When I recently made a flight from Paris to JFK (non-stop), the pilot told us before take-off that the....?

Question

... flight time will be around 07:20, and he expects to burn about 85.9 tons of fuel (about 189 lbs)....

After landing, he told us that our total flight time was 07:21 (so just 1 min. more than planned) and we burned 187 lbs..... So only 2 lbs less than planned... So my question: Was this rather "good luck" that the planned numbers were almost the same as the real numbers, or can they really plan that accurate (I mean, a flight of around 3300 nautical miles of length, and then just 1 min. more in the air than planned is pretty good calculation)?!..

Answer 1

Airlines get rated based on on-time performance. There is no extra credit for being early. However, flying slower saves fuel and flying faster drinks more fuel fast. Generally if they're running behind they can fly a bit faster to make up the difference but often if we are running early we save some gas rather than arrive much early.  

Answer 2

Your pilot was probably flying it well, remember its how you fly it that counts, the better, slower  & smoother you fly it the more fuel you save. (aviophag... seriously I doubt the pilot would be lying especially if he's in charge of hundreds of lives.. come off it...)

Answer 3

Your captain is a professional expert, trained to do things precisely.  On the other hand, he/she could be lying.  You think?

But those numbers don't make sense.  171,800 pounds of fuel sounds about right, but the fuel burn does not compute.  Fuel burn in most ocean crossing machines will be more like 350-400 pounds per minute.

Of course the sentence you quote is chopped off, so we can't read the rest after (189 lbs) and (187 lbs).  Lbs per what?

Answer 4

You do something a few thousand times, and the information kind of builds itself.

Answer 5

They're very good at accuracy, but 1 minute more is very good luck.

Answer 6

There are some unknowns in fuel planning that can mess up calculations a bit, but if those unknowns don't get in the way, it's possible to calculate fuel burn with extreme precision.  The unknowns include unexpected winds (pilots have a good idea of what to expect, but sometimes the forecasters are slightly wrong), traffic issues, and diversions for bad weather (also somewhat predictable, but not entirely).

In good weather with no traffic problems and winds that are as predicted, the flight time and fuel will be very close to the mark.  So your captain was probably not making it up.

I've been on overseas flights lasting many hours that arrived within two or three minutes of the scheduled arrival time.

Answer 7

We have been in the air a bit shorter than those born with wings but our sophistication and knowledge is pretty far advanced. :)

Airlines know how long it takes to fly from one place to another in good and bad conditions.  Plus they have a good idea what the expected weather conditions will be.  This provides them with a very accurate number for both flight length and amount of fuel used.

Have fun!  Mistress Dolly