ERRONEOUS TKOF SPDS; TAIL STRIKE.

Narrative

AN ACFT MECH ARRIVED ON THE FLT DECK WITH ACFT LOGBOOK AND TO INSTALL MEL PLACARD IN #3 THRUST REVERSER. UPON COMPLETION OF THIS; THE MECH REMAINED ON BOARD TO DISCUSS THE LOGBOOK ENTRY. THE LOAD MASTER ARRIVED WITH THE LOAD PLAN AND THE CAPT ANNOUNCED 'TAPES UP' TO WHICH ALL CONVERSATION STOPPED. CAPT READ OFF THE '0' FUEL WT; WHICH THE FE COPIES DOWN ON HIS FORM; FOLLOWED BY THE TKOF WT. I WROTE DOWN ON MY WT DATA RECORD AS 208314 LBS BECAUSE THAT'S WHAT I HEARD BUT THE CAPT SAID AND THE FE WROTE DOWN A TKOF WT OF 287314 LBS WHICH REFLECTED THE CORRECT TKOF WT. NOTE: THIS IS THE FIRST AREA WHERE THE PROB OCCURRED. OUR COMPANY PROCS REQUIRE THE FO AND FE TO INDIVIDUALLY CONSULT OUR ACFT PERFORMANCE MANUALS/CHARTS FOR THE V1; VR; V2; V2+25; 1.25 VS/O 1.5 AND STABILIZER SETTING. IT'S OUR PROC FOR THE FO TO ANNOUNCE THE WT AND COLUMNS THAT WILL BE USED TO COMPUTE THIS INFO. I ANNOUNCED BASED UPON A 208314 WT; THAT WE WOULD USE 210000 LBS: 1 KT; COLUMNS 2 AND 6 TO WHICH THE FE SAID 'OK.' THIS IS THE FIRST PLACE WHERE THE FE SHOULD HAVE CAUGHT THE ERROR BUT DID NOT. AFTER COMPLETING MY NUMBERS; I CALLED READY FOR XCHK AND THE FE SAID; GO AHEAD. BOTH THE FE AND MYSELF HAD THE EXACT SAME AIRSPD NUMBERS FOR 210000 LBS. THE ENG START CHKLIST AND AFTER START CHKLIST WERE CALLED FOR AND COMPLETED BY THE CREW. AFTER PUSHBACK; I CALLED FLT CTL ON #2 VHF AND GAVE THEM OUR BLOCKOUT TIME AND THEN CHANGED FREQ TO DAYTON APCH FOR OUR IFR RELEASE AND I LEFT THE VOLUME ON #2 UP SLIGHTLY. DURING OUR DAY OPS WE DID NOT HAVE OUR PVT CTL TWR/GND IN OP; SO WE ARE REQUIRED TO MAKE A BLANKET CALL ON OUR CTAF FREQ THAT WE ARE TAXIING FOR DEP; WHICH I DID. THE CAPT CALLED FOR FLAPS 18 DEGS AND TAXI CHKLIST. WHEN WE GOT DOWN TO THE TKOF BRIEFING ON THE TAXI CHKLIST; THE CAPT ANNOUNCED TKOF BRIEFING THAT BEGAN WITH REDUCED PWR; FLAPS 18 DEGS TKOF AT XXXX. AT THAT MOMENT WHEN HE STARTED TO SAY THE TKOF WT; I WAS DISTRACTED BY THE #2 VHF RADIO; BECAUSE ANOTHER OF OUR COMPANY ACFT HAD CALLED DAYTON AND ASKED FOR RELEASE OFF OF OUR ARPT. THE REASON THIS WAS SO DISTRACTING IS BECAUSE I DID NOT HEAR OR SEE ANY OTHER ACFT AROUND US. SO I BEGAN TO LOOK AROUND WHICH IS WHY I DID NOT HEAR THE CAPT SAY THAT THIS WOULD BE A 288000 LB TKOF. AFTER SEEING NO OTHER ACFT IN THE AREA; I AGAIN TURNED MY ATTN TO THE CAPT WHO WAS ABOUT TO BRIEF THE SPDS OFF OF THE TKOF CARD. HE READ THE SPDS OUT AND THEN QUESTIONED ME THAT THOSE SPDS DID NOT LOOK 'RIGHT.' I IMMEDIATELY PICKED UP THE PERFORMANCE MANUAL AND CONFIRMED THE SPDS. I THEN TOLD THE CAPT THAT ANOTHER ACFT HAD CALLED FOR RELEASE; TO WHICH HE REPLIED THAT THEY MUST BE BEHIND US AND GOING TO TKOF FROM AN INTXN RATHER THAN FULL LENGTH AS WE WERE. WE THEN COMPLETED THE TAXI CHKLIST; AS WE TURNED THE CORNER THE CAPT WAS CORRECT AS A DC-9 WAS DEPARTING FROM THE INTXN BEHIND US. WE GOT OUR RELEASE; MADE OUR CALLS ON THE CTAF; COMPLETED THE BEFORE TKOF CHKLIST AND STARTED OUR TKOF. I CALLED 80 KTS AND THE CAPT REPLIED 'CHKED.' I CALLED V1 AT 105 KTS; VR AT 118 KTS; ROTATE AT 136 KTS. THE ACFT BECAME AIRBORNE THEN SETTLED BACK ONTO THE RWY. THE CAPT CALLED FOR MAX PWR. THE ACFT ACCELERATED AND BECAME AIRBORNE. WE REQUESTED AND RECEIVED DELAYED VECTORS FROM DAY DEP CTL TO SORT OUT OUR PROB. WE LEFT THE GEAR AND FLAPS EXTENDED; ACCOMPLISHED THE QUICK RETURN CHKLIST AND REQUESTED A FLY-BY FOR MAINT TO CHK OUR GEAR AND FLAPS. WE ACCOMPLISHED THE FLY-BY WITH MAINT INDICATING THAT THEY OBSERVED NO PROBS. WE RECYCLED THE LNDG GEAR AND THE FLAPS WITH NO PROBS. THE CAPT MADE THE DECISION AND WE CONCURRED THAT WE SHOULD CONTINUE TO LONG BEACH; CA. AFTER LEVELOFF WE BEGAN TO DISCUSS WHAT HAD OCCURRED AND WHAT MIGHT HAVE CAUSED OUR PROB. IT WAS THEN THAT I JUST HAPPENED TO LOOK AT THE LOAD PLAN AND DISCOVERED THAT OUR ACTUAL TKOF WT WAS 287314 AND THAT I HAD MADE AN 80000 LB ERROR. OUR COMPANY PROCS AND CHKLISTS WERE ADHERED TO. HOWEVER; I FEEL THAT A CONTRIBUTING FACTOR WAS THAT THE MECH; THAT WAS ON THE FLT DECK; BEGAN TO SPEAK TO THE FEWHEN I TURNED TO HIM AND TOLD HIM 210; 1 KT; COLUMNS 2 AND 6. THE FE INDICATED; AND ALL HIS PAPER WORK TO INCLUDE THE TKOF CARD INDICATED; 288000 LBS. HE ALSO INDICATED THAT HE HEARD ME SAY 210000 BUT IT DIDN'T REGISTER. THE SECOND TIME THAT THE ERROR SHOULD HAVE BEEN CAUGHT WAS DURING THE CAPT'S TKOF BRIEFING. BUT I WAS DISTRACTED BY A RADIO CALL. OUR PVT ARPT OPERATES AS AN UNCTLED ARPT DURING DAY OPS. WE ARE REQUIRED TO CALL DAY DEP FOR RELEASE BUT WE MUST PROVIDE OUR OWN LCL CTL WITH OTHER ACFT THAT MIGHT BE IN THE PATTERN. IT HAS BEEN MY PAST EXPERIENCE THAT IN ORDER TO KEEP SITUATIONAL AWARENESS; YOU MUST MONITOR BOTH VHF #1 AND #2. THE THIRD TIME THAT THE ERROR COULD HAVE BEEN CAUGHT WAS WHEN THE CAPT QUESTIONED ME ABOUT THE SPDS NOT LOOKING RIGHT. IF EITHER ONE OF US HAD MENTIONED THE WT; THE ERROR WOULD HAVE BEEN CAUGHT BUT IT WASN'T. SO HERE IS A CLASSIC CASE OF COCKPIT RESOURCE MGMNT BREAKDOWN. THE ACFT'S TAIL SKID WAS THE ONLY AREA THAT HAD TO BE REPLACED.