B777 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 140; Flight Crew Total 23500; Flight Crew Type 3000
Communication Breakdown
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem
Company Policy
Dispatch had 1 hour (3439 lbs) of taxi fuel on board the aircraft due to snow and de-ice. When the fuel sheet got to the cockpit we had an extra 500 lbs of fuel over requested. We deiced at the remote parking spot. If we could have taxied straight forward we were less than 500 feet from the departure runway. During deicing it became obvious that we would weight about 514.0 for takeoff; and we had received our final weights showing a takeoff weight of 510.5. We were unable to override this takeoff weight to get V speeds for a 514.0 take-off weight.We had to get Dispatch to give us the numbers for wet runway; anti-ice on; and 514.0 weight. Crews should be able to override the takeoff weight to get correct numbers. Does this mean that any time we have not burned the complete taxi fuel we are not legal for takeoff?
Prior to pushback from a hardstand we received our final weight manifest where the ZFW increased 91 pounds. Our actual pushback weight was 514.3. Our performance figures for RWY 25C limited us to a MTOG of 545.0; ASSUM WT of 510.5; and a MAX EPR TOG of 510.5. We did not need the full compliment of taxi fuel given for the weather conditions (1+00) so we tried to override the TOG in ACARS to 513.5 for an 800 pound taxi burn. The SABRE ACARS data and V-speeds returned on multiple occasions were for 510.5 which was the original TOG and ASSUMED TOG. Since we were heavier than planned; we called Dispatch discussing the problem. After about 5 minutes; Dispatch was able to pull up the weights for our airfield conditions and an actual weight of 513.5 and commensurate V-speeds. Dispatch sent the new ACARS data over the cockpit printer. 9/10 line trips have a drop off of the ZFW which makes the planned V-speeds very conservative. In this case; the ACARS v-speeds generated for a 510.5 aircraft were ILLEGAL and potentially unsafe. Why can a Dispatcher override the TOG but the operating crew not do so for the actual conditions? SABRE has some serious programming errors and the potential for some seriously erroneous data being forwarded to the crew since the ACARS generated V-speeds are procedurally necessary according to SOP.
Crew is unable to modify and correct outdated takeoff data supplied by Dispatch.