Well, the flight has been in the air for around an hour now and the two pilots and one engineer on board will be undertaking a series of tests to demonstrate how the biofuel performs in the CFM engines. The two-engined aircraft has one engine being flown on regular Jet-A1 fuel and the other engine is using the biofuel mix, which is 50% jet fuel and 50% biofuel from algae and the jatropha plant.

The pilots have climbed to a series of normal flight-level altitudes to monitor how the fuel behaves at the cold temperatures you experience thousands of feet in the air. They will then undertake a number of manoevers that would take place in a normal flight (such as accelerating and decelerating) and also some very unusual ones. For example, they will shut one of the engines down mid-air and re-start it a number of times. This was something that the Air New Zealand test flight last week also did, but they were flying a four-engine 747! These pilots will be flying on just one engine some of the time. But these aircraft are actually able to do that, if absolutely necessary.

For the flight, the aircraft has been re-certified as ‘experimental’ and the pilots on board are Continental Airline’s test crew.