Narrative:

We were reassigned to ferry a broken aircraft back to the maintenance base for repair. The aircraft had inoperative slats. Maintenance was able to manually extend the slaps for the purpose of the ferry but [because we would be unable to retract them] we would have to fly the aircraft at or below 15;000 feet and at 230 KIAS per the aircraft limitations the entire 655 miles. Our first dispatch release was planned at FL370 and mach .77 with 13;000 pounds of fuel; 1;500 of which was unusable ballast. I called the dispatcher and informed him that was not possible. He did not seem to understand. I had to explain the aircraft's operating limitations due to the ferry. In addition; I explained specifically that the airspeed limitation of 230 knots was indicated; and that he would have to determine the true airspeed for the altitude flown on his end. The second release had a corrected altitude of 14;000 feet and a planned true airspeed of 309 knots. However; the fuel load remained at 13;000 pounds. The 1;500 pounds of ballast fuel still appeared on the release but was not included in the load. I again called dispatch and requested the correction. The third release had a fuel load of 14;000 pounds; which was enough based on the flight plan I was provided. I do not have access to the flight planning performance numbers that dispatch uses. I was dependent on dispatch to calculate the proper true airspeed; ground speed for the forecast wind; and fuel burn for the planned altitude. In addition; I received two pages of specific instructions from maintenance control about ferry operations with the slats and flaps stuck in the deployed position. In these pages; there is a specific instruction to increase the required mission fuel by 20 percent for flight at 8 degrees flaps. I again called dispatch after reading the notes and asked if that 20 percent was specifically part of his planned fuel burn; to which he responded 'yes.' our release included a copy of the ferry permit that indicated authorization for a one time flight at this point I accepted the dispatch and operated the flight. Upon reaching top of climb; I conducted a fuel burn analysis. We were burning 3;700 pounds per hour at 14;000 feet and 220 knots. We were indicating 270 ktas and approximately 230 kgs due to significant headwinds. The FMS was indicating a present position (ppos) direct to ZZZ flight time of approximately 2:30 minutes. The math was simple. With that data; the enroute burn would be 9;250 pounds. With a 2;400 pound reserve and 1;500 ballast; the required fuel at that position was 13;150 pounds. The aircraft only had approximately 12;300 pounds remaining. Apparently; dispatch did not have proper flight planning data available for the intended operation.I immediately notified dispatch via ACARS that a fuel stop would be required. We determined in the cockpit that ZZZ1 was along the route of flight and an on-line station. Dispatch replied with the same recommendation and we began planning for the stop. At this point; dispatch began sending us messages trying to obtain data about the aircraft's fuel on board (fob) and burn rates. I provided the answers. They then sent us what they believed to be a plan that would get us to ZZZ non-stop. I responded that their 'plan' contained fixes that were not in the aircraft's FMS database and was again planned at an unusable .77M. Dispatch again queried about the aircraft's fob and stated that they could see no reason why we couldn't make it non-stop. I put a stop to it. I told dispatch we were going to ZZZ1; to stop trying to make us push it and to start working on the diversion and a new ferry permit for the next leg. When we landed in ZZZ1; we had burned just over 7;000 pounds. Less than 7;000 pounds remained. Less reserve and ballast of 3;900 pounds; the plane had approximately 3;000 pounds of fuel left to use. Doing some quick math here; the straight line distance from ZZZ1 to ZZZ is 236 NM. At ourground speed of 230; burning 3;700 pph; we would have been 700 pounds short; which is about the same amount short we first calculated at the top of climb. It appears the dispatcher was not in possession of the necessary information to properly plan the flight.

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Original NASA ASRS Text

Title: A line flight crew; reassigned to a flaps/slats extended maintenance ferry; encountered difficulty and resistance from their Dispatcher with respect to the required fuel load and expected aircraft performance at the mandated restricted airspeed and altitude. When ultimately airborne the Dispatcher's prognostications were proven inadequate and the flight crew refused to continue without a fuel stop. Calculations of the fuel remaining during that stop predicted the useable fuel remaining would have been approximately 700 pounds less than that required to complete the journey non-stop.

Narrative: We were reassigned to ferry a broken aircraft back to the Maintenance base for repair. The aircraft had inoperative slats. Maintenance was able to manually extend the slaps for the purpose of the ferry but [because we would be unable to retract them] we would have to fly the aircraft at or below 15;000 feet and at 230 KIAS per the aircraft limitations the entire 655 miles. Our first dispatch release was planned at FL370 and Mach .77 with 13;000 pounds of fuel; 1;500 of which was unusable ballast. I called the Dispatcher and informed him that was not possible. He did not seem to understand. I had to explain the aircraft's operating limitations due to the ferry. In addition; I explained specifically that the airspeed limitation of 230 knots was indicated; and that he would have to determine the true airspeed for the altitude flown on his end. The second release had a corrected altitude of 14;000 feet and a planned true airspeed of 309 knots. However; the fuel load remained at 13;000 pounds. The 1;500 pounds of ballast fuel still appeared on the release but was not included in the load. I again called Dispatch and requested the correction. The third release had a fuel load of 14;000 pounds; which was enough based on the flight plan I was provided. I do not have access to the flight planning performance numbers that Dispatch uses. I was dependent on Dispatch to calculate the proper true airspeed; ground speed for the forecast wind; and fuel burn for the planned altitude. In addition; I received two pages of specific instructions from Maintenance Control about ferry operations with the slats and flaps stuck in the deployed position. In these pages; there is a specific instruction to increase the required mission fuel by 20 percent for flight at 8 degrees flaps. I again called Dispatch after reading the notes and asked if that 20 percent was specifically part of his planned fuel burn; to which he responded 'Yes.' Our release included a copy of the ferry permit that indicated authorization for a one time flight at this point I accepted the Dispatch and operated the flight. Upon reaching top of climb; I conducted a fuel burn analysis. We were burning 3;700 pounds per hour at 14;000 feet and 220 knots. We were indicating 270 KTAS and approximately 230 KGS due to significant headwinds. The FMS was indicating a Present Position (PPOS) direct to ZZZ flight time of approximately 2:30 minutes. The math was simple. With that data; the enroute burn would be 9;250 pounds. With a 2;400 pound reserve and 1;500 ballast; the required fuel at that position was 13;150 pounds. The aircraft only had approximately 12;300 pounds remaining. Apparently; Dispatch did not have proper flight planning data available for the intended operation.I immediately notified Dispatch via ACARS that a fuel stop would be required. We determined in the cockpit that ZZZ1 was along the route of flight and an on-line station. Dispatch replied with the same recommendation and we began planning for the stop. At this point; Dispatch began sending us messages trying to obtain data about the aircraft's Fuel On Board (FOB) and burn rates. I provided the answers. They then sent us what they believed to be a plan that would get us to ZZZ non-stop. I responded that their 'plan' contained fixes that were not in the aircraft's FMS database and was again planned at an unusable .77M. Dispatch again queried about the aircraft's FOB and stated that they could see no reason why we couldn't make it non-stop. I put a stop to it. I told dispatch we were going to ZZZ1; to stop trying to make us push it and to start working on the diversion and a new ferry permit for the next leg. When we landed in ZZZ1; we had burned just over 7;000 pounds. Less than 7;000 pounds remained. Less reserve and ballast of 3;900 pounds; the plane had approximately 3;000 pounds of fuel left to use. Doing some quick math here; the straight line distance from ZZZ1 to ZZZ is 236 NM. At ourground speed of 230; burning 3;700 PPH; we would have been 700 pounds short; which is about the same amount short we first calculated at the top of climb. It appears the Dispatcher was not in possession of the necessary information to properly plan the flight.

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.