Explain This Please?

Virgin have announced that they will tow their aircraft to the runways saving 2 tons of fuel per flight??

Do these planes really use 2 tons of fuel just to taxi 10 mins??

If yes, how much fuel do they use to fly to Florida ??


item below,
"By towing its Boeing 747-400 aircraft to take-off areas at London airports during December it said it could save up to two tonnes of fuel per flight.

Aircraft will be towed to Heathrow and Gatwick runways to cut fuel burning."

[HighFlyer]

Hi there,

Take a look at ths thread, where this notion is already being covered for more background information.

Thanks,
Sarah

[preiffer]

744's use something in the order of an average 10 tonnes of fuel per hour, on a long haul flight.

Take a look at ths thread, where this notion is already being covered for more background information.

Same poster, Sarah - I think they were just reposting it here to avoid going OT.

VS.

2 tonnes is a worse case scenario, you only need to look at the amount of aircraft lining up awaiting take off to realise the reason why.

I seem to think that the daily consumption of fuel by heathrow is around 16 million litres. Although ISTC.

Around 370 fully laden tankers @ 44000 litres each. Assuming that an unladen tanker is around 12 - 14 tons (estimate) then 44,000 litres fuel weighs around 30 tonnes ... roughly, so assuming my calculations are correct, that makes it around 2500 / 3000 litres to taxi to the gate - wow [:0]

edit : just had a look at the consumption when flying, which is around 25 litres per mile - so taxing (and all the waiting around) looks to be pretty uneconomical (assuming my calculations are correct)

David

Last summer we were flying from Gatwick to Fuenteventura in the Canary islands. As we approached the runway, we turned back and parked, as a nervous passenger insisted on getting off, with the a/c running. We then had to wait for the fuel to be "topped off" again, so there must be a "reasonable" amount used on the ground....

I find that incredible that they needed to top off in order to get safely to the destination. I always thought there were strict rules about fuel reserves etc. very strange.

The same happened to me on a Virgin flight out of JFK in 2003. One of the exit doors wouldn't function and the crew announced that it would be out of action. Not sure if the captain didn't know but by the time we got to the runway he decided to turn back to fix it. A plastic spoon was lodged in the door apparantly and once removed we waited to be refuelled. I suppose if the reserve fuel is burnt before take off it won't be there when needed up in the air!

Modern airlines make VERY careful calculations in their flight planning to work out the correct fuel load for each particular route taking into account aircraft weight, routing, overshoot in case of emergency or a diversion to another airfield. There is no profit in tankering fuel around.

David, the way to work it out is to divide the KG figure by the specific gravity of the fuel. Today we had fuel of an SG of .807, therefore 2 tonnes would equate to 2478 litres.

Originally posted by Denzil
David, the way to work it out is to divide the KG figure by the specific gravity of the fuel. Today we had fuel of an SG of .807, therefore 2 tonnes would equate to 2478 litres.

Thanks Denzil, not a bad guestimate at 2500 - 3000 litres

I think that depending on the ratio of unl to derv the 44 tonne tankers can carry around 40,000 litres of fuel although the sg of JET A will be different to unl / derv. [:w]

David