Fuel Payload versus Saving Money

[Roverman]

http://www.dailymail.co.uk/news/art...-flying-planes-near-fuel-tanks-cut-costs.html

Although the date is Sept 2012 I'm sure I've read this story in the paper this week and it got me wondering if this sort of thing happens on the trains with the diesel units? Do they get brimmed 'as and when' they needit or is the fuel doled out per journey with stiff punishments if the fuel doesn't last as long as the management expect it to last?

 

[142094]

If TOCs plan the same as the ones I have experience of, the workings are set down and the distances are known, and the fuel levels should also be known, and the sets can be allocated (and therefore fuelled) accordingly. The other thing to consider is where the unit will be stored after its day's workings, as some stabling points may not have fuelling facilities, so again this would have to be taken into account.

 

[Lewisham2221]

Fully fuelling a unit would give the benefit of increased flexibility. A unit could have it's diagram swapped, or be diverted, without worrying (too much) about how much fuel it's carrying. The same applys to the bus and coach industry. I would imagine that the impact on performance of the weight of fuel being carried is far less substantial for the rail and bus industries than it is for the aviation industry, where I believe fuel is measured by weight rather than volume. Therefore, you aren't really achieving any savings by not fully fuelling a unit, as it will still use the same amount of fuel. Also, aeroplanes generally have the ability to refuel at every airport, on every trip.

 

[starrymarkb]

Fuel is the reason why Ultra Long Haul flights are difficult to fly profitably. Taking off with 200 tonnes of fuel, and carrying it is rather expensive ie a heavy aircraft can't climb to optimal cruise altitude and has to hang around FL300 until it has burnt enough fuel to climb higher (higher altitudes mean less fuel burnt due to air density), plus you may need to limit the payload as the fuel takes you too near Max Take Off Weight - on UK to Oz routes it's cheaper to make the stop and you can carry passengers to/from the intermediate stop (using Fifth Freedom rights) rather then just rely on end to end passengers.

Generally an airline will fuel the aircraft for the total of.

• Trip fuel -the amount needed to fly to the destination
• Alternate Fuel needed to fly to a nominated Alternative airport if unable to land at the destination - they also need enough to hold for 40 mins at cruise level at the alternate
• Reserve Fuel - the Legal minimum that must be left in the tanks in the worst case scenario of a diversion and hold
• Captain's Reserve - What the captain chooses to take in addition to the above, generally most airlines will not have a problem as long as the mick isn't taken. Ryanair insist on a max 300kgs above the calculated amount and have sent stern reminders to crew that taking more fuel then calculated without good reason is not on.

 

[Roverman]

Thanks for the answers chaps. I agree with Lewisham2221 about the flexibility of having a full tank of fuel. However with the ever rising cost of fuel I did wonder if TOC's disliked leaving units fully brimmed in Depots overnight if there was a risk of the fuel being stolen.

 

[142094]

Thanks for the answers chaps. I agree with Lewisham2221 about the flexibility of having a full tank of fuel. However with the ever rising cost of fuel I did wonder if TOC's disliked leaving units fully brimmed in Depots overnight if there was a risk of the fuel being stolen.

Depots usually have someone there 24/7, and breaking into a fuel storage area or tank will probably not go un-noticed.

TOCs will also hedge their bets and pay for fuel in bulk (same as the bus companies) to try and offset any short term price rises.