Narrative:

Crew showed early at airport after layover in an attempt to depart early. Door was closed eight minutes early and after completion of all checklists we called for push with clearance as is the procedure. Clearance told us to monitor ground for push. After a few minutes ground told us to hold push & contact clearance again for a full re-route clearance. After copying a lengthy clearance from clearance delivery; we proceeded to input the new flight plan into the FMS. There were few discrepancies during the process; re: spellings/names of new fixes etc; that we had to clarify with clearance again; which was time consuming; as they were obviously very busy at the time; giving other aircraft re-routes; and we had to wait our turn to for air time; to ask our needed questions. [While] inputting the new flight plan into the FMS; I called our dispatcher to let her know of our re-route; which she said she was aware of; and that she would send our new numbers via ACARS. It took a few minutes to get the new release on ACARS; and upon receiving we noticed our fuel had been brought up by about 1;200 lbs; whereupon we notified the station that we would need more fuel uploaded. It took several minutes for the fueler to show; and after finally receiving our fuel upload; and inputting the new fuel into the FMS; we proceeded to re-run the checklist. Approximately 50-55 minutes had passed since our initial door close at this time. During the process of; re-reading the checklist; and going over our final numbers; I noticed that the aircraft gw (gross weight) on du #4 was about 1;200 lbs higher than our max allowable takeoff weight. (We were landing weight limited due to the relatively short flight.) with a burn of 6;400 lbs; and a max limited landing weight of 104;000 lbs; (104;000+ 6;400 = 110;400) our max allowable takeoff weight was limited to 110;400. With the gw on du #4 showing a gw of around 111;600. This did not match up with the expected takeoff weight on the new release; and I did not feasibly see how we could possibly burn 1;200 lbs before reaching the runway. We proceeded to re-check all the numbers; and re-input everything into the FMS; in the event we had input something wrongly. After a couple of attempts and arriving at the same situation; I called our dispatcher to let her know of the problem; she re-checked all her numbers and was not able to discover if anything was wrong on her end. We then attempted to fill out an [manual weight and balance form] to see if the numbers would add up on paper. This proved a little time consuming; checking and verifying each load sheet. After totaling up the numbers we found they added up relatively close to the new dispatch. So the problem had to be in the FMS. After a few more calls working with dispatch; & and re-inputting the numbers; and an attempt with maintenance at pulling the FMS circuit breakers in an attempt to re-set the FMS; we kept arriving at the same problem. However we discovered during this process; that the FMS would add up all the numbers correctly; until the takeoff runway was inputted into the FMS; which is the final step; and should have nothing to do with the gross weight of the airplane. But upon doing so we would visibly see the gross weight on du #4 jump up by 1;200 lbs. About 1:40 minutes had transpired at this point; and I was working with maintenance on this new discovery when the gate agent asked me to open the main cabin door; which we did. Everybody was 'stumped' with the problem. But after maintenance control consulted with their heads; it was decided that we should pull all the circuit breakers for both via's [versatile integrated avionics] and do a complete reset. After powering down the via's for several minutes; and re-setting; this proved to be successful; with no further anomalies. After the power down of the via's; re-boot; fully re-loading the FMS; and re-boarding of all passengers; doors were re-closed three hours late; and flight was completed un-eventfully. I would like to say; had this occurred and the increased weight was not greater than our max allowable takeoff weight; it is quite possible the anomaly may have gone unnoticed. It was the fact that the anomaly had me heavier than our max allowable takeoff weight that brought my attention to it. It is possible that this has happened before and gone unnoticed because the increase in weight was not a concerning factor to the crew.

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Original NASA ASRS Text

Title: B717 Captain describes an FMS/VIA anomaly that results in an incorrect gross weight calculation greatly delaying a flight. Eventually the VIA is reset electrically and the flight departs with no further anomalies.

Narrative: Crew showed early at airport after layover in an attempt to depart early. Door was closed eight minutes early and after completion of all checklists we called for push with Clearance as is the procedure. Clearance told us to monitor Ground for push. After a few minutes Ground told us to hold push & contact Clearance again for a full re-route clearance. After copying a lengthy clearance from Clearance Delivery; we proceeded to input the new flight plan into the FMS. There were few discrepancies during the process; re: spellings/names of new fixes etc; that we had to clarify with Clearance again; which was time consuming; as they were obviously very busy at the time; giving other aircraft re-routes; and we had to wait our turn to for air time; to ask our needed questions. [While] inputting the new flight plan into the FMS; I called our Dispatcher to let her know of our re-route; which she said she was aware of; and that she would send our new numbers via ACARS. It took a few minutes to get the new release on ACARS; and upon receiving we noticed our fuel had been brought up by about 1;200 lbs; whereupon we notified the station that we would need more fuel uploaded. It took several minutes for the fueler to show; and after finally receiving our fuel upload; and inputting the new fuel into the FMS; we proceeded to re-run the checklist. Approximately 50-55 minutes had passed since our initial door close at this time. During the process of; re-reading the checklist; and going over our final numbers; I noticed that the aircraft GW (Gross Weight) on DU #4 was about 1;200 lbs higher than our Max Allowable Takeoff Weight. (We were landing weight limited due to the relatively short flight.) With a burn of 6;400 lbs; and a Max Limited Landing Weight of 104;000 lbs; (104;000+ 6;400 = 110;400) our Max Allowable Takeoff Weight was limited to 110;400. With the GW on DU #4 showing a GW of around 111;600. This did not match up with the expected takeoff weight on the new release; and I did not feasibly see how we could possibly burn 1;200 lbs before reaching the runway. We proceeded to re-check all the numbers; and re-input everything into the FMS; in the event we had input something wrongly. After a couple of attempts and arriving at the same situation; I called our Dispatcher to let her know of the problem; she re-checked all her numbers and was not able to discover if anything was wrong on her end. We then attempted to fill out an [manual weight and balance form] to see if the numbers would add up on paper. This proved a little time consuming; checking and verifying each Load Sheet. After totaling up the numbers we found they added up relatively close to the new dispatch. So the problem had to be in the FMS. After a few more calls working with Dispatch; & and re-inputting the numbers; and an attempt with Maintenance at pulling the FMS circuit breakers in an attempt to re-set the FMS; we kept arriving at the same problem. However we discovered during this process; that the FMS would add up all the numbers correctly; until the takeoff runway was inputted into the FMS; which is the final step; and should have nothing to do with the Gross Weight of the Airplane. But upon doing so we would visibly see the Gross Weight on DU #4 jump up by 1;200 lbs. About 1:40 minutes had transpired at this point; and I was working with Maintenance on this new discovery when the Gate Agent asked me to open the Main Cabin Door; which we did. Everybody was 'stumped' with the problem. But after Maintenance Control consulted with their heads; it was decided that we should pull all the circuit breakers for both VIA's [Versatile Integrated Avionics] and do a complete reset. After powering down the VIA's for several minutes; and re-setting; this proved to be successful; with no further anomalies. After the power down of the VIA's; re-boot; fully re-loading the FMS; and re-boarding of all passengers; doors were re-closed three hours late; and flight was completed un-eventfully. I would like to say; had this occurred and the increased weight was not greater than our Max Allowable Takeoff Weight; it is quite possible the anomaly may have gone unnoticed. It was the fact that the anomaly had me heavier than our Max Allowable Takeoff Weight that brought my attention to it. It is possible that this has happened before and gone unnoticed because the increase in weight was not a concerning factor to the crew.

Data retrieved from NASA's ASRS site as of July 2013 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.