A passenger jet partially fuelled by fruit juice oil has taken to the skies.
The Air New Zealand Boeing 747-400 was powered by a 50-50 blend of oil from a plum-sized fruit known as jatropha and traditional jet fuel.
The two-hour flight demonstrated that greenhouse gas emissions from long-haul flights could be cut by 65 per cent by using the biofuel.
Air New Zealand's chief pilot Dave Morgan said that up to 1.5 tons of fuel could be saved in a 12-hour flight, and cut carbon dioxide emmissions by about five tons - around 60 per cent.
He called the fuel savings 'significant,' though the monetary gain will depend on the price of oil.
Andrew Herdman, director general of the Asia Pacific Airlines Association said: 'At the moment these feed stocks are still facing the challenge of reaching cost competitiveness with conventional jet fuel, particularly when the price of oil is around $60 a barrel.'
Biofuels would become competitive sooner if an emission trading system raised the price of carbon-based fuels, he added.
Air New Zealand obtained the jatropha oil for its test flight from Malawi, Mozambique, Tanzania and India. Seeds from the jatropha - a bush with round, plum-like fruit - are crushed to produce a yellowish oil that is refined and mixed with diesel.
Some environmental groups have questioned whether jatropha and other plants used as biofuels are sustainable.
They have expressed concerns about the plants' impact if more land and resources are devoted to growing them on a commercial scale.
Mr Herdman warned that while several airlines testing biofuels have shown promising results, the 'drop-ins' as the plant oils are called, still face 'another couple of years' work to demonstrate that it can be certified' as a suitable addition to jet fuel.
'It's got to perform exactly the same or better, and it's got to be a competitive price,' he said.
Mr Morgan also cautioned that 'many more steps' were needed before biofuel could become 'a commercial aviation fuel source.'
