Narrative:

En route to phl from fll at FL240, clearance was to cross 30 NM south of sea isle (sie) at 15000 ft. I entered that point into the FMC, set the altitude alerter with concurrence of the first officer, and started a 1000 FPM descent using 'vertical speed.' then referencing the 'descent page' and noting a required rate of 1250 FPM, I set the vertical speed to 1300 FPM to make the restr. We were both set up in navigation mode, with no sie raw data displayed. The lead flight attendant then called the first officer with a cabin discrepancy needing maintenance upon arrival in phl, while I monitored ATC. I then got out the logbook to record the item. A min or so later, ATC asked if we had been given a crossing restr. Upon checking the FMC, we had already passed the crossing point and were about 25 NM south of sie passing FL190. I then realized I had inadvertently inserted the 15000 ft at sie, rather than at the 30 south point I had created. This occurrence points out the need for both pilots to xchk and confirm all FMC entries, as well as the need for a raw data backup for all crossing restrs (especially important for non EFIS equipped aircraft such as ours, where the 'big picture' is not so readily apparent). During distrs from the cabin, it is imperative that 1 pilot continue to concentrate solely on navigating the aircraft.

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Original NASA ASRS Text

Title: ACFT MISSES XING ALT BY 4000 FT.

Narrative: ENRTE TO PHL FROM FLL AT FL240, CLRNC WAS TO CROSS 30 NM S OF SEA ISLE (SIE) AT 15000 FT. I ENTERED THAT POINT INTO THE FMC, SET THE ALT ALERTER WITH CONCURRENCE OF THE FO, AND STARTED A 1000 FPM DSCNT USING 'VERT SPD.' THEN REFING THE 'DSCNT PAGE' AND NOTING A REQUIRED RATE OF 1250 FPM, I SET THE VERT SPD TO 1300 FPM TO MAKE THE RESTR. WE WERE BOTH SET UP IN NAV MODE, WITH NO SIE RAW DATA DISPLAYED. THE LEAD FLT ATTENDANT THEN CALLED THE FO WITH A CABIN DISCREPANCY NEEDING MAINT UPON ARR IN PHL, WHILE I MONITORED ATC. I THEN GOT OUT THE LOGBOOK TO RECORD THE ITEM. A MIN OR SO LATER, ATC ASKED IF WE HAD BEEN GIVEN A XING RESTR. UPON CHKING THE FMC, WE HAD ALREADY PASSED THE XING POINT AND WERE ABOUT 25 NM S OF SIE PASSING FL190. I THEN REALIZED I HAD INADVERTENTLY INSERTED THE 15000 FT AT SIE, RATHER THAN AT THE 30 S POINT I HAD CREATED. THIS OCCURRENCE POINTS OUT THE NEED FOR BOTH PLTS TO XCHK AND CONFIRM ALL FMC ENTRIES, AS WELL AS THE NEED FOR A RAW DATA BACKUP FOR ALL XING RESTRS (ESPECIALLY IMPORTANT FOR NON EFIS EQUIPPED ACFT SUCH AS OURS, WHERE THE 'BIG PICTURE' IS NOT SO READILY APPARENT). DURING DISTRS FROM THE CABIN, IT IS IMPERATIVE THAT 1 PLT CONTINUE TO CONCENTRATE SOLELY ON NAVING THE ACFT.

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.