Narrative:

During preflight, I entered the filed routing into the FMC. When clearance was received via ACARS, 2 routings appeared. The first showed a somewhat different routing to tcc. The second, and last, showed as filed. We interpreted this to mean that the filed course was the current course, when, in fact, the reverse was true. Not until abq, were we questioned by center regarding our route. We carried the discussion to the next sector, who didn't think it created a problem, and he cleared us directly to fam. Researching the flight operations manual revealed that when 2 clrncs appear on ACARS, the current clearance is the top clearance. It amends what is below. A lifetime of reading words typed on paper instills in most of us that the last message typed is the most current. Computer generated messages displayed on a screen are not bound by mechanically typed formats. Perhaps a bulletin highlighting this ACARS feature would prevent future occurrences. Of course, a simple 'amended routing' alert prior to the routing display would totally solve the problem. Routings are too important to be displayed cryptically. Supplemental information from acn 247586: we had received our route clearance from phx clearance via pre departure clearance procedures on our ACARS system and had not verbally talked to clearance delivery. The ACARS screen showed 2 clrncs to tcc, the first being the route that ATC expected us to be flying, and the second (which matched our filed route) the one we assumed was the correct routing. We had decided that the amended routing was a computer misprint and that the original flight plan that was printed below was the correct clearance.

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Original NASA ASRS Text

Title: AN ACR MLG CREW FAILED TO NOTE THE CHANGES IN ITS AIRWAYS ROUTING FROM PDC.

Narrative: DURING PREFLT, I ENTERED THE FILED ROUTING INTO THE FMC. WHEN CLRNC WAS RECEIVED VIA ACARS, 2 ROUTINGS APPEARED. THE FIRST SHOWED A SOMEWHAT DIFFERENT ROUTING TO TCC. THE SECOND, AND LAST, SHOWED AS FILED. WE INTERPRETED THIS TO MEAN THAT THE FILED COURSE WAS THE CURRENT COURSE, WHEN, IN FACT, THE REVERSE WAS TRUE. NOT UNTIL ABQ, WERE WE QUESTIONED BY CTR REGARDING OUR RTE. WE CARRIED THE DISCUSSION TO THE NEXT SECTOR, WHO DIDN'T THINK IT CREATED A PROB, AND HE CLRED US DIRECTLY TO FAM. RESEARCHING THE FLT OPS MANUAL REVEALED THAT WHEN 2 CLRNCS APPEAR ON ACARS, THE CURRENT CLRNC IS THE TOP CLRNC. IT AMENDS WHAT IS BELOW. A LIFETIME OF READING WORDS TYPED ON PAPER INSTILLS IN MOST OF US THAT THE LAST MESSAGE TYPED IS THE MOST CURRENT. COMPUTER GENERATED MESSAGES DISPLAYED ON A SCREEN ARE NOT BOUND BY MECHANICALLY TYPED FORMATS. PERHAPS A BULLETIN HIGHLIGHTING THIS ACARS FEATURE WOULD PREVENT FUTURE OCCURRENCES. OF COURSE, A SIMPLE 'AMENDED ROUTING' ALERT PRIOR TO THE ROUTING DISPLAY WOULD TOTALLY SOLVE THE PROB. ROUTINGS ARE TOO IMPORTANT TO BE DISPLAYED CRYPTICALLY. SUPPLEMENTAL INFO FROM ACN 247586: WE HAD RECEIVED OUR RTE CLRNC FROM PHX CLRNC VIA PDC PROCS ON OUR ACARS SYS AND HAD NOT VERBALLY TALKED TO CLRNC DELIVERY. THE ACARS SCREEN SHOWED 2 CLRNCS TO TCC, THE FIRST BEING THE RTE THAT ATC EXPECTED US TO BE FLYING, AND THE SECOND (WHICH MATCHED OUR FILED RTE) THE ONE WE ASSUMED WAS THE CORRECT ROUTING. WE HAD DECIDED THAT THE AMENDED ROUTING WAS A COMPUTER MISPRINT AND THAT THE ORIGINAL FLT PLAN THAT WAS PRINTED BELOW WAS THE CORRECT 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.