FO FLYING SAAB 340 (SF34L) EXPERIENCED DIFFICULTY DURING LNDG FLARE. THE NOSE PITCHED UP UNCOMMANDED CAUSING PWR TO BE ADDED AND ELEVATOR PITCH DOWN PRESSURE TO MAKE NORMAL LNDG. THE CAUSE WAS FOUND TO BE HIGHER THAN NORMAL BAGGAGE WT IN THE AFT BAGGAGE COMPARTMENT WHICH WAS NOT REFLECTED ON THE DEP WT AND BAL. THE AFT CTR OF GRAVITY LIMITS WERE EXCEEDED.

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ON A ROUTINE FLT FROM LAX TO SAN; WE; THE FLC; WERE GIVEN OUR WTS FOR THE CARGO COMPARTMENT BY THE GND CREW. WITH THE WTS PROVIDED; WE CALCULATED OUR WT AND BAL FOR THE SAAB 340 AND DETERMINED THE CTR OF GRAVITY AND ACFT WTS TO BE WITHIN LIMITATIONS. THE CTR OF GRAVITY WAS NEAR THE AFT CTR OF GRAVITY LIMIT AND INSIDE THE ENVELOPE; SO DURING TKOF IT LIFTED OFF WITH MINIMAL INITIAL BACK PRESSURE ON THE YOKE. ENRTE AND WITH AUTOPLT ON; ALL WAS NORMAL. DSCNT AND APCH OCCURRED WITH NORMAL SENSATIONS FROM THE AUTOPLT AND MANUAL CTL. IT WASN'T UNTIL REDUCING PWR DURING THE LNDG FLARE THAT THE ACFT STARTED AN ABNORMAL ATTITUDE. APPROX 10 FT ABOVE THE RWY 27 APCH TOUCHDOWN ZONE THE ACFT WAS IN GND EFFECT AND THE NOSE CONTINUED TO RISE WITHOUT USING ELEVATOR BACK PRESSURE. THE AIRSPD BEGAN TO DECREASE BELOW VREF AND THE ACFT WOULD NOT SINK ANY FURTHER AS THE AFT CTR OF GRAVITY CONDITION PREVAILED. THE PNF (CAPT) CALLED OUT AIRSPD VREF -10 AND BEGAN TO SOUND UNEASY WHY THE ACFT WAS STILL IN THE AIR (APPROX 5-10 FT AGL). I HAD TO INCREASE PWR; USE FORWARD ELEVATOR PRESSURE AND NOSE DOWN TRIM; TO LAND THE ACFT. A SAFE LNDG OCCURRED WITH ABNORMAL INPUTS TO CTL THE ACFT. AFTER LNDG; THE CAPT INQUIRED WHAT WAS GOING ON WITH THE ACFT. MY REPLY WAS TO INFORM HIM THAT SOMETHING STRANGE WAS GOING ON WITH THE ACFT HANDLING. HE ADVISED THE STATION THAT ALL BAGGAGE IN THE CARGO HOLDS WERE TO BE WEIGHED. THE RESULTS OF WEIGHING THE BAGGAGE PROVED TO BE THE FACTOR THAT CAUSED THE ABNORMAL FLARE DURING LNDG. THE WTS WERE VERY EXCESSIVE; OVER 1000 LBS IN ERROR AND COMPLETELY CONTRADICTORY TO THE INFO PROVIDED TO US AT PREFLT AND DURING OUR LOADING CALCULATIONS. THIS ERROR BY THE GND CREW RESULTED IN AN INSTABILITY AND OVERWT SIT BECAUSE THE SYS DOES NOT ACTUALLY WEIGH EACH BAG/SUITCASE; BUT A COUNT IS TAKEN OF THE NUMBER OF BAGS AND MULTIPLIED BY A WT FACTOR. THIS PROVED TO BE DANGEROUS SINCE MANY OF THE BAGS WERE A LOT HEAVIER THAN AVERAGE. ALSO; THEIR COUNT WAS INACCURATE WHICH ALSO CAUSED ERRONEOUS INFO TO BE UTILIZED. THE COMPANY IS TAKING CORRECTIVE ACTION TO RECTIFY THE LOADING PROCS FOR OUR OP. NO ACFT DAMAGE WAS OBSERVED AND LNDG OCCURRED SMOOTHLY.