How can a plane have too much fuel at take off ?

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TrailBlazer

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I suppose the money wasted by fuel dumps/burns is by far offset by overall fuel and capital saving in having a lighter cheaper aircraft (building structure and landing gear of the aircraft designed for limited landing weight rather than max weight) interesting compromise
Fuel dumping does not happen as often as one might think. In my almost 20 years at SAA I think I saw maybe 10 dumps. The most notable that comes to mind is on a flight from Zurich to Joburg. Just as the aircraft rotated, they lost #3 engjne... a blade broke and cleared the rest of the engine as it went through. The failure was not contained and some of the debris from #3 took out #4 as well.

Picture the situation... you've got an aircraft that weighs 369 000kg. Included in this weight would be about 160 000kg of fuel (about 200 000 litres).
You're at take-off thrust and lose two engines on the same wing. Instantly you've got asymetrical thrust...

I think the crew needed clean underwear when they got the aircraft back on the ground in Zurich. Apparently, as the first engine failed, the Flight Engineer hit the fuel dump, but even though the plane looks like a cropsprayer, it still takes time to pump 85 000 kg of fuel out.

@Airguitar will be able to confirm how long.

To build stronger airframes and landing gear to handle the max weight would incur tremendous performance penalties (higher fuel burn & less payload)
 

Tampan

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Indeed. They obviously build the air frames as strong as possible, but at the same time as light as possible. The lighter the air frame is, the more payload it can carry.
More payload = more income for the operators.

That's probably why turbine engine technology has evolved the it did. I stand to be corrected, as I'm not at all up to date on commercial aircraft, but it seems most long range airliners these days use only two engines, instead of four. Modern engines produce more and more power, while being way more fuel efficient than their older counterparts.
Modern air frames also consists of more and more composite materials.

In the end, it all boils down to better payload (paying passengers or cargo) and fuel economy.
 

The TRANSPORTER

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Fuel dumping does not happen as often as one might think. In my almost 20 years at SAA I think I saw maybe 10 dumps. The most notable that comes to mind is on a flight from Zurich to Joburg. Just as the aircraft rotated, they lost #3 engjne... a blade broke and cleared the rest of the engine as it went through. The failure was not contained and some of the debris from #3 took out #4 as well.

Picture the situation... you've got an aircraft that weighs 369 000kg. Included in this weight would be about 160 000kg of fuel (about 200 000 litres).
You're at take-off thrust and lose two engines on the same wing. Instantly you've got asymetrical thrust...

I think the crew needed clean underwear when they got the aircraft back on the ground in Zurich. Apparently, as the first engine failed, the Flight Engineer hit the fuel dump, but even though the plane looks like a cropsprayer, it still takes time to pump 85 000 kg of fuel out.

@Airguitar will be able to confirm how long.

To build stronger airframes and landing gear to handle the max weight would incur tremendous performance penalties (higher fuel burn & less payload)


Well i dont think it was just the crew needing clean underpants….

Very interesting…
 

Airguitar

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Fuel dumping does not happen as often as one might think. In my almost 20 years at SAA I think I saw maybe 10 dumps. The most notable that comes to mind is on a flight from Zurich to Joburg. Just as the aircraft rotated, they lost #3 engjne... a blade broke and cleared the rest of the engine as it went through. The failure was not contained and some of the debris from #3 took out #4 as well.

Picture the situation... you've got an aircraft that weighs 369 000kg. Included in this weight would be about 160 000kg of fuel (about 200 000 litres).
You're at take-off thrust and lose two engines on the same wing. Instantly you've got asymetrical thrust...

I think the crew needed clean underwear when they got the aircraft back on the ground in Zurich. Apparently, as the first engine failed, the Flight Engineer hit the fuel dump, but even though the plane looks like a cropsprayer, it still takes time to pump 85 000 kg of fuel out.

@Airguitar will be able to confirm how long.

To build stronger airframes and landing gear to handle the max weight would incur tremendous performance penalties (higher fuel burn & less payload)
An average 100 ton fuel jettison takes more than 50 minutes, depending on the distribution in the seven or nine fuel tanks. Different versions of 747 have different tank layouts. The latest 747-8 has a capacity of 174 tons of fuel! That said it can take even longer if the crew decides to jettison to a lower weight than Maximum Landing Weight, for safety's sake.
 
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