000 pounds of freight in the forward hold. The load sheet predicted trim 5.6; but the performance computer generated 6.1. The aircraft required an unusual amount of back pressure during takeoff. I began nose-up trim shortly after liftoff requiring a setting of about 7.5 to achieve acceptable performance. I had the Flight Attendants acquire a zone count during the flight. During ground operations had the Agent rerun the loading with the zone count (49/46/25). The predicted trim was 6.7. I do not know what the performance computer would have generated; but given that it generally adds about .3-.5 units; it may have given me 7.0-7.2 - much closer to normal aircraft performance. Note: Landing trip was 10.5. We departed with 84 Passengers using a zone count of 36/33/15 computation and 1;200 pounds of cargo/bags. The loadsheet predicted a trim of 6.0 and the [flight computer] gave us 6.3. The flight performance was normal during takeoff. The concern is that the policy of placing the Passenger load into a single Zone 1 on the loading schedule is generating routinely nose-heavy performance. Not only are we decreasing the fuel efficiency of the aircraft; but we are not compensating with a realistic trim setting. Please review the software assumptions of this operation.
B737-800 Captain experienced conflicting loading procedures and calculations of weight and balance and takeoff performance data. Captain reported that the load planning assumptions in the weight and balance computer and the station lading procedures results in nose-heavy flight characteristics on takeoff and recommends a review of those assumptions and procedures.