Narrative:

Inbound den-oak flight xx arrived late at oak for a scheduled short turn time. I advised the captain I would go do the aircraft walk-around while he prepared the cockpit for our next leg. As we taxied out to the runway everything was proceeding as normal. We were cleared for takeoff while taxiing, so we were going to take it on the roll. I went to update the FMC and noticed a prompt to check present position. I went to the present position page and saw that the airport and the gate coordinates were not entered in the computer. I advised the captain and he said, 'you'd better hurry up and put it in.' at this point I advised him it would take 10 mins and we needed to be parked at the gate. He said it would only take 30 seconds and reached up and went from navigation to align. At this point both the ehsi and eadi screens went to their normal alignment pictures (no information). It was my turn to fly and I told the captain my screens were not displaying any flight information. He said to 'go,' and they would come during the roll. I proceeded with the takeoff at 100 KTS. I still had no picture and had to use the standby attitude indicator (sai) to rotated and climb out. During the climb the captain put the IRS into the attitude mode. We received partial information on the screens. I then suggested that we return to oak as it was cavu and lax was forecasting possible clouds and fog. We returned to oak and made an uneventful landing. We taxied in, put on fuel, called dispatch, maintenance and realigned the IRS system. The mechanics watched as it realigned normally. We were cleared to go and had an uneventful trip to lax.

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Original NASA ASRS Text

Title: ACR MLG INITIATED TKOF WITH IMPROPERLY ALIGNED IRS AND ERRONEOUS FLT INSTRUMENT INDICATIONS.

Narrative: INBND DEN-OAK FLT XX ARRIVED LATE AT OAK FOR A SCHEDULED SHORT TURN TIME. I ADVISED THE CAPT I WOULD GO DO THE ACFT WALK-AROUND WHILE HE PREPARED THE COCKPIT FOR OUR NEXT LEG. AS WE TAXIED OUT TO THE RWY EVERYTHING WAS PROCEEDING AS NORMAL. WE WERE CLRED FOR TKOF WHILE TAXIING, SO WE WERE GOING TO TAKE IT ON THE ROLL. I WENT TO UPDATE THE FMC AND NOTICED A PROMPT TO CHK PRESENT POS. I WENT TO THE PRESENT POS PAGE AND SAW THAT THE ARPT AND THE GATE COORDINATES WERE NOT ENTERED IN THE COMPUTER. I ADVISED THE CAPT AND HE SAID, 'YOU'D BETTER HURRY UP AND PUT IT IN.' AT THIS POINT I ADVISED HIM IT WOULD TAKE 10 MINS AND WE NEEDED TO BE PARKED AT THE GATE. HE SAID IT WOULD ONLY TAKE 30 SECS AND REACHED UP AND WENT FROM NAV TO ALIGN. AT THIS POINT BOTH THE EHSI AND EADI SCREENS WENT TO THEIR NORMAL ALIGNMENT PICTURES (NO INFO). IT WAS MY TURN TO FLY AND I TOLD THE CAPT MY SCREENS WERE NOT DISPLAYING ANY FLT INFO. HE SAID TO 'GO,' AND THEY WOULD COME DURING THE ROLL. I PROCEEDED WITH THE TKOF AT 100 KTS. I STILL HAD NO PICTURE AND HAD TO USE THE STANDBY ATTITUDE INDICATOR (SAI) TO ROTATED AND CLB OUT. DURING THE CLB THE CAPT PUT THE IRS INTO THE ATTITUDE MODE. WE RECEIVED PARTIAL INFO ON THE SCREENS. I THEN SUGGESTED THAT WE RETURN TO OAK AS IT WAS CAVU AND LAX WAS FORECASTING POSSIBLE CLOUDS AND FOG. WE RETURNED TO OAK AND MADE AN UNEVENTFUL LNDG. WE TAXIED IN, PUT ON FUEL, CALLED DISPATCH, MAINT AND REALIGNED THE IRS SYS. THE MECHS WATCHED AS IT REALIGNED NORMALLY. WE WERE CLRED TO GO AND HAD AN UNEVENTFUL TRIP TO LAX.

Data retrieved from NASA's ASRS site as of July 2007 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.