Today, modern airplanes use 90%+ fuel as thrust to actually move the airplane. But around 6% of fuel is used to provide secondary services like compressed air, which is the single largest secondary load on an aircraft.
More Electric Aircraft
The A380 has four variable-frequency electrical generators each delivering 150 kVA from each of its 4 engines. The APU can drive two generators. Each APU generator can supply up to 120 kVA.
That’s of total of 840 kVA of electrical capability.
On A350, each engine drives 2 main generators. Each main generator supplies a normal power of 100 kVA. The APU generator supplies a power of 150 kVA. For emergencies, the Ram Air Turbine (RAT) can provide power of 50 kVA.
That’s of total of 550 kVA of electrical capability.
The B787 aircraft, an all-electric aircraft (AEA) has 1450 kVA electric generators. Boeing has even demonstrated that the B787 can fly for more than 330 minutes on only one engine and one of the six generators and land safely.
Implementing more electrical systems & reducing the dependence on secondary pneumatic systems can bring fuel burn savings, that’s millions of gallons of jet fuel saved and tens of millions of tonnes of carbon emissions reduced every year.
Author – Arjun Singh ( Airline Captain A320/B737)