Narrative:

Problem: missed crossing restriction altitude. Successive dscnts and crossing restrictions with each changing controller. Had been cleared to FL190, to cross 30 NM south of sie VOR at 15000 ft. Restriction had been programmed into FMC computer, but I must not have properly engaged the computer. When changed to frequency 127.70, the controller queried our clearance to 15000 ft. I confirmed it -- believing I still had approximately 30 mi to go -- but in fact, I was about 3 mi from the crossing. Controller said ok -- just descend to 15000 ft, which I did. Contributing factors: repeated difficulty had been experienced with setting lower altitudes into the FMC to satisfy each new restriction. Sometimes without success. Often when making dscnts with rapidly changing parameters, the automated cockpit becomes unwieldy -- and becomes a distraction to flying the aircraft. Human performance considerations: flight was last leg of a 4-DAY trip -- accumulating 25+ hours in the last 80 hours. A layover of about 3 hours was experienced between previous and current flight. A certain amount of fatigue was felt -- plus anger at knowing crew was subject to possible drug test on arrival -- combing with frustration and inability to manage the FMC -- added to the distraction of adhering to the clearance.

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Original NASA ASRS Text

Title: CAPT OF MLG ACR ACFT ALLOWED THE ACFT TO UNDERSHOOT DURING DSCNT CAUSING AN ALT XING RESTRICTION NOT TO BE MET. THERE WAS NO KNOWN CONFLICT WITH OTHER TFC.

Narrative: PROBLEM: MISSED XING RESTRICTION ALT. SUCCESSIVE DSCNTS AND XING RESTRICTIONS WITH EACH CHANGING CTLR. HAD BEEN CLRED TO FL190, TO CROSS 30 NM S OF SIE VOR AT 15000 FT. RESTRICTION HAD BEEN PROGRAMMED INTO FMC COMPUTER, BUT I MUST NOT HAVE PROPERLY ENGAGED THE COMPUTER. WHEN CHANGED TO FREQ 127.70, THE CTLR QUERIED OUR CLRNC TO 15000 FT. I CONFIRMED IT -- BELIEVING I STILL HAD APPROX 30 MI TO GO -- BUT IN FACT, I WAS ABOUT 3 MI FROM THE XING. CTLR SAID OK -- JUST DSND TO 15000 FT, WHICH I DID. CONTRIBUTING FACTORS: REPEATED DIFFICULTY HAD BEEN EXPERIENCED WITH SETTING LOWER ALTS INTO THE FMC TO SATISFY EACH NEW RESTRICTION. SOMETIMES WITHOUT SUCCESS. OFTEN WHEN MAKING DSCNTS WITH RAPIDLY CHANGING PARAMETERS, THE AUTOMATED COCKPIT BECOMES UNWIELDY -- AND BECOMES A DISTR TO FLYING THE ACFT. HUMAN PERFORMANCE CONSIDERATIONS: FLT WAS LAST LEG OF A 4-DAY TRIP -- ACCUMULATING 25+ HRS IN THE LAST 80 HRS. A LAYOVER OF ABOUT 3 HRS WAS EXPERIENCED BTWN PREVIOUS AND CURRENT FLT. A CERTAIN AMOUNT OF FATIGUE WAS FELT -- PLUS ANGER AT KNOWING CREW WAS SUBJECT TO POSSIBLE DRUG TEST ON ARR -- COMBING WITH FRUSTRATION AND INABILITY TO MANAGE THE FMC -- ADDED TO THE DISTR OF ADHERING TO THE CLRNC.

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.