Narrative:

In the vicinity of fnt, the ZOB controller issued a clearance to cross 70 mi northeast of pmm at FL310. The clearance was read back as I selected the legs page on the CDU. I noted that the 2 segment distances prior to pmm totaled 71 mi (according to the FMC legs page) and was about to enter the crossing restr at dewit as the PNF began to clear the leg segments prior to pmm. I pointed out the distances between the 2 leg segments and asked the PNF the total distance. He responded, '71 mi,' and I said, 'let's do it this way.' I then simply entered the FL310 restr on the dewit segment line. At least I thought I entered the crossing restr on the dewit line which was, in fact, 71 mi prior to pmm. I have witnessed many errors occur when incorrect distances were added on the legs page in the past and had always discovered the error almost immediately because of my practice to manually tune the VOR upon which a crossing restr was based or enter the VOR or intersection on which a restr was based on the fix page of the CDU and checking the mileage. Many times I would do both. I don't know why I failed to make either confirmation xchk in this instance. Perhaps one reason was that we were nearing the end of a 9 hour flight segment and I was looking forward to some sleep as soon as I reached home. I had only 1 day off at home between a 10 day trip to japan as the member of a visual aids panel before beginning the current 6 day european flight sequence. This event took place on day 3 of the european sequence returning to chicago (my home but not my crew domicile) after a frankfurt layover during which my sleep pattern was substantially disrupted. As we approached dewit, the controller asked that we start down. We acknowledged and the controller then asked if we had received the clearance to cross 70 mi northeast of pmm at FL310. The first officer responded that we had received the clearance. The controller then stated that he showed our flight 70 mi northeast of pmm now. Both the first officer and I recognized the error when that statement was made. The first officer responded that he had made an incorrect entry into 'the machine' and that we were descending. The controller then stated, 'no problem.' the first officer apologized for our error and the controller again said, 'there's no problem.' all was normal for the remainder of the flight and I believe that no traffic conflict existed but the restr was due to an agreement between ZOB and ZAU. The next evening en route to frankfurt once again, I attempted to discover why I had failed to properly enter the crossing restr even considering the possibility of fatigue the previous afternoon. It was evident that 1 of 2 possibilities existed. First was that I simply entered it on the wrong line of the CDU legs page. Although this possibility always exists, I have difficulty believing it because both of us agreed that the entry was correct. The other possibility is that my entry was made just as we crossed fnt and the CDU legs page advanced all waypoints 1 line as we passed and the entry was made. Thus, even though the entry appeared to have been made on the dewit line, the FMC accepted it on the haste line as the screen blanked momentarily when the waypoints were advanced. I have seen this occur a number of times but didn't notice it this time, nor did the first officer who is no slouch and conducts his duties in a most professional manner. In any case, the failure to confirm the entry with the fix page or manual selection of the pmm VOR was mine and was the actual reason for the error.

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Original NASA ASRS Text

Title: FLC FAILS TO COMPLY WITH XING RESTR.

Narrative: IN THE VICINITY OF FNT, THE ZOB CTLR ISSUED A CLRNC TO CROSS 70 MI NE OF PMM AT FL310. THE CLRNC WAS READ BACK AS I SELECTED THE LEGS PAGE ON THE CDU. I NOTED THAT THE 2 SEGMENT DISTANCES PRIOR TO PMM TOTALED 71 MI (ACCORDING TO THE FMC LEGS PAGE) AND WAS ABOUT TO ENTER THE XING RESTR AT DEWIT AS THE PNF BEGAN TO CLR THE LEG SEGMENTS PRIOR TO PMM. I POINTED OUT THE DISTANCES BTWN THE 2 LEG SEGMENTS AND ASKED THE PNF THE TOTAL DISTANCE. HE RESPONDED, '71 MI,' AND I SAID, 'LET'S DO IT THIS WAY.' I THEN SIMPLY ENTERED THE FL310 RESTR ON THE DEWIT SEGMENT LINE. AT LEAST I THOUGHT I ENTERED THE XING RESTR ON THE DEWIT LINE WHICH WAS, IN FACT, 71 MI PRIOR TO PMM. I HAVE WITNESSED MANY ERRORS OCCUR WHEN INCORRECT DISTANCES WERE ADDED ON THE LEGS PAGE IN THE PAST AND HAD ALWAYS DISCOVERED THE ERROR ALMOST IMMEDIATELY BECAUSE OF MY PRACTICE TO MANUALLY TUNE THE VOR UPON WHICH A XING RESTR WAS BASED OR ENTER THE VOR OR INTXN ON WHICH A RESTR WAS BASED ON THE FIX PAGE OF THE CDU AND CHKING THE MILEAGE. MANY TIMES I WOULD DO BOTH. I DON'T KNOW WHY I FAILED TO MAKE EITHER CONFIRMATION XCHK IN THIS INSTANCE. PERHAPS ONE REASON WAS THAT WE WERE NEARING THE END OF A 9 HR FLT SEGMENT AND I WAS LOOKING FORWARD TO SOME SLEEP AS SOON AS I REACHED HOME. I HAD ONLY 1 DAY OFF AT HOME BTWN A 10 DAY TRIP TO JAPAN AS THE MEMBER OF A VISUAL AIDS PANEL BEFORE BEGINNING THE CURRENT 6 DAY EUROPEAN FLT SEQUENCE. THIS EVENT TOOK PLACE ON DAY 3 OF THE EUROPEAN SEQUENCE RETURNING TO CHICAGO (MY HOME BUT NOT MY CREW DOMICILE) AFTER A FRANKFURT LAYOVER DURING WHICH MY SLEEP PATTERN WAS SUBSTANTIALLY DISRUPTED. AS WE APCHED DEWIT, THE CTLR ASKED THAT WE START DOWN. WE ACKNOWLEDGED AND THE CTLR THEN ASKED IF WE HAD RECEIVED THE CLRNC TO CROSS 70 MI NE OF PMM AT FL310. THE FO RESPONDED THAT WE HAD RECEIVED THE CLRNC. THE CTLR THEN STATED THAT HE SHOWED OUR FLT 70 MI NE OF PMM NOW. BOTH THE FO AND I RECOGNIZED THE ERROR WHEN THAT STATEMENT WAS MADE. THE FO RESPONDED THAT HE HAD MADE AN INCORRECT ENTRY INTO 'THE MACHINE' AND THAT WE WERE DSNDING. THE CTLR THEN STATED, 'NO PROB.' THE FO APOLOGIZED FOR OUR ERROR AND THE CTLR AGAIN SAID, 'THERE'S NO PROB.' ALL WAS NORMAL FOR THE REMAINDER OF THE FLT AND I BELIEVE THAT NO TFC CONFLICT EXISTED BUT THE RESTR WAS DUE TO AN AGREEMENT BTWN ZOB AND ZAU. THE NEXT EVENING ENRTE TO FRANKFURT ONCE AGAIN, I ATTEMPTED TO DISCOVER WHY I HAD FAILED TO PROPERLY ENTER THE XING RESTR EVEN CONSIDERING THE POSSIBILITY OF FATIGUE THE PREVIOUS AFTERNOON. IT WAS EVIDENT THAT 1 OF 2 POSSIBILITIES EXISTED. FIRST WAS THAT I SIMPLY ENTERED IT ON THE WRONG LINE OF THE CDU LEGS PAGE. ALTHOUGH THIS POSSIBILITY ALWAYS EXISTS, I HAVE DIFFICULTY BELIEVING IT BECAUSE BOTH OF US AGREED THAT THE ENTRY WAS CORRECT. THE OTHER POSSIBILITY IS THAT MY ENTRY WAS MADE JUST AS WE CROSSED FNT AND THE CDU LEGS PAGE ADVANCED ALL WAYPOINTS 1 LINE AS WE PASSED AND THE ENTRY WAS MADE. THUS, EVEN THOUGH THE ENTRY APPEARED TO HAVE BEEN MADE ON THE DEWIT LINE, THE FMC ACCEPTED IT ON THE HASTE LINE AS THE SCREEN BLANKED MOMENTARILY WHEN THE WAYPOINTS WERE ADVANCED. I HAVE SEEN THIS OCCUR A NUMBER OF TIMES BUT DIDN'T NOTICE IT THIS TIME, NOR DID THE FO WHO IS NO SLOUCH AND CONDUCTS HIS DUTIES IN A MOST PROFESSIONAL MANNER. IN ANY CASE, THE FAILURE TO CONFIRM THE ENTRY WITH THE FIX PAGE OR MANUAL SELECTION OF THE PMM VOR WAS MINE AND WAS THE ACTUAL REASON FOR THE ERROR.

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.