Narrative:

Our opc was not charging in the cradle; so when we got our load sheet; the computer indicated only 1 bar of battery power left. It then seemed to 'lock up;' apparently due to the low battery. We had a wheels up time 6-8 mins later. I rationalized that since we could charge the battery quickly; our opc really was not inoperative and; therefore; did not need to be MEL'ed. I called dispatch through operations and got our takeoff data so we could still make our takeoff window. Dispatch calculated our V1; vr; and V2 of 113; 113; and 119. Taxiing out; I remarked to my first officer that those numbers seemed a little low for a 140000 pound takeoff; but then I remembered I had felt that way before on the -700 with winglets and the numbers had always been good. Takeoff roll was normal; and I began rotation at 113 KTS. When the aircraft got 10 degrees aircraft nose up; I noticed that it did not feel like a normal takeoff; ie; getting light on the main gear and about to fly. I remembered that in the -300 a pitch attitude of 11 degree annunciation could result in a tail strike. My guess is that number is probably a little higher in the -700; but I decided to stop the rotation at 10 degrees annunciation; as we still had probably 3000-4000 ft of runway. We rolled down the runway at 10 degrees annunciation for another 1000-1500 ft until the aircraft lifted off; at which time I continued the rotation to 15 degrees annunciation. I retracted flaps on schedule and the rest of the takeoff was uneventful. I was skeptical of our takeoff data; so en route we fiddled with the opc and got a good charge. We then computed our takeoff speeds of V1; vr; and V2 of 125; 135; and 139. Yikes! Seems I rotated about 22 KTS early! I have obtained data over the radio with dispatch many times. Obviously this time we had some sort of communication problem; made worse by my 'hurry up we gotta flow time.' I used to use a quick check to get a ballpark figure in the -300. Seems I dropped that by the wayside somewhere. It certainly would have been a welcome catch today. Zero fuel weight +25 = V2 give or take a few? The rush to make our takeoff time was incredibly myopic in hindsight. Next time I have doubts or something doesn't feel right; I'll try and slow down and doublechk.

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Original NASA ASRS Text

Title: B737-700 RECEIVED INACCURATE V-SPDS FROM DISPATCH AFTER THE ACFT'S PORTABLE PERFORMANCE COMPUTER FAILED. INACCURATE SPDS CAUSED AN EARLY ROTATION TKOF.

Narrative: OUR OPC WAS NOT CHARGING IN THE CRADLE; SO WHEN WE GOT OUR LOAD SHEET; THE COMPUTER INDICATED ONLY 1 BAR OF BATTERY PWR LEFT. IT THEN SEEMED TO 'LOCK UP;' APPARENTLY DUE TO THE LOW BATTERY. WE HAD A WHEELS UP TIME 6-8 MINS LATER. I RATIONALIZED THAT SINCE WE COULD CHARGE THE BATTERY QUICKLY; OUR OPC REALLY WAS NOT INOP AND; THEREFORE; DID NOT NEED TO BE MEL'ED. I CALLED DISPATCH THROUGH OPS AND GOT OUR TKOF DATA SO WE COULD STILL MAKE OUR TKOF WINDOW. DISPATCH CALCULATED OUR V1; VR; AND V2 OF 113; 113; AND 119. TAXIING OUT; I REMARKED TO MY FO THAT THOSE NUMBERS SEEMED A LITTLE LOW FOR A 140000 LB TKOF; BUT THEN I REMEMBERED I HAD FELT THAT WAY BEFORE ON THE -700 WITH WINGLETS AND THE NUMBERS HAD ALWAYS BEEN GOOD. TKOF ROLL WAS NORMAL; AND I BEGAN ROTATION AT 113 KTS. WHEN THE ACFT GOT 10 DEGS ACFT NOSE UP; I NOTICED THAT IT DID NOT FEEL LIKE A NORMAL TKOF; IE; GETTING LIGHT ON THE MAIN GEAR AND ABOUT TO FLY. I REMEMBERED THAT IN THE -300 A PITCH ATTITUDE OF 11 DEG ANNUNCIATION COULD RESULT IN A TAIL STRIKE. MY GUESS IS THAT NUMBER IS PROBABLY A LITTLE HIGHER IN THE -700; BUT I DECIDED TO STOP THE ROTATION AT 10 DEGS ANNUNCIATION; AS WE STILL HAD PROBABLY 3000-4000 FT OF RWY. WE ROLLED DOWN THE RWY AT 10 DEGS ANNUNCIATION FOR ANOTHER 1000-1500 FT UNTIL THE ACFT LIFTED OFF; AT WHICH TIME I CONTINUED THE ROTATION TO 15 DEGS ANNUNCIATION. I RETRACTED FLAPS ON SCHEDULE AND THE REST OF THE TKOF WAS UNEVENTFUL. I WAS SKEPTICAL OF OUR TKOF DATA; SO ENRTE WE FIDDLED WITH THE OPC AND GOT A GOOD CHARGE. WE THEN COMPUTED OUR TKOF SPDS OF V1; VR; AND V2 OF 125; 135; AND 139. YIKES! SEEMS I ROTATED ABOUT 22 KTS EARLY! I HAVE OBTAINED DATA OVER THE RADIO WITH DISPATCH MANY TIMES. OBVIOUSLY THIS TIME WE HAD SOME SORT OF COM PROB; MADE WORSE BY MY 'HURRY UP WE GOTTA FLOW TIME.' I USED TO USE A QUICK CHK TO GET A BALLPARK FIGURE IN THE -300. SEEMS I DROPPED THAT BY THE WAYSIDE SOMEWHERE. IT CERTAINLY WOULD HAVE BEEN A WELCOME CATCH TODAY. ZERO FUEL WT +25 = V2 GIVE OR TAKE A FEW? THE RUSH TO MAKE OUR TKOF TIME WAS INCREDIBLY MYOPIC IN HINDSIGHT. NEXT TIME I HAVE DOUBTS OR SOMETHING DOESN'T FEEL RIGHT; I'LL TRY AND SLOW DOWN AND DOUBLECHK.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.