Narrative:

During descent into ord (high traffic volume); we were advised of holding and given a new clearance limit of benky; (a fix on the bdf 5 arrival) hold as published; 12;000 ft; with an efc of just over 30 minutes from the current time. We were not dispatched with any holding fuel; however we did have 1;500 pounds extra and an alternate of grand rapids. When we entered the hold at benky; we had over 5;400 pounds of fuel on board. We calculated our own bingo number using our best estimates; and came up with a number of about 4;400 pounds (fuel to complete the current segment to ord; ILS approach; miss; fly to alternate; approach; land with minimum fuel.) we advised dispatch as required; and sent them our pertinent numbers required for them to issue our bingo number and alternate. We were holding at benky; which is about 100 miles from ord on the arrival plus the approach; or 50 miles straight line distance. We would still need to complete an approach to what would most likely be runway 28 or 27L. Dispatch came back with the following numbers: sbn alternate burn - 272 pounds reserve - 2;237 alternate burn - 1;167 min - 3;676 bingo - 3.8 in both pilot's opinions; these numbers are not even close to realistic. I do not believe the aircraft can glide at idle thrust that distance without burning over 272 pounds. This is a common issue when issued a hold; and dispatch provides bingo numbers. My problem with this event and this occurrence in general is that we as pilots have been conditioned to never believe dispatch numbers when issued a hold; which leads to other problems. In a worst case scenario; a pilot may actually believe these completely unrealistic numbers; and find out how wrong they are when they become critically low on fuel. In actuality; we were cleared to leave the hold early with 5;100 pounds of fuel; flew a straight in approach to runway 4R; and landed with 4;500 pounds of fuel. We burned over 500 pounds of fuel to complete the flight from the holding fix; which is about 100% more than dispatch had planned. Also; this was the absolute best case scenario; as we left the hold and without any vectoring immediately flew northwest (almost exactly our current heading) to intercept the ILS 4R; in basically a continuous descent; no vectors; without having to fly a downwind leg at all; at an economical speed 210 KTS. In other words; there is no possible way to fly from the hold; to any runway at ord; and use 272 pounds of fuel. It is an absolute impossibility.had we actually had to fly a full ILS to 28 or 27L; (or any other runway at ord) it would have been at least 1;000 pounds. Now add a missed approach; a flight to south bend; another approach; and we would have been in a fuel emergency scenario had we used the dispatch provided numbers. When we questioned our dispatcher through ACARS about the numbers they provided us; the reply alluded to the fact our dispatcher simply plugged in our numbers to the computer and sent them back. The dispatcher never sent back more realistic numbers at any point; even after we told them that 272 pounds of fuel to finish the flight was unreasonable. The idea of leaving benky with 3;800 pounds of fuel (the dispatch computed bingo number); flying a normal approach into ord; going missed; flying to sbn (south bend); and landing with over 2;300 pounds of fuel is absolutely impossible in the real world. Dispatch can use software to create these numbers all day long; but in the environments we operate in; they are simply not valid or safe. I believe this issue has led many pilots here to ignore dispatch when they are needed the most. It also leads to a sense that we are completely on our own; without any help whatsoever when we do need it. My other safety concern is that someone may actually use these made up numbers someday and find themselves in a very bad position. I also believe our fuel training is inadequate; with no emphasis on real world scenarios.

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Original NASA ASRS Text

Title: EMB170 Captain laments the unrealistic fuel numbers provided by Dispatch after being advised of a 30 minute hold arriving ORD. The reporter is able to leave the hold early and land safely at ORD.

Narrative: During descent into ORD (high traffic volume); we were advised of holding and given a new clearance limit of BENKY; (a fix on the BDF 5 arrival) hold as published; 12;000 FT; with an EFC of just over 30 minutes from the current time. We were not dispatched with any holding fuel; however we did have 1;500 LBS extra and an alternate of Grand Rapids. When we entered the hold at BENKY; we had over 5;400 LBS of fuel on board. We calculated our own bingo number using our best estimates; and came up with a number of about 4;400 LBS (fuel to complete the current segment to ORD; ILS approach; miss; fly to alternate; approach; land with minimum fuel.) We advised Dispatch as required; and sent them our pertinent numbers required for them to issue our bingo number and alternate. We were holding at BENKY; which is about 100 miles from ORD on the arrival plus the approach; or 50 miles straight line distance. We would still need to complete an approach to what would most likely be Runway 28 or 27L. Dispatch came back with the following numbers: SBN alternate Burn - 272 LBS Reserve - 2;237 Alternate Burn - 1;167 Min - 3;676 Bingo - 3.8 in both pilot's opinions; these numbers are not even close to realistic. I do not believe the aircraft can glide at idle thrust that distance without burning over 272 LBS. This is a common issue when issued a hold; and Dispatch provides bingo numbers. My problem with this event and this occurrence in general is that we as pilots have been conditioned to never believe Dispatch numbers when issued a hold; which leads to other problems. In a worst case scenario; a pilot may actually believe these completely unrealistic numbers; and find out how wrong they are when they become critically low on fuel. In actuality; we were cleared to leave the hold early with 5;100 LBS of fuel; flew a straight in approach to Runway 4R; and landed with 4;500 LBS of fuel. We burned over 500 LBS of fuel to complete the flight from the holding fix; which is about 100% more than Dispatch had planned. Also; this was the absolute best case scenario; as we left the hold and without any vectoring immediately flew northwest (almost exactly our current heading) to intercept the ILS 4R; in basically a continuous descent; no vectors; without having to fly a downwind leg at all; at an economical speed 210 KTS. In other words; there is no possible way to fly from the hold; to ANY runway at ORD; and use 272 LBS of fuel. It is an absolute impossibility.Had we actually had to fly a full ILS to 28 or 27L; (or any other runway at ORD) it would have been at least 1;000 LBS. Now add a missed approach; a flight to South Bend; another approach; and we would have been in a fuel emergency scenario had we used the Dispatch provided numbers. When we questioned our Dispatcher through ACARS about the numbers they provided us; the reply alluded to the fact our Dispatcher simply plugged in our numbers to the computer and sent them back. The Dispatcher never sent back more realistic numbers at any point; even after we told them that 272 LBS of fuel to finish the flight was unreasonable. The idea of leaving BENKY with 3;800 LBS of fuel (the Dispatch computed bingo number); flying a normal approach into ORD; going missed; flying to SBN (South Bend); and landing with over 2;300 LBS of fuel is absolutely impossible in the real world. Dispatch can use software to create these numbers all day long; but in the environments we operate in; they are simply not valid or safe. I believe this issue has led many pilots here to ignore dispatch when they are needed the most. It also leads to a sense that we are completely on our own; without any help whatsoever when we do need it. My other safety concern is that someone may actually use these made up numbers someday and find themselves in a very bad position. I also believe our fuel training is inadequate; with no emphasis on real world scenarios.

Data retrieved from NASA's ASRS site as of April 2012 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.