Narrative:

Received clearance from ZDC to 'cross 35 southwest of elkins at 240.' first officer (flying) attempted to do this on the FMC by looking at the FMC (asbur, bogge, rocka, oakle, perri, perks) finding the closest to 35 and attempting an offset fix, entering it, determining crossing altitude, entering it and executing a VNAV descent. I was assuming he was merely picking a fix (perri) that would meet the requirements and executing a descent to FL240 at that point. After numerous attempts to unsuccessfully accomplish this, the first officer started a slow descent and returned to the FMC, apparently obsessed about accomplishing his task. When I realized he was 1) not doing what I thought he was doing, and 2) had the FMC panel in a state that was not navigable. I called the fix page up and entered elkins. We were at that time crossing the point specified and were 2000 ft high. I called center, apologized and maximized descent. I also upbraided myself for not immediately going to the fix page and backing up the descent with a mental calculation. As a more 'mature' pilot, I am seeing more and more of this scenario, i.e., a fairly good pilot turns into a 'computer nerd' when given a non standard clearance or crossing restr, and becomes completely fascinated/challenged/ absorbed with putting it in the FMC at the expense of common sense, and in this case a flight profile meeting ATC clearance. Attempting an offset fix is problematic at best, but impossible at the time frame we had. My errors were assuming he was simply putting in FL240 at perri, and not calling up elkins of the fix page as a backup. The bottom line for 'computer nerds' plting an aircraft -- unlike your home computer time and the aircraft don't stop when you have an input problem.

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Original NASA ASRS Text

Title: ADVANCED AUTOMATED COCKPIT MGMNT.

Narrative: RECEIVED CLRNC FROM ZDC TO 'CROSS 35 SW OF ELKINS AT 240.' FO (FLYING) ATTEMPTED TO DO THIS ON THE FMC BY LOOKING AT THE FMC (ASBUR, BOGGE, ROCKA, OAKLE, PERRI, PERKS) FINDING THE CLOSEST TO 35 AND ATTEMPTING AN OFFSET FIX, ENTERING IT, DETERMINING XING ALT, ENTERING IT AND EXECUTING A VNAV DSCNT. I WAS ASSUMING HE WAS MERELY PICKING A FIX (PERRI) THAT WOULD MEET THE REQUIREMENTS AND EXECUTING A DSCNT TO FL240 AT THAT POINT. AFTER NUMEROUS ATTEMPTS TO UNSUCCESSFULLY ACCOMPLISH THIS, THE FO STARTED A SLOW DSCNT AND RETURNED TO THE FMC, APPARENTLY OBSESSED ABOUT ACCOMPLISHING HIS TASK. WHEN I REALIZED HE WAS 1) NOT DOING WHAT I THOUGHT HE WAS DOING, AND 2) HAD THE FMC PANEL IN A STATE THAT WAS NOT NAVIGABLE. I CALLED THE FIX PAGE UP AND ENTERED ELKINS. WE WERE AT THAT TIME XING THE POINT SPECIFIED AND WERE 2000 FT HIGH. I CALLED CTR, APOLOGIZED AND MAXIMIZED DSCNT. I ALSO UPBRAIDED MYSELF FOR NOT IMMEDIATELY GOING TO THE FIX PAGE AND BACKING UP THE DSCNT WITH A MENTAL CALCULATION. AS A MORE 'MATURE' PLT, I AM SEEING MORE AND MORE OF THIS SCENARIO, I.E., A FAIRLY GOOD PLT TURNS INTO A 'COMPUTER NERD' WHEN GIVEN A NON STANDARD CLRNC OR XING RESTR, AND BECOMES COMPLETELY FASCINATED/CHALLENGED/ ABSORBED WITH PUTTING IT IN THE FMC AT THE EXPENSE OF COMMON SENSE, AND IN THIS CASE A FLT PROFILE MEETING ATC CLRNC. ATTEMPTING AN OFFSET FIX IS PROBLEMATIC AT BEST, BUT IMPOSSIBLE AT THE TIME FRAME WE HAD. MY ERRORS WERE ASSUMING HE WAS SIMPLY PUTTING IN FL240 AT PERRI, AND NOT CALLING UP ELKINS OF THE FIX PAGE AS A BACKUP. THE BOTTOM LINE FOR 'COMPUTER NERDS' PLTING AN ACFT -- UNLIKE YOUR HOME COMPUTER TIME AND THE ACFT DON'T STOP WHEN YOU HAVE AN INPUT PROB.

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.