SF340 SCRAPES TAIL ON LNDG AT BTR.

Narrative

WE WERE CLRED FOR A VISUAL APCH TO RWY 22R AT BTR. CONDITIONS WERE NIGHT; CLR; WIND 24 DEGS 11 KTS; SMOOTH; AND DRY RWY. MY FO WAS THE PF. SHE FLEW A NORMAL APCH WITH NO DIFFICULTIES. ACFT WT WAS 900 LBS BELOW MAX LNDG WT; HOWEVER THE CTR OF GRAVITY WAS AT THE ABSOLUTE MAX AFT LEGAL LIMIT. UPON TOUCHDOWN AT APPROX VREF -5 KTS THE FO COULD NOT GET THE NOSE TO COME DOWN. WE PROCEEDED DOWN THE RWY IN A PITCHED UP ATTITUDE FOR APPROX 2 SECONDS AT WHICH TIME I ADDED MY ASSISTANCE IN PROVIDING FULL PITCH DOWN CTL PRESSURE ON THE YOKE. AS THE ACFT SLOWED; THE NOSE PITCHED FURTHER AND FURTHER UP. AS SOON AS I FELT THE NOSE MOVING UP I APPLIED A SUBSTANTIAL AMOUNT OF PWR TO BRING THE NOSE DOWN AND TOOK FULL CTL OF THE ACFT. ONCE PWR WAS APPLIED; THE NOSE CAME DOWN TO THE RWY AND WE WERE ABLE TO HOLD IT THERE THROUGHOUT THE LNDG ROLL. HOWEVER; PRIOR TO ADDING PWR TO BRING THE NOSE DOWN; THE REAR OF THE FUSELAGE CONTACTED THE RWY. ON POSTFLT WE DISCOVERED MINIMAL DAMAGE TO THE ACFT; CONSISTING OF SCRAPED PAINT; BENT TAIL STAND INSERT AND DAMAGED REAR AERODYNAMIC STRAKES. CONTRIBUTING FACTORS AND REASONS: 1) POSSIBLE CARGO SHIFT INFLT CHANGING THE CTR OF GRAVITY; AND 2) LACK OF ACTUAL WT INFO. MY COMPANY USES AVERAGE WTS FOR BOTH PAX AND CARGO/LUGGAGE. I BELIEVE THAT IN AN ACFT THE SIZE OF THE SAAB; AVERAGE WTS OFTEN RESULT IN THE ACFT EXCEEDING MAX WT LIMITS AND CTR OF GRAVITY LIMITATIONS; ALTHOUGH ON PAPER THE ACFT IS LEGAL.