Air New Zealand’s Biofuel First

On the 30th of December last year, Air New Zealand undertook the world’s first commercial aviation test flight powered by a sustainable second-generation biofuel. The airline used one of its Boeing 747-400s with one of its Rolls-Royce RB211 engines running on a blend of 50:50 jatropha-based biofuel and Jet A1. The flight, which lasted approximately two hours, took off at 11:30 a.m. (NZ time) from Auckland International Airport.

The test flight was a joint initiative between Air New Zealand, Boeing, Rolls-Royce and Honeywell’s UOP, as part of commercial aviation’s drive for more sustainable air travel for future generations (see Helen Osmaston’s article in this issue of Pacific Wings).

Air New Zealand’s Chief Executive Officer Rob Fyfe said that the flight was a milestone for the airline and commercial aviation.

“Today we stand at the earliest stages of sustainable fuel development and an important moment in aviation history. Air New Zealand is proud to be playing its role in that journey by being the first to prove the viability of a second generation biofuel such as jatropha.”

The pilot in command was Air New Zealand’s 747 fleet manager, Captain Keith Pattie. The flight, which took place predominantly over the wider Hauraki Gulf area, included a number of tests at various altitudes and under a variety of operating conditions to measure the biofuel’s performance through the engine and fuel systems.

Air New Zealand’s chief pilot, Captain David Morgan, was also aboard the aircraft. He said that the results from the flight tests will provide the airline and its partners with invaluable data in helping jatropha to become a certified aviation fuel.

Captain Morgan explained that the wide variety of tests they undertook—under normal and non-normal operating conditions—were designed to test the biofuel to its fullest extent. The tests that were conducted included:

• Takeoff: A full power takeoff, with throttles advanced as per normal operating conditions, establishing three-quarter power and then to full power.

• Climb: The aircraft climbed to 25,000 feet. At an altitude of 20,000–25,000 feet, the main fuel pump for engine one (the engine powered by the biofuel) was switched off. This tested the lubricity of the fuel, ensuring the friction of the fuel did not slow down its flow to the engine.

• Cruise: Once cruising at 35,000 feet, the auto-throttle was switched off and the crew manually set all engine controls in order that the engine pressure ratios (EPRs) and other engine performance parameters across all four engines could be checked for identical readings.

• Deceleration/acceleration: The crew controlled the fuel flow to the engine and measured the rate of change of the engine under these changing operating conditions.

• Descent: The jatropha-blend powered engine was shut down at 26,000 feet and a windmilling restart was made at 300 knots. Another engine shutdown took place at 18,000 feet, this time with a starter-assisted relight at 220 knots.

• Simulated approach and go around: When the aircraft was at 11,000 feet, the autopilot was programmed to land on a runway “located” at 8,000 feet and undertake a missed approach. This was to test the performance of the fuel under maximum thrust.

• Landing: The flight was completed with a normal landing, including the use of reverse thrust upon touchdown. The aircraft then taxied back to the hardstand, stopped all engines and restarted engine one by itself.