AN ACR B737-400 FO SCRAPED THE BELLY ON LNDG. ACFT DAMAGE FUSELAGE SKIN; 2 ANTENNAS. ERROR ADMITTED.

Narrative

13 YR EMPLOYEE -- CAPT/FLT INSTRUCTOR/IOE INSTRUCTOR. 3 MONTH EMPLOYEE -- FO ON IOE TRAINING; 27 HRS EXPERIENCE IN TYPE AND WITH COMPANY. I WAS FLYING A VISUAL APCH TO RWY 34R AT SEATAC. THE APCH WAS NORMAL; ON AIRSPD AND ON ALT. DURING THE FLARE; PWR WAS PULLED OFF AND THE ACFT BALLOONED A LITTLE BIT. THE AIRSPD GOT A LITTLE SLOW; ABOUT 4-5 KTS BELOW VREF. THE LNDG THAT ENSUED WAS MODERATELY FIRM BUT NOT ABNORMALLY HARD. AFTER THE INITIAL LNDG; THE ACFT BOUNCED INTO THE AIR. THE CAPT THEN PUT HIS HANDS ON THE CTLS AND TOLD ME TO 'CHK.' DURING OUR 17 HRS OF PREVIOUS TRAINING 'CHK' HAD ALWAYS MEANT TO PULL BACK ON THE YOKE A LITTLE BIT. I PULLED BACK ON THE YOKE SLIGHTLY AND THE ACFT SETTLED TO THE GND. DURING THE POSTFLT; DAMAGE TO THE UNDERSIDE OF ACFT WAS NOTICED. METAL WAS WORN ON THE UNDERSIDE; 2 ANTENNAS WERE DESTROYED. THE DAMAGED AREA WAS BTWN THE AREA BEHIND THE FLAPS UP TO THE DRAIN MAST. THE TAIL SKID WAS NOT DAMAGED. THE ACFT WAS AT A HVY LNDG WT. FLT ATTENDANTS AND PAX DID NOT SEEM TO NOTICE THAT THE ACFT HAD BEEN DAMAGED.