B747 Undifferentiated or Other Model
Flight Crew Last 90 Days 240; Flight Crew Total 23000; Flight Crew Type 1000
Human-Machine Interface
Deviation / Discrepancy - Procedural Weight And Balance
Flight Crew Overcame Equipment Problem
Human Factors; Procedure; Aircraft
We were instructed to block rows 60 and 61 for an aft CG condition. The published CG was 24.8% and the Stabilizer trim setting was 5.8 Units. At VR -171 KTS I attempted to rotate normally but; the airplane did not rotate. I continued the back movement of the control column and had to exert at least TWICE the back pressure I normally would and the aft movement of the yoke was approaching the aft limit when the nose wheel finally left the runway. As soon as we were airborne I began to apply nose-up trim in one second deliberate applications. It took THREE one second applications until the yoke returned to a normal displacement from neutral. The actual CG of the airplane was obviously much further forward than what we were told in writing by load planning. Also; I could tell the airplane was much heavier than we were told (Leaving the gate 866.0). The initial pitch attitude was only about 13 degrees vs. 15+ degrees for an aircraft at this weight; and when I began to accelerate at 3;000 FT AGL for flap retraction and reduced the pitch attitude to 8 degrees like I normally do it resulted in a descent rate of about 300 FPM vs. a climb of about 500 FPM. The aircraft weight was higher than we were told and the CG was much further forward than we were told. Also; we noticed after departure that the Stabilizer tank was loaded with fuel and the Center Tank was NOT at capacity per the normal fuel loading procedure described the 747 CBT training materials.
Advised by load planners to block off aft rows of seats due to an allegedly aft CG and given a takeoff trim setting commensurate with that CG location the pilot flying of a B747 was unable to rotate at VR with normal elevator input and was required to apply several seconds of nose up pitch trim in order to rotate and lift off.