Narrative:

Captain had gone to the back, and ATC had cleared us to descend to cross 55 mi north of beryl intersection at FL290. We were at FL330. I put FL290 in the FMC and the MCP. Somehow became distraction and did not push the execute button. A factor here was that the light switch was still in dim from the pre-dawn takeoff, and the execute light was not very visible. Anyway, the FMC never started down and I did not notice, until ATC asked if we were going to make the crossing restr. I went to level change at that time, but still did not make it down by the crossing fix. No further comments from ATC. About the time ATC was asking if we were going to make the restr, the captain called and came back up from the back. Factors contributing to this event were a failure to complete the altitude change task because of some distraction that I don't remember what it was, a dim execute light that might have reminded me to finish the task, and not having another pilot to catch my mistake. Supplemental information from acn 593879: while I was absent from the flight deck to use the restroom, a clearance had been issued to cross 50 NM northwest of drake (north of phx) at FL290. When I returned from the restroom, I had not been informed of the ATC issued crossing restr. As I strapped in and put my headset on, center requested that we start our descent immediately to comply with the clearance. As I looked at the navigation display, I noticed that the first officer had programmed a fix of drk/01 which turned out to be the crossing restr point. When ATC called to direct the immediately descent, the aircraft was passing the point for the crossing restr at FL330.

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Original NASA ASRS Text

Title: B737 FLT CREW FAILS TO COMPLY WITH ATC DIRECTED ALT XING RESTR INBOUND TO PHX.

Narrative: CAPT HAD GONE TO THE BACK, AND ATC HAD CLRED US TO DSND TO CROSS 55 MI N OF BERYL INTXN AT FL290. WE WERE AT FL330. I PUT FL290 IN THE FMC AND THE MCP. SOMEHOW BECAME DISTR AND DID NOT PUSH THE EXECUTE BUTTON. A FACTOR HERE WAS THAT THE LIGHT SWITCH WAS STILL IN DIM FROM THE PRE-DAWN TKOF, AND THE EXECUTE LIGHT WAS NOT VERY VISIBLE. ANYWAY, THE FMC NEVER STARTED DOWN AND I DID NOT NOTICE, UNTIL ATC ASKED IF WE WERE GOING TO MAKE THE XING RESTR. I WENT TO LEVEL CHANGE AT THAT TIME, BUT STILL DID NOT MAKE IT DOWN BY THE XING FIX. NO FURTHER COMMENTS FROM ATC. ABOUT THE TIME ATC WAS ASKING IF WE WERE GOING TO MAKE THE RESTR, THE CAPT CALLED AND CAME BACK UP FROM THE BACK. FACTORS CONTRIBUTING TO THIS EVENT WERE A FAILURE TO COMPLETE THE ALT CHANGE TASK BECAUSE OF SOME DISTR THAT I DON'T REMEMBER WHAT IT WAS, A DIM EXECUTE LIGHT THAT MIGHT HAVE REMINDED ME TO FINISH THE TASK, AND NOT HAVING ANOTHER PLT TO CATCH MY MISTAKE. SUPPLEMENTAL INFO FROM ACN 593879: WHILE I WAS ABSENT FROM THE FLT DECK TO USE THE RESTROOM, A CLRNC HAD BEEN ISSUED TO CROSS 50 NM NW OF DRAKE (N OF PHX) AT FL290. WHEN I RETURNED FROM THE RESTROOM, I HAD NOT BEEN INFORMED OF THE ATC ISSUED XING RESTR. AS I STRAPPED IN AND PUT MY HEADSET ON, CTR REQUESTED THAT WE START OUR DSCNT IMMEDIATELY TO COMPLY WITH THE CLRNC. AS I LOOKED AT THE NAV DISPLAY, I NOTICED THAT THE FO HAD PROGRAMMED A FIX OF DRK/01 WHICH TURNED OUT TO BE THE XING RESTR POINT. WHEN ATC CALLED TO DIRECT THE IMMEDIATELY DSCNT, THE ACFT WAS PASSING THE POINT FOR THE XING RESTR AT FL330.

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.