When fuelling planes do they always fill the tanks right up or do they only put in the correct amount?

Question

i`m just wondering if the required amount is put in or if they fill the tanks right up incase there are problems or hold ups, given that one type of plane can serve a vareity of distances ie a 737 can fly between newcastle and amsterdam as well as newcastle to barcelona which is double the distance

Answer 1

It's the amount calculated as required for the flight, plus sufficient for a diversion if the destination airport is unavailable, plus a safety margin.  F'rinstance a flight into Gatwick will have sufficient to reach there, plus enough for a diversion to Heathrow, or Stanstead, or Luton, or Coventry etc, plus the statutory safety margin.  Unnecessary fuel is unnecessary weight. However, sometimes extra fuel is carried if there's any doubt about it being available at the destination.

(I agree with John B, the three most useless things for a pilot are the fuel he didn't upload, the runway behind him and the altitude above him . . .)

Answer 2

Normally the aircraft is filled with enough fuel for the trip, plus a reserve for safety.  The tanks are not completely filled unless a full fuel load is necessary for the flight.  Flying with full tanks when a full fuel load isn't necessary is expensive, because it takes more fuel to transport the weight of the full tanks.  It also reduces the amount of passengers and cargo that can be carried, and if the plane must land prematurely, it may have to dump fuel in order to not exceed its maximum landing weight.  So only the fuel actually needed (plus the safety reserve) actually is loaded.

Answer 3

they only fill the tanks up to what is required for the flight, plus extra for safety precautions in case they need to divert to another airport.

There once was an episode on Mayday (Air Crash Investigation, in the US) that aired on Discovery Channel about an Airliner that was hijacked and the hijackers believed that the plane had enough fuel on board and could take them to Australia, because they believed that there was full tanks of fuel (which would have had enough fuel to get to Australia), and not just enough for the trip plus extra for safety measures.

Answer 4

The answer is ... they put in the correct amount.

And sometimes, the correct amount is to fill them all the way up.

Answer 5

They only put in what is required plus some extra reserves.

Answer 6

Due to the current high cost of fuel, there is a specific amount that is loaded depending on the trip and seldom any reason to top off the tanks. When I was flying in the Air Force ( a fighter interceptor squadron), We only loaded about enough to get off the ground and then went hunting for an airborne gas station. In all kidding aside, that gave me a better ordinance load and once in the air we would re-fuel according to the mission.

Answer 7

They only fill up the tanks for whatever is required plus enough to an alternate and holding fuel. Filling up the tanks is prohibitively expensive because the fuel consumption will be higher and you may not even be able to fill it up because of landing weight limitations etc.

Answer 8

Fuel burns are calculated very accurately and then a safe and legal reserve is added to that number to get something known as a "dispatch minimum" fuel amount.  this is typically the number that is put on board, rather than full tanks.

There are a couple of reasons for this.  1) taking extra fuel cuts into the payload available to use for passengers, cargo, or other revenue streams, and this is a business.  2) Fuel is HEAVY.  Heavy airplanes burn more fuel, meaning that if you take more fuel, you use more fuel, and therefore need more fuel...and fuel is expensive.  A pretty safe estimation is that it takes 10% to tanker fuel.  So if you tanker an extra 5000 pounds, you can expect to burn an additional 500 pounds (at 6.7 pounds per gallon, thats approximately 75 gallons...not exactly chump change)

Airlines and professional operators everywhere tend to fuel down to almost an absolute minimum that is required to make the flight both safe and legal.  At my company, we have a certain threshold below which we cannot drop.  That threshold is 45 minutes of reserve after touching down.  If it looks like we are going to drop below that we declare "minimum fuel" and if it looks like we are going to land with less than a 30 minute reserve we declare an emergency.

Answer 9

Fuel quantity is mission specific, with reserves in case the need to divert arises.

Answer 10

There is a correct amount. However, having said that, nothing is more useless than fuel you left in the truck. Other than the runway behind you.